WO2024205446A1 - Detecting overheating of elements of electrical equipment - Google Patents

Abstract

The group of inventions relates to systems for detecting emergency and pre-fire situations, and more particularly to systems for automatically detecting the overheating of elements of electrical equipment and to methods for using and testing said systems. A system for automatically detecting the overheating of elements of electrical equipment includes: a gas sensor Sк intended to detect gases emitted during the heating of a monitored element, or during the heating of heat-activated gas-emitting materials on said element; a gas sensor Scp intended to determine the concentration of background gases in the air in the vicinity of the monitoring area; a controller connectable to at least two gas sensors, including at least one monitoring sensor Sк and at least one comparative sensor Scp, and capable of generating an overheating warning and/or transmitting information about overheating to another device. Also disclosed is a method for testing the system and a method for using the system to automatically detect the overheating of elements of electrical equipment. The claimed group of inventions provides for more reliable and safe operation of electrical equipment by the timely detection of faults associated with the overheating of elements thereof.

Description

DETECTING OVERHEATING OF ELECTRICAL EQUIPMENT ELEMENTS

Field of technology to which the claimed group of inventions relates

The group of inventions relates to systems for detecting emergency and pre-fire situations, namely to systems for automatically detecting overheating of electrical equipment elements, methods for their use and testing.

State of the art

According to statistics, electrical equipment malfunction is the cause of 30% of fires. Often, such fires occur due to excessive heating of conductive elements, contact connections and insulation. Timely detection of electrical equipment defects accompanied by overheating allows you to eliminate faults before fires occur and thereby reduce the number of fires and technological failures. Many methods have been developed to detect overheating of electrical equipment elements, which can be classified as direct (measuring the temperature of the controlled equipment using thermal sensors) and indirect (measuring other parameters that change due to an increase in temperature). One example of an indirect method for determining overheating is the gas analysis method, the essence of which lies in the detection by gas sensors of substances released during overheating of controlled elements due to thermal destruction or combustion.

The sensors used in the gas analytical method are semiconductor, thermocatalytic, conductometric, electrochemical or optical sensors with different operating principles, but serving the same purpose - to detect products in the gas phase that indicate the presence of overheating.

The source [RU2022250, publication date 10/30/1994] describes a device and method for informing about a pre-fire situation, based on the determination of thermal destruction products of various substances by infrared spectroscopy in three wavelength ranges, which are characterized by the absorption of hydrocarbon, chlorine-containing and oxygen-containing radicals and molecules formed as a result of thermal decomposition or ignition of electrical insulating materials. The reliability of the device is increased by subtracting signals corresponding to the permissible concentration from the simultaneously recorded values of the intensity of radiation passed through the analyzed gas-air mixture radicals, and compare this difference with the threshold value. The peculiarity of the proposed device and method is that ensuring high accuracy and efficiency of determining the concentration of hydrocarbon, chlorine-containing and oxygen-containing radicals can be achieved only in closed premises of various classes and purposes: nuclear power plants, manned deep-sea vehicles, ship premises, coal mines, compartments of space and aircraft, grain storage facilities, warehouses, etc., since when using the described invention in open spaces or in the open air, infrared sensors can also record foreign gaseous substances that absorb in the same spectral ranges to which the sensors according to the described invention are tuned. In addition, the device detects gases released when a flame occurs, i.e. an alarm is generated after a fire.

The method for detecting a pre-fire situation and preventing a fire described in the source [SU1277159A1, publication date 15.12.1986] is based on measuring the intensity of monochromatic radiation changing upon absorption at a frequency corresponding to the gaseous products of thermal destruction. When the threshold values are exceeded, a control signal is triggered to generate a fire alarm. The described method is characterized by low reliability and a high probability of false alarms. In addition, the method allows recording only actively developing thermal destruction processes close to the moment of ignition, since the control signal is generated only on the basis of the signal exceeding the threshold value without taking into account the rate of concentration increase, as well as without taking into account the background concentration of the analyzed gases in the environment.

In order to reduce the number of false alarms resulting from the detection of foreign gases by sensors, as well as to identify the facts of overheating of the controlled elements before the onset of thermal destruction, special heat-activated materials (stickers) are used, which are installed on the controlled elements. When heated above a specified threshold temperature, such stickers emit signal gases detected by the sensors. Thus, the source [JP666648, publication date 11.03.1994] discloses a device for early detection of overheating in hard-to-reach places of electrical and mechanical equipment, consisting of an odorant encapsulated in a hot-melt composition, and a sensor that detects the signal odorant. In this case, the hot-melt the composition with the odorant is placed near the controlled object. Alternative embodiments of the invention are microcapsules of a hot-melt composition filled with an odorant, as well as odorants mixed with fatty acids, such as wax. The hot-melt composition can be applied to a sheet material with an adhesive layer to obtain a heat-sensitive sticker, or mixed with an adhesive agent to obtain an odor-emitting paint. A feature of this invention is the use of hot-melt polymers that, when heated to a softening or melting temperature, can melt, flow from the controlled element or form a foam layer. Despite the fact that such systems are configured to register substances that are not contained in the air of rooms under normal operating conditions, they are nevertheless not immune to false alarms, since the sensors can detect foreign substances from the surrounding air that are close in their optical or other properties to the gases being detected.

A system for detecting local overheating of electrical equipment is also known from the prior art, which discloses the use of a microporous polymer composite material capable of releasing the contents of the pores in a mode of multiple heating and cooling cycles [RU2596953, publication date 10.09.2016]. The described system consists of a gas sensor connected to a recorder, which is connected to a signal supply system, and a polymer composite material applied to sections of an electrical circuit prone to heating and having an opening temperature in the range of 80-200 °C. Despite the fact that special marker gases are used as the contents of the pores of the polymer composite material of the device according to this document, the sensor of the device can nevertheless respond to the presence in the environment of foreign gases that are close in spectral properties to the low-boiling substances used. In addition, systems based on the use of heat-sensitive gas-emitting stickers are capable of monitoring the overheating of only that section of electrical equipment on which the stickers are installed.

It should be noted that the systems described above, based both on the use of gas-emitting stickers and the detection of gases released during the thermolysis of insulating materials, include single sensors, which are insufficient for monitoring the condition of large-sized equipment, objects consisting of several sections isolated from each other, large-sized equipment, etc. Systems are known from the state of the art that determine overheating using a gas analysis method, which include several sensors installed in different parts of the controlled objects, or configured to take air samples from various sections isolated from each other, with subsequent measurement of the concentration of certain signal gases. Such a scheme allows not only to promptly detect the fact of the occurrence of dangerous heating, but also to determine with high accuracy the location of an accident or fire and promptly take measures to minimize the consequences.

For example, the source [US2021/0299498A1, publication date 20.01.2021] describes a system for extinguishing a fire in a room, in which several stationary fire extinguishing devices are responsible for suppressing a fire in a separate area of the room, and the exact zone in which the fire occurred is determined using a matrix sensor with many pixels sensitive to electromagnetic radiation, with each pixel covering a certain area of the monitored room. When the fire zone is determined by the number of pixels that have registered an electromagnetic disturbance, the fire extinguishing devices corresponding to this zone are triggered. The described system can be easily scaled to protect large rooms or rooms with complex geometry. In addition, it is easy to program and quick to install and operate. Each pixel can be individually adjusted to the threshold of electromagnetic radiation emitted by stationary heat sources, which prevents false alarms of the system. However, each time these stationary sources are moved, dismantled or installed, it is necessary to reprogram the matrix sensor. In addition, such a system does not have high reliability, since only one pixel is responsible for a certain area of the controlled volume, and if it fails or does not work for some reason, the fire may not be detected or recorded at a late stage. Also, the described system cannot be used at industrial facilities and equipment operating at high operating temperatures, the value of which is close to the threshold.

A method and device for detecting a fire in one or more controlled zones using a system of suction pipelines connecting a plurality of controlled zones using air intakes holes, are described in the source [EP2004/009450, publication date 24.04.2004] and allow to determine with high accuracy the location of the fire by connecting multiple suction pipelines monitoring certain zones to one sensor. A similar operating principle is also disclosed in the source [US11189143, publication date 30.11.2021], which discloses an aspiration smoke detection system for detecting a fire and the location of its origin, including a unit for detecting airborne smoke particles, as well as one or more local sensors located remotely from the smoke detection unit, for measuring the properties of air from the area of interest, which is drawn into the smoke detection system during aspiration. To more accurately determine the location of a fire and reduce the number of false alarms, an aspiration detector system was developed [EP2881922, date of publication 10.06.2015], containing a dual network for supplying analyzed air, one of which operates and detects the state of the environment continuously, and the other is launched only if the first system detects signs of a fire. In this case, the second system is activated only in those zones in which the first system has detected deviations from normal indicators, with some delay, taking into account the speed of passage of the sucked air to the detector. An alarm signal is generated only if the detector of the second system confirms the data received from the first system.

Despite the fact that such systems allow not only to determine the fact of occurrence of a pre-fire situation, but also to identify its exact location with high accuracy and reliability even in large areas, as well as several unconnected rooms, their peculiarity is the delay between the moment of air suction and its analysis by the detector, caused by the distance of the detector from the air intake openings. In addition, such systems are also prone to detecting foreign gases that have arisen in the air of the monitored rooms not as a result of a fire hazardous situation, but due to other reasons, which can lead to false alarms even in the presence of a parallel confirming aspiration system described in the source [EP2881922]. Another peculiarity of such systems is the complexity of their installation and the impossibility of using them to monitor defects related to overheating of individual elements of small electrical equipment, as well as the low sensitivity of the detectors. A device for detecting fire in electrical products is known, which includes a system of suction pipes that communicates with the product being monitored through at least one suction opening and through which a representative air sample is taken; an early fire detection module having one or more sensors for detecting at least one substance in the sampled air indicating ignition; a controller for issuing an early fire detection signal in response to a result detected by at least one detection unit [US7796047, publication date 10.05.2007]. In this case, the early fire detection module is made in the form of a rack for installation in the product being monitored, and the system of suction pipes communicates with individual racks of electrical equipment subject to monitoring, using at least one corresponding suction opening, through which representative air samples are taken, analyzed in the early fire detection system. The distinctive features of the invention are its large dimensions, complexity of installation, impossibility of its use for electrical installations of non-standard shapes and sizes, as well as low sensitivity of the method and high probability of false alarms.

A method and device for detecting and determining the location of ignition in one or more controlled zones are described in the source [RU2342709C2, publication date 10.11.2007]. A system of suction pipelines, using an air intake device, supplies air samples from each individual controlled zone to a sensor for detecting at least one combustion product in the selected air samples. In this case, after receiving a positive result from at least one air sample, the air intake device analyzes a repeat sample taken from the same zone. Based on the analysis of concentrations in two consecutive air samples obtained from one zone, a conclusion is made about the location of ignition, as well as the degree of its development.

The difference in readings obtained sequentially from one sensor provides the ability to predict the development of a fire hazard situation and trigger the appropriate fire protection mechanisms when using the utility model [RU84717U1, date of publication 20.07.2009]. A similar purpose is served by the invention [RU2596063C1, date of publication 27.08.2016], which describes a method for pre-emergency, emergency and post-emergency monitoring of hazard sources in hermetically sealed manned objects, in particular submarines, based on dividing the controlled object into signal zones, each of which is controlled by a set of sensors, including those monitoring the release of highly dispersed aerosols formed as a result of overheating of various polymeric materials, electrical units and elements, determining the parameters of signal zones in various operating modes, as well as recording the excess of established values in the event of an emergency. In this case, the control system receiving signals from the sensors compares the readings obtained from neighboring sensors to conduct physical and mathematical modeling of accident development processes and prompt decision-making to eliminate the emergency situation and its consequences.

However, the above systems cannot be used to monitor the state of open objects or large areas, since they are designed to ensure explosion and fire safety of closed volumes. When using such devices and systems at large industrial enterprises or large-sized installations, especially those located outdoors, the risk of false alarms increases due to the detection of gases and aerosols that have a different source of origin and have entered the control zone of the sensors of the described systems as a result of diffusion.

Devices for measuring the composition of a gas environment are known [RU111675U1, publication date 20.12.2011; RU159702U1, publication date 20.02.2016], containing gas sensors, an analog measuring part, a transceiver, a microprocessor module, a power supply circuit for the sensor device and the device as a whole, which can be used, for example, as autonomous wireless fire alarms or toxic gas sensors. In particular, the sensors are configured to detect the concentration of methane or carbon monoxide in the air. The proposed devices solve the problem of complete energy independence from the mains supply and increase in the autonomous operation time.

The document [RU2175779, date of publication 10.11.2001] describes a method for diagnosing a pre-fire situation and preventing a fire by monitoring the values of informative parameters characterizing the state of the air at the protected facility. The technical result is to simplify the method and ensure early detection of a fire by measuring the concentration of gaseous products of thermal destruction as informative parameters: CO, CO ₂ , NOx HC1, H ₂ , CH ₄ , NH ₃ , O ₂ , Ch, H ₂ S, SO ₂ , HCOH, C ₆ H ₅ OH - and other reducing and oxidizing gases, as well as the concentration of suspended particles in the air and its temperature. In this case, for each dependence of informative parameters on time, at least one derivative value is determined in the time interval of 0.1-60 s. Based on the result of processing these parameters, a pre-fire situation is judged.

A similar mechanism of action is the basis of the device described in the source [RU95849, publication date 10.07.2010] and selected as a prototype, which determines the parameters of the gas environment, including the content of CO and H2, which allows using this device as a fire alarm. The invention consists of gas sensors, the operating modes of which are controlled by a microprocessor module, an analog measuring part, a module for processing and storing measurements, as well as power supplies for the device. The software and hardware interface is integrated into the electronic circuit of the device for transmitting data and commands over wireless networks, and during the intercalibration interval the device can operate autonomously and smoothly without replacing the power supplies, due to the optimization of the algorithm for conducting measurements and transmitting data.

To increase the reliability of operation, the devices described above may contain several identical sensors or sensors of different types designed to confirm an alarm signal received from one of the sensors. Also, the devices described are characterized by high sensitivity to the detected gases and high reliability, since the fire hazard is assessed by the concentrations of several monitored gas components. However, a common feature of these devices is the detection of the first signs of combustion, and not excessive heating. The reason for this is the high threshold concentrations of thermolysis products, corresponding to the intensive development of the defect (combustion). A decrease in threshold concentrations leads to multiple false alarms due to the presence of gases in the surrounding air that are similar in their parameters to thermal destruction products. In other words, the sensors of the devices described are highly likely to detect foreign gases from the environment, whose spectral or other properties are close to the marker substances used. False alarms of such systems are typical when used in chemical industries, where emissions may occur various chemicals, as well as near industrial plants and production and transport infrastructure.

Timely and accurate detection of emergency defects accompanied by excessive heating up to the onset of combustion or smoldering is an important task for ensuring the safe operation of various equipment, including electrical equipment. Despite the existing variety of systems and methods for detecting pre-fire and emergency situations, their common drawback, which limits their widespread use, is the high probability of false alarms when foreign gases similar in structure to thermal destruction products enter the controlled objects. Existing gas analysis systems do not allow detecting defects at an early stage of their development due to the fact that at a low concentration of thermal destruction products they cannot be reliably recorded against the background of high concentrations of other gases. Existing gas analysis systems capable of numerically determining the absolute concentration of a given gas in the air with high accuracy are used only in narrowly focused areas due to the complexity of their maintenance, large dimensions and high cost and cannot be used in standard electrical installations.

Thus, there is a need to develop a highly sensitive and reliable gas analysis system for the automatic detection of overheating of electrical equipment elements that occurs long before the moment of ignition, and taking into account the content of background gases in the air near the controlled area.

The group of inventions is aimed at increasing the reliability of identifying pre-fire situations that occur as a result of overheating of electrical equipment elements using a gas analysis method.

Terms and definitions used in this group of inventions

The terms presented below are of an explanatory nature and do not limit the scope of legal protection of the claimed invention to only the stated formulations.

“Running average value” is a function whose value at each point of definition is equal to the average value of the original function for the previous period. In relation to the present group of inventions, the running average value The gas concentration is the average value of the concentrations recorded by the sensor over a specified period up to the present moment.

"External zone" is an area of the electrical installation separated from the controlled area by walls or other partitions and communicating with the environment. In the context of the present invention, the external zone is an area of the electrical installation adjacent to the controlled area, separated from it by a wall or partition, in which the comparison sensor is installed in such a way that the effect of the signal gas on it is minimal.

The term “ignition” means the process of the beginning of combustion of a material. In relation to the claimed group of inventions, ignition includes the beginning of smoldering or burning of cables, contact connections, insulating materials or other elements of electrical equipment as a result of heating by electric current or an arc.

"Gas analysis system" - a set of products and devices that allow detecting the fact of overheating of controlled elements using the gas analysis method. The gas analysis system may include various gas sensors connected to each other by a controller, products or coatings that include thermally activated gas-emitting materials, control and receiving devices that process notifications received from the controller, an alarm system and other elements that provide visualization of the system's operation, transmission of information or control notifications.

The term “gas analytical method for determining overheating of electrical equipment elements” means a method for determining overheating of electrical equipment elements that consists of recording in the gas phase one or more substances that indicate heating of the controlled element above a certain temperature.

“Gas sensor” is a device designed to determine the content of one or more substances in a gas mixture, generating an electrical signal associated with the concentration of controlled substances in the gas phase and transmitting it to the controller. The following types of gas sensors are distinguished: semiconductor, thermocatalytic, conductometric, electrochemical, optical and other sensors. In the present invention, two types of sensors are distinguished. “Control gas sensor” ( _SK ) is designed to detect a signal gas, i.e. a gas released when the controlled element or installed on it thermally activated gas-emitting materials. "Comparison gas sensor" (S _cp ) is designed to determine the concentration of background gases in the air near the controlled area, i.e. gases not associated with overheating of the controlled element.

“Defect” is a non-compliance of an object with the requirements established by the documentation, at least for one indicator.

"Overheating Notification" is a set of commands, messages and alerts generated by the controller, intended to inform personnel or adjacent systems about the occurrence of overheating. The notification may include light, graphic, sound, electronic or other types of personnel alerts, a data packet transmitted to an adjacent system, a change in the position of a dry contact relay and other actions.

The term "controller" according to the present invention means any logical devices to which at least two gas sensors can be connected via wired or wireless communication, one of which is a monitoring sensor and the other is a comparison sensor, in particular cases the controller can be connected to one of the sensors by combining with it. The controller analyzes signals from the gas sensors using a set of logical operations and generates a notification informing about the occurrence of overheating. Depending on the user characteristics, the notification can be generated in light, sound, graphic or other form, and also represent a data packet for transmission to adjacent systems or a change in the position of a dry contact relay. The notification can be transmitted by the controller to another device, in particular, an external receiving device or a higher-level system. In this case, the notification can additionally include a control command, for example, to break the electrical network, start the fire extinguishing system, etc.

The “controlled zone” is understood to be an area of the electrical installation, fully or partially limited by walls or other partitions, inside which there are elements of electrical equipment controlled by one of the sensors of the system. In a particular case, the controlled zone may be the internal volume of an electrical panel, a section of distribution devices, a switch compartment, a box of the winding distribution block, etc., inside which there are elements subject to control. The controlled zone may be hermetically or non-hermetically separated from the external zone and other controlled zones. The degree of leakage of the controlled zone of electrical equipment can be determined by the IP class parameter.

The term “controlled element” describes an element of electrical equipment, the overheating of which is determined using a gas analysis system according to the claimed group of inventions.

“Part per million” or “ppm” is a unit of measurement of any relative values equal to T10~ ⁶ of the base indicator. With regard to the claimed group of inventions, the value ppm means the content of the measured gases in the controlled area at a given time and determines the absolute concentration of these gases. The concentration of gases expressed in parts per million can be converted to a percentage concentration as follows: 1% = 10,000 ppm.

The concept of “multiple system activations” characterizes the ability of a gas analytical system to register the fact of overheating in repeated “heating-cooling” cycles more than once without replacing system components.

The term “model gas” means a substance or group of substances that are used in testing the system and include compounds that are similar in certain characteristics to signal, background gases or substances released during overheating of a thermally activated gas-emitting material.

The term “overheating (heating, heating) of electrical equipment elements” means that electrical equipment elements reach a temperature exceeding the normal operating temperature due to the occurrence of a defect, arc discharges, and other reasons.

The concept of “threshold concentration of signal gas” or “threshold of gas analysis system” is the minimum concentration of signal gas or the minimum value of the signal of the gas sensor of the gas analysis system at which an alarm notification is generated.

The term “self-diagnostics” describes a set of processes performed automatically, aimed at determining the operability of the system.

“Gas sensor signal” and “gas sensor signal value” are an electrical signal generated by a gas sensor, one of the parameters of which depends on the concentration of specified substances (e.g., signal or background gases) in a gas mixture. In accordance with the present invention, the signal transmitted from the gas sensor to the controller via wired or wireless communication. The gas sensor may additionally include logic modules that convert or modulate the signal, various filters, signal amplifiers, and other components.

The term “signal gas” means a substance or group of substances that are released into the gas phase when the controlled elements or thermally activated gas-emitting materials installed on them overheat and which the gas sensor is configured to detect.

The “degree of leakage” of a closed volume characterizes the ratio of the total area of permanently open sections of a given volume to the area of enclosing structures, expressed as a percentage. The IP protection class parameter can also be used as a quantitative assessment of the degree of leakage of electrical cabinets and distribution boards.

The IP code (according to GOST 14254-2015) is a codification system used to indicate the degrees of protection provided by enclosing structures from access to hazardous parts, ingress of external solid objects, water, and to provide additional information related to such protection.

The term "thermally activated gas-emitting material (TGM)" refers to a material capable of releasing gas when heated above a specified threshold temperature, primarily in the range of 60-150°C. In particular, such material may be part of thermally activated gas-emitting stickers, clips, cambrics, other products, as well as special coatings (varnishes, paints, etc.). The thermally activated gas-emitting material may include microcapsules or microporous components containing signal gases, the detection of which is configured by the gas sensor. The mass fraction of substances that pass into the gas phase when the thermally activated gas-emitting material is heated to the threshold temperature must be at least 30%. The temperature at which the thermally activated gas-emitting material begins to emit gas is called the threshold gas emission temperature or simply the threshold temperature. Depending on the structure of the thermally activated gas-emitting material, when heated to the threshold temperature, the gas contained therein may be completely or partially released. In the latter case, when reheated above the threshold temperature, the material will again release some of the contained gas. This property of TGM provides the possibility of multiple operation of the gas analytical system.

The term “background gas” describes a substance or group of substances that may be present in the air of the operating zone of an electrical installation, can be detected by a gas sensor, and the occurrence of which is not associated with overheating of the controlled elements or thermally activated gas-emitting materials installed on them.

The term “electrical equipment” refers to a set of devices designed for the production, distribution, transmission and consumption of electrical energy, the operation of which is based on the principles of electrical engineering.

“Electrical cabinet” or “distribution board” is a frame in which various electrical equipment is installed, including that intended for receiving and distributing energy. “Closed electrical cabinet” is a body, usually made of metal or plastic, completely or partially closed on all sides. The shield differs from the cabinet in that the equipment is mounted in a special niche in the wall and is closed only on the front side.

The essence of the group of inventions

The claimed group of inventions is aimed at increasing the reliability and accuracy of identifying the initial stages of defects in electrical equipment elements using a gas analysis method that takes into account the current concentration of background gases determined using a comparison sensor.

The problem that the claimed group of inventions is aimed at solving is the creation of a system, a method for testing it, and a method for automatically detecting overheating of electrical equipment elements that are highly reliable and sensitive.

The technical result of the claimed group of inventions is to increase the reliability and safety of operation of electrical equipment due to the timely detection of defects accompanied by overheating of electrical equipment elements. To achieve the specified technical result, the group of inventions uses the determination of overheating by a gas analysis method using a comparison sensor. The comparison sensor allows taking into account the concentration of background gases in the air near the controlled area, which allows reduce the threshold concentration of signal gas when generating an overheating notification, and also reduce the number of false alarms.

In the first variant, the specified technical result is achieved through the use of a system for automatic detection of overheating of electrical equipment elements, including:

- gas sensor S _K , designed to detect gases released during heating of the controlled element or thermally activated gas-emitting materials installed on it,

- gas sensor S _cp , designed to determine the concentration of background gases in the air near the controlled area;

- a controller configured to be connected to at least two gas sensors, including at least one monitoring sensor S _K and at least one comparison sensor S _cp , and to generate a notification of overheating and/or transmit information about such overheating to another device.

An additional group of inventions may include the use of thermally activated gas-emitting materials, primarily of multiple action (TGM) and special signal processing algorithms that allow recording a defect before the onset of irreversible changes in the structure of materials of the controlled elements, for example, thermal destruction of insulation. TGM used to detect overheating of electrical equipment elements have a fixed threshold gas emission temperature, which is usually lower than the temperature of the onset of irreversible destruction of electrical equipment elements. Thus, the use of TGM allows recording overheating at a stage that allows maintaining the operability of electrical installation elements. In addition, the ability of some TGM to emit signal gas in repeated heating/cooling cycles provides the ability to repeatedly detect overheating of electrical equipment elements without replacing the system or its individual parts and to clarify the remaining service life of the equipment.

The control object according to the present invention is selected as elements of electrical equipment. This is due to several reasons. Firstly, the reliability and trouble-free operation of electrical installations is an important and integral factor in ensuring the safety and reliability of the operation of almost all types of production, social facilities, transport, urban infrastructure, etc. Secondly, electrical installations are a source increased fire hazard. As already noted at the beginning of the application, fires due to violations of the rules for the operation of electrical equipment rank first after careless handling of fire. Thirdly, in most cases, high-voltage electrical installations do not allow for their visual inspection under load, which does not allow for timely detection of defects using thermal imaging inspection or other visual inspection methods. It should be noted separately that the materials from which electrical equipment is made: wires, cables, insulators or electrical equipment housings - in most cases are non-flammable. It is not possible to detect their overheating with standard fire (smoke, heat, infrared and other) sensors.

The need to use a comparison gas sensor that determines the concentration of background gases in the air near the controlled area is associated with the need to generate an alarm about overheating when the monitoring sensor detects signal gas in the lowest gas concentrations. The task of the comparison sensor is to eliminate false alarms caused by constant changes in the concentration of background gases in the ambient air, and, as a result, the possibility of reducing the response threshold of the gas analysis system and implementing an adaptive threshold. The expediency of monitoring signal gas in minimum concentrations is associated with the following circumstance. As a rule, the rate of development of defects associated with overheating of electrical equipment exponentially depends on the temperature. In other words, the lower the temperature, the slower the defect develops, and the greater the time reserve for repairs or preparation for shutdown. From a technical point of view, it is most expedient to detect defects at the earliest stages of their development. However, with minor overheating, the concentration of emitted gases is very small. This is due not only to the low rate of depolymerization reaction, but also to the weathering of the released gases from the electrical installation over time. Currently, a large number of sensors are known that allow recording products released during insulation decomposition, or special signal gases in extremely low concentrations equal to units or tens of ppm. However, such sensors work well only in an ideal environment, i.e. at constant temperature, humidity, CO2, oxygen and other atmospheric gases. It is impossible to ensure such “ideal” conditions in electrical installations. Changes in the impact of the above factors during operation lead to either the need to significantly roughen the system and raise the response threshold of the gas analysis system, or to put up with a large number of false alarms. The above circumstance is one of the significant factors limiting the scope of application of the gas analysis system. An equally significant factor is the change in sensor sensitivity over time, as well as the dependence of the sensor signal on temperature, magnetic fields and other factors.

The gas analysis system must have the necessary versatility, and also operate effectively and reliably regardless of external conditions and the type of insulation materials used. As a rule, it is impossible to predict the environmental conditions under which the system will be operated, as well as the composition and amount of background gases to which the system will be exposed during operation.

Signal gases, for the detection of which gas sensors used in a gas analysis system are configured, are not an individual substance, but a set of substances whose qualitative and quantitative composition may vary significantly. For this reason, sensors used in a gas analysis method are usually configured not for an individual substance, but for a group of substances united by the presence of one or another structural fragment.

Taking into account that any parameter measured by such sensors directly characterizes the concentration (content) of a gas or group of gases in the gas-air environment, in this application the term "concentration" will be used when referring to the content of signal or background gases. In this case, the sensor generates a signal, the value of which is determined by the measured parameter of the gas mixture, therefore it can be said that the value of the signal received from the sensor by the controller also characterizes the content of a certain set of substances in the controlled area and is somehow related to their concentration.

The main difficulty in increasing the sensitivity of gas sensors when detecting signal gases is that when the sensor is configured to determine the maximum value of the parameter X - 1 _Ш ах(Х), which characterizes the signal gas to the greatest extent (Fig. 7a, solid lines b), it can nevertheless respond to the presence of other background substances, the maximum value of the parameter X for which is close to the determined value. This is due to the fact that, as a rule, the graphs of the dependence of the value of the parameters 1(Х) on the concentration have a shape close to the Gaussian distribution. Therefore, even if there is a mismatch maxima of the values of the parameters X, the standard deviation from 1 _max (X) of the background gases (Fig. 7a, dotted lines a) can overlap with I _max (X) of the signal gases, which, with a high content of foreign substances, can lead to the system being triggered.

The use in the system of products including thermally activated gas-emitting materials (TGM) and installed on the controlled elements, or thermally activated gas-emitting coatings applied to these elements, makes it possible to adjust the sensors to register specific signal gases that are released when the TGM is heated above the threshold temperature. Such signal gases are usually selected in such a way that the maximum value of the parameter X - Imax(X) - differs as much as possible from the maximum values of this parameter for other background gases (for example, CO2, oxygen, water and other atmospheric gases), as shown in Fig. 7a, thick line c. Nevertheless, in practice, the dependence I(X) registered by the sensor will look similar to the graph shown in Fig. 76, and since the content of background gases under certain conditions can be many times higher than the concentration of the signal gas, there is a partial overlap of the region with the maximum value of the parameter X, characteristic of signal gases released from TGM, and the occurrence of false alarms of the system.

In this regard, an important task of modern systems for detecting overheating using gas analysis methods is to combine the ability to register low levels of gases released during overheating of controlled electrical equipment elements or thermally activated gas-emitting materials installed on them, and to minimize false alarms. We have found that taking into account the current content of background gases allows for a multiple increase in the sensitivity of the system, as well as a significant reduction in the number of false alarms that occur due to the detection of foreign gases by sensors.

The essence of the present invention is that the detection of gases released during heating of controlled elements or thermally activated gas-emitting materials installed on them occurs by a control sensor taking into account the concentration of background gases determined by a comparison sensor in the air near the controlled zone. Moreover, the control sensor is installed in the same area as the controlled element (controlled zone), and the comparison sensor is near the controlled zone, but outside it, that is, in such a way in such a way that the comparison sensor is equally affected by all the same gases that affect the monitoring sensor, with the exception of gases released during overheating of the monitored elements or heat-activated gas-emitting materials installed on them. Typically, the monitoring sensor is located inside the electrical equipment next to or above the monitored element (elements), and the comparison sensor is either outside the electrical installation or in another part of the electrical installation (an adjacent compartment or cell). The comparison sensor sets a zero value (baseline), relative to which the controller analyzes the gas content in the monitored zone and makes a decision on generating an alarm; and/or makes it possible to distinguish a false alarm from a true one based on the difference in signals recorded by the comparison sensor and the monitoring sensor. This approach makes it possible to lower the threshold value of the content of monitored gases when generating an alarm and to reduce the probability of false alarms. In addition, since the comparison sensor is operated under the same conditions as the control sensor, the poisoning of the sensing element, the temperature dependence of the signal, and other parameters of the comparison sensor and the control sensor will be close. This allows for an even greater increase in the sensitivity of the method. Taking into account the exponential dependence of the defect development rate on temperature, the use of the comparison sensor allows for a significant increase in the detection of defects at early stages and a reduction in the number of false alarms.

In the simplest case, the system takes the value of signal 1 _sr , characterizing the content of background gases and generated by one or more comparison sensors, as the baseline. The controller generates an overheating notification when the value of signal 1 _k , characterizing the content of signal gases and recorded by one or more monitoring sensors, deviates from this baseline in the direction of increase in accordance with the formula: 1 _K - 1 _sr > 0. If the value of signal 1 _k does not exceed the value of signal 1 _sr or if the values of these signals are equal, i.e. when 1 _k - 1 _sr ^<= 0, the controller does not generate an overheating notification. Thus, the use of the system according to the claimed group of inventions makes it possible to recognize and filter out false alarms by comparing the values of signals recorded by the monitoring sensor with the values of signals recorded by comparison sensor, according to the simplest algorithm given above, or according to more complex algorithms disclosed in the description below.

The present invention can use various methods of comparing the values of signals registered by sensors characterizing the gas content: absolute values of signals at each moment in time, averaged values of signals for different time periods, integral or differential values of signals (in the latter case, not the relative values of the signals themselves will be taken into account, but the rate of their growth), averaged values of signals obtained from several external comparison sensors or monitoring sensors can be compared. All these approaches allow optimizing the operation of the system for a specific application task, since each type of defect has its own development features. What is common in all cases is that the signals registered by the monitoring sensor, recording the total content of background and signal gases, and the comparison sensor, recording the concentration of only background gases, are analyzed.

Accounting for the current content of background gases by determining their concentration in the air near the controlled area allows for a reduction in the threshold concentration of the signal gas required to generate a notification, as well as for recognizing and minimizing false alarms associated with changes in the composition of atmospheric (background) gases over time. Early detection of defects associated with overheating of electrical equipment components ensures increased reliability and safety of electrical equipment operation.

The claimed system may contain more than one S _cp , and/or more than one S _K . If the system contains more than one S _cp , the generation of a notification about overheating of electrical equipment elements and/or the transmission of information about such overheating to another device may occur by comparing pre-averaged values of signals characterizing the content of background gases detected by all or some S _cp with the same or different contribution of each individual sensor. Similarly, when using several monitoring sensors, different algorithms for calculating the value of the signal gas may be used: by the average concentration or by the smaller recorded value of the signal.

In some cases, the system can implement adaptive logic of operation. In this case, the set threshold concentration value changes during operation based on the maximum change (oscillation amplitude) of the signals the monitoring sensor or the comparison sensor over a long period. This approach is preferable, since, depending on the external conditions and the characteristics of the electrical equipment being monitored, it is not always possible to reliably determine the threshold values of the signal gas, and the use of a single fixed (universal) threshold value for all types of electrical installations can lead either to false alarms or, on the contrary, to a decrease in the sensitivity of the system. In the case of adaptive logic, the controller generates an overheating notification when the signal of the monitoring sensor exceeds the signal of the comparison sensor not by a fixed threshold value, but by a constantly changing threshold value. In the simplest case, the adaptive threshold value can be equal to the maximum difference in values between the monitoring sensor and the comparison sensor, multiplied by a constant (the value of which is mainly in the range from 2 to 5). In another calculation option, an array of signal values obtained from all comparison sensors forms a variance (i.e. a measure of the spread) of the background gas signal values relative to the average value of these signals. Based on these data, the controller can also calculate the standard deviation, which is usually the square root of the dispersion, or calculated using other calculation methods. The overheating notification is generated only if the signal registered by one of the S _K is out of the set formed by the dispersion or standard deviation from the average value of the signals S _cp . If the S _K values are within the specified set, the overheating notification is not generated. In this case, the entire set of calculated values is formed depending on the data received from all S _K and Sep at each moment in time.

The adaptive threshold value and the use of the above-described principle of operation of the system in the case of the presence of several S _cp and/or S _K additionally increases the reliability of detecting overheating of electrical equipment, since it allows to reduce the absolute value of the threshold concentration, upon detection of which the S _K sensor triggers the system, and makes the system independent of the established threshold values.

If the system contains more than one S _K , the generation of a notification about overheating of electrical equipment elements and/or the transmission of information about such overheating to another device may occur when the average value is exceeded. values of signals characterizing the gas content registered by all or some S _K , with the same or different contribution of the exceeded signal values registered by each individual S _K . An increase in the number of monitoring sensors additionally contributes to an increase in the reliability of detecting overheating of electrical equipment elements, especially in large-sized electrical equipment, such as, for example, large-volume distribution cabinets, since each S _K will analyze a certain volume of air surrounding it. Gases released during overheating of equipment elements or thermally activated gas-emitting materials installed on them are initially localized in the immediate vicinity of the overheating point and spread throughout the volume of electrical equipment over time due to diffusion processes, the rate of which depends on many factors, for example, forced ventilation. In this case, it is important that S _K is located as close as possible to the overheating point in order to reduce the delay in the formation of a local overheating notification by the system. Therefore, placing several S _K in different places of the monitored zones will allow timely detection of pre-fire situations associated with the release of polymer insulation products and other materials.

In another embodiment, the system can use a combination of a fixed threshold value and adaptive logic and be based on the calculation and comparison of running average parameters recorded by the sensor. The controller, receiving data from the monitoring sensor, calculates two indicators: a long-term running average calculated as the average value of the recorded parameters over a long period of time, characterizing the rate of change of the air mixture parameters not associated with overheating of the controlled element (usually more than 5 minutes) and a short-term running average calculated for a time period equal to the time of active growth of the concentration of signal gases, when the controlled element reaches the threshold temperature (preferably less than one minute). The long-term running average actually characterizes the presence of background gases, the concentration of which usually changes slowly over time, and sets the baseline relative to which the short-term running average is compared, characterizing the average concentration of signal gases. The threshold value of the difference between the short and long running averages (calculated as the difference between these parameters or by more complex algorithms) can either be set during manufacturing, design, commissioning of equipment, start-up and adjustment works, or be adjusted in automatic mode taking into account fluctuations in the concentration of background gases during operation, recorded, among other things, by the comparison sensor. The accuracy and sensitivity of the system can be adjusted by selecting the time interval for calculating the long-term running average: the longer the period of time taken into account, the smaller the contribution to the value of the short-term running average will be made by background gases. Such adjustment can also be carried out automatically depending on the data received from the comparison sensor. The presence of S _cp is necessary not only for adjusting the adaptive threshold and the time period for determining the long-term running average, but also for confirming that the threshold value has been exceeded by the monitoring sensor, in the event of a sharp increase in the concentration of signal gases in the ambient air for reasons not related to overheating of the monitored elements.

As a rule, the average volume of one cell of electrical equipment (e.g., electrical panels, complete switchgear units, low-voltage complete devices, winding starter distribution block boxes, etc.) is from 100 l to 1000 l (1 m ³ ). It was experimentally established that the mass of products released from insulating materials during overheating of electrical equipment elements or thermally activated gas-emitting materials installed on them, for the determination of the content of which gas sensors are configured, does not exceed 1 g. Under normal conditions, the molar volume of any gas is taken as 22.4 l/mol, the molar mass of air is 29 g/mol, and the average molar mass of signal gases is 200 g/mol. Then the concentration of measured products in the controlled area will be on average 30-300 ppm. Therefore, for reliable and reliable operation, the system must record an excess of signal gases in the range of 30-300 ppm. At the same time, the concentration of other gases that can also be detected by sensors is significantly higher, for example, the concentration of CO2 in the atmosphere in some cases can reach 1000 ppm and higher. This fact additionally indicates the need to use a comparison sensor.

As noted above, in order to continuously monitor the emission of gases formed during overheating of electrical equipment elements or thermally activated gas-emitting materials installed on them, it is not advisable to quantitatively determine only one specific substance, but it is necessary to record a group of substances similar in structure. For this purpose, it is necessary to select a sensor that changes some parameter during adsorption or reaction with a certain class of substances. For example, a sensor can measure the conductivity of the medium between two sensitive elements, depending on the composition of this medium, and generate a signal, the value of which will be the higher, the greater the content of gases that caused this change. In this case, the absolute concentration of signal gases will be unknown, but its change will lead to a change in one of the sensor parameters, which will lead to the formation of a signal by the gas sensor and will indicate a change in the composition of the air environment. Sensors that detect a change in the composition of the gas-air environment by an indirect change in their parameters and generate a signal proportional to this change are widely used in various gas analytical systems due to their convenience, reliability, ease of use, compactness and low cost, and therefore their use is preferable within the framework of the claimed group of inventions.

In the claimed group of inventions, semiconductor, thermocatalytic, conductometric, electrochemical, optical and other types of sensors can be used as gas sensors, each of which has a number of features.

Thermocatalytic sensors monitor heat generation resulting from oxidation of the analyzed gas on the surface of a thermocatalytic element, which is a platinum thread heated to a high temperature and covered with a catalyst layer, and the heat generation value directly depends on the molar concentration of this gas. Their advantages include high speed and the presence of an explosion-proof shell, however, the thermocatalytic element quickly degrades, and the sensor itself has high energy consumption and requires constant connection to the electrical network, which limits the scope of their use.

The principle of operation of electrochemical sensors is based on the interaction of the analyzed gas with a sensitive layer located directly on the working electrode or in a layer of electrolyte solution near it. Such sensors provide high selectivity and measurement accuracy, but the presence of liquid electrolyte reduces their service life and makes them less preferable for use in electrical installations. Optical gas sensors are based on the absorption of gases of certain wavelengths, usually in the infrared range. The absorption coefficient is directly proportional to the concentration of gases. The advantage of optical sensors is a long service life and the absence of the aging effect, since the sensitive element of the sensor is protected from the effects of the analyzed gases. Sensors of this type can also operate in a wide range of concentrations. However, despite the fact that optical sensors can be adjusted to absorb certain wavelengths, such sensors are highly sensitive to the concentration of water, carbon dioxide and other compounds that may be contained in the atmosphere (e.g., flammable liquid vapors). This leads to significant fluctuations in the measured parameters of both the control sensor and the comparison sensor over time. The latter circumstance prevents a decrease in the sensitivity threshold of this type of sensors. Adjusting optical sensors to determine the absorption of wavelengths allows increasing selectivity and sensitivity, but significantly complicates the system.

Semiconductor sensors are one of the main types of sensors used in gas analysis systems. Their operating principle is based on the change in the resistance of the sensitive layer when exposed to the measured gas. Wide-bandgap semiconductors (oxides and chalcogenides of metals: SnO ₂ , ZnO, TiO ₂ , WO3, SnO ₂ etc.) are usually used as such a sensitive layer, reversible chemisorption of the measured gases on which leads to reversible changes in conductivity. Their advantage is not only high sensitivity, a wide dynamic range of measured concentrations, but also low energy consumption.

The preference for using sensors of this type for the declared system of automatic detection of overheating of electrical equipment elements is due to the fact that when the insulating materials of the controlled electrical equipment elements overheat, as a rule, including cross-linked polyethylene (PE), polyvinyl chloride (PVC), rubber, silicone, epoxy resin, etc., are released reducing gases (for example, ethylene, vinyl chloride, isoprene, butylene, НС1, _Н2 , СО, etc.), which can be determined by oxidizing semiconductor materials in low concentrations. At the same time, semiconductor sensors react weakly to the products of complete oxidation of organic substances, for example, _СО2 , oxygen, and other substances with low reactivity that are present in the air. in relatively high concentrations. This allows for an additional increase in the sensitivity of the system and ensures its reliable operation at low concentrations of substances formed as a result of overheating of electrical equipment elements (for example, the occurrence of partial arc discharges), indicating the initial stage of defect development.

It should be noted that the claimed group of inventions is not limited to the use of a gas sensor of a certain type. For reliable and accurate operation of the claimed group of inventions, an important criterion when choosing the type of sensors used is the selective registration of products released during overheating of insulating materials of electrical equipment elements or thermally activated gas-emitting materials installed on them, relative to gases that may be present in the atmosphere during normal system operation. Such gases include: flammable liquids used in servicing electrical installations, as well as during repair and painting work; flue gases released during operation of internal combustion engines, boiler houses, gas turbines, etc.; methane, gasoline or diesel fuel vapors, emissions from chemical plants; odorants; detergents and disinfectants, etc.

All the sensors described above, which can be used in the claimed group of inventions, provide continuous and repeated recording of products released during overheating of the controlled elements of electrical equipment or thermally activated gas-emitting materials installed on them, as well as background gases both in the controlled zone and outside it throughout the entire service life, which also ensures the reliability of detecting overheating of elements of electrical equipment.

In a preferred embodiment, the sensors used in the claimed system are semiconductor type sensors, the sensitive element of which is designed with the possibility of continuous or repeated detection of gases released during heating of insulating materials, including, in particular, cross-linked polyethylene (PE), polyvinyl chloride (PVC), rubber, silicone, epoxy resin. In particular, the sensors are designed with the possibility of recording the said gases in concentrations from 30-100 ppm.

To increase the sensitivity of the system and detect defects with a heating temperature below the thermal destruction temperature of insulating materials In addition to the comparison sensor, it is preferable to use thermally activated gas-emitting materials (TGM). In special cases, the sensitive element of the sensors is designed with the ability to register products released during heating of thermally activated materials, preferably multiple action, included in the composition of products or coatings installed or applied to the controlled elements of electrical equipment.

TGMs contain a signal gas encapsulated or otherwise hermetically sealed from the environment, the release of which occurs at a relatively low temperature. Encapsulated materials available on the market have a high content of signal gases (more than 30%) and an initial temperature of gas release specified with sufficient accuracy. TGMs are usually used in the composition of special stickers, clips, varnishes or coatings.

Thermally activated gas-emitting materials are suitable for use in the following cases:

- control of overheating of metal elements that are not covered with polymer materials and are not capable of releasing signal gas when overheated;

- control of other elements of the electrical installation at a temperature below the onset of decomposition (thermal destruction) of polymeric materials;

- selective control of individual elements (those on which TGMs are applied or installed);

- increasing the sensitivity of the system and reducing the number of false alarms due to the fact that the amount of signal gases released from the TGM is significantly higher than during the decomposition of polymer insulation. The signal gases contained in the TGM can be selected in such a way that the sensitivity and selectivity of the sensor with respect to these gases is maximum.

Another advantage of using thermally activated gas-emitting materials is the ability to record the overheating temperature of the controlled element by using TGM with a given threshold temperature.

Gas release from thermally activated materials when heated to a threshold temperature usually occurs abruptly, which leads to a sharp increase in the concentration of signal gases. This allows for an increase in the reliability of detecting overheating of electrical equipment components, especially in relation to the system response algorithms described in this application. In addition, as already mentioned above, the signal gases used in TGM are usually selected in such a way that their measured parameters are outside the areas overlapping with the parameters of background gases, which allows for more selective adjustment of the sensitive elements of the sensors, thereby increasing their sensitivity. High sensitivity allows for the use of products including TGM of relatively small sizes, for example, stickers 1-20 cm long and 0.5-5 mm thick, or coatings including TGM. On the one hand, the content of signal gases in such products (coatings) is small, due to the small volume of the heat-sensitive layer. On the other hand, this amount is sufficient for reliable registration of overheating. The small size of the products containing TGM allows them to be installed on small elements of electrical installations: wires with a cross-section of 0.75 ^mm2 , terminal blocks, blocks, circuit breakers and other small equipment, the overheating control of which is impossible by other methods. Another important advantage of increasing sensitivity by the described method is the possibility of using the invention, including TGM, even in ventilated electrical installations.

Thus, the use of the system according to the present group of inventions together with the TGM allows to significantly increase sensitivity, reduce the probability of false alarms and register the achievement of overheating of local elements to specified temperatures before the development of emergency defects or fire.

In electrical equipment, as a rule, heating is associated with the load current. The dependence is quadratic and obeys the Joule-Lenz law. Since the load of electrical equipment often changes significantly during operation, after the occurrence of a defect, heating can occur cyclically. In this case, the insulation materials of the heated element will gradually, from cycle to cycle, emit a small portion of signal gas, up to the complete destruction of the material. In this case, the system according to the claimed group of inventions will generate a notification at each overheating. In the case of thermally activated gas-emitting materials, as already mentioned above, the multiple registration can be ensured by the features of the TGM structure, for example, the content of a large number of microencapsulated particles of different sizes and different opening temperatures. In the claimed group of inventions, as products including TGM, it is preferable to use heat-activated gas-emitting stickers of multiple action, made of a polymer composite material containing a continuous phase formed by a thermosetting polymer, the pores of which are filled with a sulfur-containing odorant or freon [EA201890482, publication date 06/29/2018]. Due to the special structure of the material and the use of thermosetting polymers, when a given temperature is reached, only part of the pores open with the release of the gas contained in them and the integrity of the remaining pores is maintained, which ensures multiple gas emission in repeated heating/cooling cycles. Therefore, the use of such heat-activated stickers provides the possibility of multiple detection of overheating of electrical equipment elements without replacing the system or its individual parts. In addition, in these stickers, the combination of a polymer composite material with odorants filling its pores ensures not only the integrity of the material at temperatures close to, but not reaching, the opening temperature, but also the explosive destruction of part of the pores when heated to threshold values, leading to the simultaneous release of a sufficient amount of signal gas for detection by the sensor. Thus, the use of predominantly thermally activated gas-emitting stickers described in the source [EA201890482] ensures multiple triggering of the system according to the claimed group of inventions, as well as its speed.

In a preferred embodiment, S _K and S _cp have a sensing element of the same type and are designed to register gases belonging to classes of compounds selected from the list: halocarbons, hydrogen halides, halohydrocarbons, alkenes, alkanes, mercaptans, acids or mixtures thereof, preferably gases selected from the list: carbon tetrafluoride, tetrafluoroethylene, tetrachloroethylene, trifluorochloromethane, chloroform, dichloromethane, methyl chloride, methyl bromide, trifluoromethane, ethyl chloride, vinyl chloride, hydrogen fluoride, hydrogen chloride, ethylene, propylene, butadiene, isoprene, methane, ethane, butane, hexane, methyl mercaptan, dimethyl sulfide, ethyl mercaptan, diethyl sulfide, nitric acid, nitrous acid or mixtures thereof.

As noted above, the sensors of the gas analytical system according to the claimed group of inventions generate a response (signal) not to any specific gas, but, most often, to several gases (gas mixture) to which the sensors are tuned. systems. In this case, some gases can make a greater contribution to this response, while others make a smaller contribution. Thus, the monitoring sensor should be installed in such a way as to detect to the maximum extent the products released during overheating of the monitored elements or thermally activated gas-emitting materials installed on them, and the comparison sensor, accordingly, should be installed in such a way as to detect to a minimum extent the products released during overheating of the monitored elements or thermally activated gas-emitting materials installed on them, and to the maximum extent the background gases are registered. It is preferable to install the monitoring sensor above the monitored element, and the comparison sensor - in such a way as to prevent it from getting on it.

The values of the signals characterizing the content of gases, for the detection of which the sensitive elements in the sensors S _K and S _cp are configured, are transmitted to the controller, which processes the data received from both sensors either simultaneously or with a certain time delay, determined experimentally for a specific electrical installation.

The controller according to the claimed group of inventions is designed with the ability to generate a notification about overheating after receiving and processing using a set of logical operations of data received from sensors associated with it. The controller can issue a notification about overheating of the controlled elements in the form of a sound, light, graphic or other notification, or in the form of a control command, for example, to turn off or reduce the load. The controller can also transmit the generated notification to another device, for example, to an external receiving device. The type of notification used about the occurrence of a pre-fire or emergency situation is determined based on the technical documentation of the controlled electrical equipment, as well as the ease of use of the system.

In special cases, the controller is designed with the ability to generate a notification about overheating of electrical equipment elements, and/or control them, when S _K is exposed to products released during overheating of controlled electrical equipment elements or thermally activated gas-emitting materials installed on them, in a concentration higher than a specified limit value, regardless of the current concentration of background gases determined by S _cp . This capability allows for the detection of rapidly developing defects that lead to instantaneous overheating, ignition, and excess concentration of signal gases in all controlled zones of the electrical installation. In this case, timely shutdown of the electrical installation allows preventing the development of a fire and minimizing damage to adjacent equipment.

To further ensure reliability and accuracy of detecting overheating of electrical equipment elements, the declared system can use various algorithms when generating a notification about overheating of electrical equipment elements and/or transmitting information about such overheating to another device.

The controller may use one or more of the following algorithms for processing signals received from the gas sensors: calculating the running average value from each sensor for a specified period of time; adjusting the reference (zero) value; determining the reduced running average value as the difference between two running average values received from one sensor for two different periods of time, preferably a short period of less than one minute and a long period of more than 5 minutes; comparing the reduced running average value with a threshold value and generating an overheating notification if it is exceeded; determining the average value of the signal received from different sensors by averaging the reduced running average values; comparing the difference between the reduced running average values of the signals from the comparison sensor and the monitoring sensor, including those calculated for different periods of time, with a specified threshold value; determining the growth rate of the reduced running average value and comparing it with the set threshold value; comparison of the signal received from the control sensor with the set threshold value; determination of the rate of growth of the difference between the reduced running average value of the signal of the control sensor and the comparison sensor and its comparison with the established threshold value; determination or change of threshold values based on the analysis of the values of signals received from the sensors during operation; adaptive response threshold.

The implementation of the claimed group of inventions using the specified algorithms will be described in more detail in the section “Implementation of the invention”.

In special cases, the system according to the claimed group of inventions can be additionally equipped with temperature sensors to further increase the accuracy and determine the numerical value of the temperature to which overheating occurred.

In preferred embodiments, the claimed system additionally has a self-diagnostic function informing about the need to replace the sensitive element of one or more sensors, which increases the overall safety of using both the system and the electrical equipment as a whole. Sensor diagnostics, as a rule, consists of regularly automatically measuring the resistance of the sensitive element and/or heater or other sensor parameters and generating a corresponding notification when the resistance value goes beyond the established limits.

In a particular case, the controller can generate a notification about overheating of the controlled element and/or transmit information about such overheating to another device when one or more S _cp are exposed to products released during overheating of the controlled elements or thermally activated gas-emitting materials installed on them, and also taking into account the concentration of background or signal gases that have affected the sensors during the previous period of time.

In the second variant, the specified technical result is achieved by means of a method for testing the specified system, which includes the following actions: installing S _K in the first gas chamber and installing S _cp in the second gas chamber, connecting the controller to the specified sensors; - registration of the fact of the system’s operation in conditions of the absence of the influence of background gases on S _cp by heating the model element in the first chamber and/or determining threshold concentrations by dosing the model gas into the first chamber;

- registration of the fact that the system does not operate when dosing model gas into both chambers by filling the first and second chambers with background or model gas or determining the threshold concentrations for the system to operate by separately dosing model gas into the first and second chambers.

In this case, heating of the model element may include heating of a thermally activated gas-emitting material, preferably included in the composition of a thermally activated gas-emitting sticker, preferably multiple-action, installed on the controlled element in a gas chamber with a control sensor.

The controller can also be combined with one of the sensors. In this case, such a sensor combined with the controller is installed in one of the gas chambers, and the other sensor, installed in another gas chamber, is connected to the controller via wired or wireless communication.

The specified method provides a clear, regulated check of the system’s compliance with the conditions and algorithms described in the first object of the claimed group of inventions, for its further use in detecting overheating of electrical equipment elements.

In the third variant, the specified technical result is achieved through a method for automatically detecting overheating of electrical equipment elements, including:

- the placement of the system according to the first variant, in which at least one gas sensor S _K is installed inside the controlled zone; at least one gas sensor S _cp is installed outside the controlled zone; the controller is installed in an arbitrary location and communicates with at least two gas sensors, including at least one SK and at least one S _cp , wired or wireless, and can additionally communicate with another device; processing the overheating notification generated by the controller with subsequent issuance of an information message and/or transmission of data to another device.

The monitoring sensor (S _K ) can be installed inside the electrical installation near the monitored elements of electrical equipment, i.e. inside the monitored zone, in such a way as to register the products released during overheating of the monitored elements of electrical equipment or the thermally activated gas-emitting materials installed on them, and the comparison sensor S _cp can be installed in the external zone, i.e. outside the monitored zone, but near it, in such a way as to determine the concentration of background gases in the absence of products released during overheating of the monitored elements or the thermally activated gas-emitting materials installed on them. The comparison sensor can also be placed in another part of the electrical installation. It is permissible to install the comparison sensor in the monitored zone, in a place where the concentration of the signal gas will be minimal. For example, in the place of air inflow or in the lowest part of the installation. The possibility of such installation of the comparison sensor is due to the fact that the products released during overheating of the monitored elements of electrical equipment or the thermally activated gas-emitting materials installed on them have a temperature higher than the ambient temperature and rise upward.

In a particular case, the controller generates a notification about overheating of the controlled element and/or transmission of information about such overheating to another device when at least one S _cp is affected by products released during overheating of the controlled elements of electrical equipment or thermally activated gas-emitting materials installed on them. In other words, in this case, the comparison sensor simultaneously performs the function of a monitoring sensor, but for the elements of that compartment of the electrical installation (controlled zone) in which it is installed.

If the controller is combined with one of the gas sensors, it is placed in accordance with the location of this gas sensor, while the remaining sensors of the system communicate with it via wired or wireless communication. In the case of a separately made controller that communicates with all sensors of the system via wired or wireless communication, its place placement does not affect the operation of the system according to the invention. It is noted that it is recommended to install the controller in a place convenient for installation and maintenance during the operation of the system.

The group of inventions, in particular cases, is intended to detect overheating of contacts and contact connections of closed electrical equipment, including contact connections of electrical panels, complete distribution devices, low-voltage complete devices, boxes of the distribution block of the beginnings of windings. Also, the group of inventions can be intended to detect overheating of insulating materials of electrical equipment elements, including cable joints, as well as to prevent fires and detect defects in insulating materials of electrical equipment elements that occur as a result of the passage of arc discharges.

Brief description of the drawings

The group of inventions will be better understood from the description, which is not limiting in nature and is given with reference to the accompanying drawings, which show:

Fig. 1 - A system for automatically detecting overheating of electrical equipment elements, including a monitoring gas sensor S _K , installed inside the controlled zone near the controlled element of electrical equipment, a comparison gas sensor S _cp , installed in the external zone, outside the controlled zone, and a controller connected to both sensors by wired (a) and wireless (b) communication.

Fig. 2 - A system for automatically detecting overheating of electrical equipment elements, including a monitoring gas sensor S _K , installed inside a monitored zone near a monitored element of electrical equipment, a comparison gas sensor S _cp , installed in an external zone, outside the monitored zone, and a controller connected to both sensors by wire (a) and wireless (b) communication, wherein the monitored element additionally contains a thermally activated gas-emitting material (TGM). Fig. 2 shows a special case using a thermally activated gas-emitting sticker as a TGM.

Fig. 3 - Automatic detection system for overheating of electrical equipment elements, including a monitoring gas sensor S _K , placed into the first gas chamber (a) or into a gas chamber containing a heating element with a TGM (b), a comparison gas sensor S _cp placed in the second gas chamber, and a controller connected to both sensors by wire communication. Fig. 36 shows a special case using a thermally activated gas-emitting sticker as a TGM.

Fig. 4 - System for automatic detection of overheating of electrical equipment elements, including a monitoring gas sensor S _K , installed inside the controlled zone near the controlled element of electrical equipment, several comparison gas sensors S _cp n , installed in the external zone, outside the controlled zone in different places, and a controller connected to all sensors by wire (a) and wireless (b) communication. Fig. 4 shows a special case with three comparison sensors (n = 3).

Fig. 5 - A system for automatically detecting overheating of electrical equipment elements, including several monitoring gas sensors S _K m, each of which is installed inside a separate monitored zone near the monitored electrical equipment elements, several comparison gas sensors S _cp n, installed in the external zone, outside these monitored zones, and a controller connected to all sensors by wire (a) and wireless (b) communication. Fig. 5 shows a special case with three monitoring sensors (w = 3) and three comparison sensors (n = 3).

Fig. 6 - A system for automatically detecting overheating of electrical equipment elements, including a monitoring gas sensor S _K , installed in the upper part inside the controlled zone near the controlled element of electrical equipment, a comparison gas sensor S _cp , installed in the lower part inside the controlled zone, remotely from the controlled element, and a controller connected to both sensors by wired (a) and wireless (b) communication.

Fig. 7 - Schematic graph of the dependence of the intensity I of the signal recorded by the gas sensor on the parameter X of the gas mixture separately for background gases, products released during overheating of the controlled elements of electrical equipment, and gases released during overheating of thermally activated gas-emitting materials installed on the controlled elements of electrical equipment (a) and in generalized form (b). Fig. 1 shows a system for automatically detecting overheating of electrical equipment elements, placed on electrical equipment in such a way that the monitoring gas sensor S _K 5 is located in the controlled zone 1, in the immediate vicinity of the controlled element of electrical equipment 2, to ensure the possibility of registering products 4 released during overheating 3 of this element, and the comparison gas sensor S _cp 6 is located in the external zone outside the controlled zone 1, outside the electrical equipment so as to register background gases without registering products 4 released during overheating 3 of the controlled element 2, wherein both sensors are connected to the controller 7 by a wired (Fig. 1a) or wireless (Fig. 16) link 10 or 11, respectively (system design options).

Fig. 2 shows a system for automatically detecting overheating of electrical equipment elements, placed on electrical equipment in such a way that the monitoring gas sensor S _K 5 is located in the controlled zone 1, in the immediate vicinity of the controlled element of electrical equipment 2, on which the TGM 8 is located, to ensure the possibility of registering products (gases) 4 released during the activation of this material 8 as a result of overheating 3 of this element, and the comparison gas sensor S _cp 6 is located in the external zone outside the controlled zone 1, outside the electrical equipment so as to register background gases without registering products 4 released during the activation of material 8 as a result of overheating 3 of the controlled element 2, wherein both sensors are connected to the controller 7 by a wired (Fig. 2a) or wireless (Fig. 2b) link 10 or 11, respectively (system embodiments). Fig. 2 shows a special case in which a thermally activated gas-emitting sticker is used as the TGM.

Fig. 3 shows a system for automatically detecting overheating of electrical equipment elements, installed in gas chambers to illustrate the method of using and testing this system, in such a way that the monitoring gas sensor S _K 5 is placed in the first gas chamber 9 (Fig. 3a), or in the first gas chamber 9 containing a controlled heating element 2 on which a TGM 8 is located (in Fig. 36, as an example of using a TGM, a thermally activated gas-emitting sticker is shown), which emits gases 4 as a result of overheating 3, for the registration of which the sensors are configured, and the gas The comparison sensor S _cp is placed in the second gas chamber 9, while both sensors are connected to the controller 7 by a wire connection 10 (system design options).

Fig. 4 shows a system for automatically detecting overheating of electrical equipment elements, placed on electrical equipment in such a way that the monitoring gas sensor S _K 5 is located in the controlled zone 1, in the immediate vicinity of the controlled element 2, in order to ensure the possibility of registering the products 4 released during overheating 3 of this element, three comparison gas sensors S _cp lS _cp 3 6 are located in the external zone outside the controlled zone 1, outside the electrical equipment in different places (for example, from above, below and on the side, as shown in Fig. 4) so as to register background gases without taking into account the content of the products 4 released during overheating 3 of the controlled element 2, wherein all sensors are connected to the controller 7 by wire (Fig. 4a) or wireless (Fig. 4b) communication 10 or 11, respectively (versions of the system with three comparison sensors and one monitoring sensor).

Fig. 5 shows a system for automatically detecting overheating of electrical equipment elements, located on electrical equipment consisting of three closed controlled zones EO1-EOZ, in such a way that the monitoring gas sensors S _K 1-S _K 3 5 are located in the controlled zones 1, in the immediate vicinity of the controlled elements 2 inside the corresponding closed controlled zones 1 EO1-EOZ to ensure the possibility of registering the products 4 released during overheating 3 of these elements, three comparison gas sensors S _cp lS _cp 3 6 are located in the outer zone outside the controlled zones 1, outside the closed volumes of the electrical equipment so as to register background gases without taking into account the content of the products 4 released during overheating 3 of the controlled elements 2, wherein all sensors are connected to the controller 7 by a wired (Fig. 5a) or wireless (Fig. 5b) link 10 or 11, respectively (versions of the system with three comparison sensors and three monitoring sensors).

Fig. 6 shows a system for automatically detecting overheating of electrical equipment elements, placed on electrical equipment in such a way that the monitoring gas sensor S _K 5 is located in the upper part inside the controlled zone 1, in the immediate vicinity of the controlled element 2, to ensure the possibility of registering products 4 released during overheating. 3 of this element, and the comparison gas sensor S _cp 6 is located in the lower part inside the controlled zone 1 so as to register background gases without registering products 4 released during overheating 3 of the controlled element 2, while both sensors are connected to the controller 7 by wire (Fig. 6a) or wireless (Fig. 6b) communication 10 or 11, respectively (system design options).

Fig. 7a is a schematic representation of an approximate graph of the dependence of the intensity (I) of the signal recorded by the gas sensor on the parameter of the gas mixture (X) separately for background gases (dashed line, a), products released during overheating of the controlled elements of electrical equipment (solid line, b), and signal gases (bold line, c). The graph shows the possible overlap of the signal characterizing the content of products released during overheating of the controlled elements with signals characterizing the content of background gases, even in the region of maximum intensity I _max , as well as the preferred location of the signal characterizing the content of gases released from thermally activated gas-emitting materials relative to the signals characterizing the content of background gases. Fig. 7b is a schematic representation of an approximate graph of the dependence of the intensity (I) of the signal recorded by the gas sensor on the parameter of the gas mixture (X) in generalized form.

Implementation of the claimed group of inventions

The group of inventions may be intended to detect overheating of conductive elements, cables and cable joints, contacts and contact connections, as well as other elements of closed electrical equipment, including contact connections of electrical panels, complete switchgear units, low-voltage complete devices, boxes of the distribution block of the beginning of windings. The group of inventions may also be intended to detect overheating of insulating materials of electrical equipment elements, including cable joints, to prevent fires of electrical equipment, and to detect defects in insulating materials of electrical equipment elements that arise as a result of the passage of arc discharges.

In accordance with the first version of the claimed group of inventions, the system for automatically detecting overheating of electrical equipment elements (Fig. 1-2), includes: a gas sensor S _K 5, intended for detecting gases 4, released during heating 3 of the controlled element 2 or thermally activated gas-emitting materials 8 installed on it; a gas sensor S _C p 6, intended for determining the concentration of background gases in the air near the controlled zone 1; a controller 7, made with the possibility of connecting to at least two gas sensors, including at least one monitoring sensor S _K 5 and at least one comparison sensor S _C p 6, and generating a notification about overheating and/or transmitting information about such overheating to another device.

Sensors with different types of sensitive elements and based on the detection of different air parameters can be used as gas sensors in the claimed group of inventions. In particular, such sensors can be semiconductor, thermocatalytic, conductometric, electrochemical, optical and others.

If there are several comparison sensors and several monitoring sensors in the system, their operating principle may differ. However, in preferred embodiments, the condition for the controller to generate an overheating notification is the registration of the effect on the monitoring sensor of products released during overheating of the controlled element or thermally activated gas-emitting materials installed on it, taking into account the concentration of background gases detected by the comparison sensor, which has a sensitive element of the same type as the monitoring sensor.

The type of sensors, their sensitivity and quantity are determined based on the specific task, the solution of which is aimed at using the claimed group of inventions, the type of electrical equipment being monitored and other factors. It is most preferable to use in the system according to the claimed group of inventions semiconductor sensors, the sensitive element of which is designed with the ability to detect gases released during heating of the following types of insulating materials, including, in particular, cross-linked polyethylene (PE), polyvinyl chloride (PVC), rubber, silicone, epoxy resin, as well as during overheating of thermally activated gas-emitting stickers installed on the controlled elements, due to the higher sensitivity of such sensors to the products of thermal destruction of insulating materials materials of controlled elements of electrical equipment, lower energy consumption and longer service life compared to other sensors

The system may additionally include thermally activated gas-emitting materials, primarily of multiple action, included in the composition of products or coatings installed or applied to the controlled elements.

Gas sensors 5-6 according to the claimed group of inventions should preferably have the following technical characteristics: the minimum threshold concentration of the gases being monitored is 100 ppm for freons and CO, 50 ppm for alkanes (CnHgp+g) and alkenes (CnHgp) with n<4; they are structurally implemented as a single module; the supply voltage of the sensors is 5 V DC; the service life is at least 10 years from the date of manufacture.

To detect overheating of electrical equipment elements not covered with insulating or other materials subject to thermal destruction or other types of decomposition when the temperature increases, the system may contain special thermally activated gas-emitting materials (TGM), preferably multiple-action, which emit signal gases when heated above a threshold temperature (Fig. 2). Such materials may be included in the composition of heat-activated gas-emitting stickers 8, clips or cambrics, as well as heat-activated paints, varnishes or coatings, and may be installed or applied to monitored non-insulated elements of electrical equipment 2, overheating 3 of which results in a violation of the integrity of the TGM layer 8 and the release of the gas 4 contained therein, for the detection of which the monitoring sensor 5 is configured. The advantage of using such materials is that, as a rule, they contain gases that are rarely found in the air under normal conditions even near such sources of foreign gases as large chemical plants, busy highways, etc. In addition, TGMs have the ability to repeatedly release gas in repeating heating/cooling cycles, which ensures the possibility of multiple detection of overheating of electrical equipment elements without replacing the system or its individual parts.

The claimed group of inventions primarily uses heat-activated gas-emitting stickers of multiple action, produced by the company ThermoElectrika LLC and made of a polymer composite material containing a continuous phase formed thermosetting polymer, the pores of which are filled with a sulfur-containing odorant or freon. In this case, the system sensors are tuned to selective gases released from these thermally activated gas-emitting stickers. The advantage of these stickers is that when heated once to a temperature exceeding the threshold, only part of the pores filled with the odorant opens and gas is partially released. The ability of these stickers to repeatedly release signal gases in repeated cycles of heating to the threshold temperature and cooling ensures multiple triggering of the system according to the claimed group of inventions.

In most cases, TGM 8 must have the following set of technical characteristics: signal gas content - not less than 50%; response temperature of 80-150 °C; the signal gas emitted from the TGM has a hazard class of not lower than the 4th and an electric strength of not less than 15 kV/cm; the threshold sensitivity of the sensors to the signal gas emitted from the TGM is not less than 100 ppm; TGM do not emit harmful substances and are classified as low-hazard in terms of impact on the human body; retain their characteristics after five-fold cooling to the minimum operating temperature with subsequent heating to a temperature 10 °C below the response temperature. In particular, heat-activated gas-emitting stickers, in addition to the above characteristics, may also have adhesion of the adhesive layer to stainless steel of not less than 15 N/25 mm and resistance of the adhesive layer under the influence of various oils, fats, water, acids, salts, alkalis, solvents; have an electrical strength of at least 18 kV/mm; a minimum bending radius at 24 °C of 2 mm, at 0 °C of 12 mm; a service life of at least 10 years from the date of manufacture.

In a preferred embodiment, S _K 5 and S _cp 6 are configured to detect gases belonging to classes of compounds selected from the list: halocarbons, hydrogen halides, halohydrocarbons, alkenes, alkanes, mercaptans, acids or mixtures thereof, preferably gases selected from the list: carbon tetrafluoride, tetrafluoroethylene, tetrachloroethylene, trifluorochloromethane, chloroform, dichloromethane, methyl chloride, methyl bromide, trifluoromethane, ethyl chloride, vinyl chloride, hydrogen fluoride, hydrogen chloride, ethylene, propylene, butadiene, isoprene, methane, ethane, butane, hexane, methyl mercaptan, dimethyl sulfide, ethyl mercaptan, diethyl sulfide, nitric acid, nitrous acid or mixtures thereof. For reliable and accurate operation of the system, it is necessary and sufficient to have two sensors (Fig. 1): in this case, one of them is a monitoring sensor (5, S _K ) and is installed inside the monitored zone 1 near the monitored elements of electrical equipment 2 in such a way as to determine the concentration of products 4 released during overheating 3 of the monitored elements of electrical equipment 2, and the other sensor is a comparison sensor (6, S _cp ) and is installed outside the monitored zone in such a way as to determine the concentration of background gases without monitoring the products 4 released during overheating 3 of the monitored elements 2. In the simplest case, when using a system with one S _cp and one S _K , the analysis of the signals coming to the controller from the monitoring sensor and the comparison sensor is carried out by comparing their difference, calculated as the difference in the signal values or according to more complex algorithms, including with a predetermined threshold value.

However, the claimed system may contain more than one S _cp 6, and/or more than one S _K 5 (Fig. 4-5). If the system contains more than one S _cp 6, the generation of a notification about overheating of the controlled element and/or the transmission of information about such overheating to another device may occur taking into account the average value of gas concentrations determined by all or some S _cp 6, with the same or different contribution of the content of background gases, the concentration of which is determined by each individual S _cp 6. If the system contains more than one S _K 5, the generation of a notification about overheating 3 of the controlled element 2 and/or the transmission of information about such overheating to another device may occur when the average concentration of gases detected by all or some S _K 5, with the same or different contribution of the excess concentration of products 4 released during overheating 3 of the controlled elements 2 of the electrical equipment or thermally activated gas-emitting materials 8 installed on them, detected by each individual S _K 5, exceeds specified threshold values.

The system according to the present group of inventions can function without a given threshold concentration value. In this case, the controller can also take into account the values of gas concentrations obtained from all or some S _cp , but the comparison of data obtained from the monitoring sensor will not occur with a fixed threshold value, but, for example, with a dynamic average value, which is calculated at each moment in time and depends in a certain way on the concentrations recorded by the comparison sensors. In another embodiment of the claimed system, the baseline characterizing the background gas content is determined by the value of long-term running average values of signals received from the monitoring sensor, and the current content of signal gases in the controlled area is determined as a short-term running average value of the monitoring sensor signals. Preferably, the time interval for which the long-term running average is calculated is more than 5 minutes, and the time interval for calculating the short-term running average is less than 1 minute. In this case, the comparison sensor allows not only to cut off false alarms caused by a change in the concentration of background gases, but also to correct the optimal time interval of running average values and adjust adaptive thresholds.

Other possible algorithms for the operation of the system for the claimed group of inventions are discussed in more detail below.

Regardless of the implemented algorithm for generating an overheating notification, the controller 7 is preferably designed with the ability to take into account the concentration of background or signal gases that have affected the sensors 5-6 during the previous period of time.

The comparison sensor 6 can also be designed with the ability to register products 4 released during overheating of 3 controlled elements 2 of electrical equipment or thermally activated gas-emitting materials 8 installed on them. In this case, the controller 7 can also generate a notification about overheating 3 of the controlled element 2 and/or transmit information about such overheating to another device.

Preferably, the comparison sensor is designed with the ability to take into account the current content of background gases recorded in the range of 10-10000 ppm.

In special cases, the system according to the claimed group of inventions can be additionally equipped with one or more temperature sensors, on the basis of which the controller can also generate an alarm notification about overheating. The presence of temperature sensors allows to further increase the reliability of detecting overheating of electrical equipment elements or to determine the fact of fire.

All sensors 5-6 present in the system are connected to the controller 7 using wired 10 or wireless 11 communication. Also, the controller 7 can be connected to one of the gas sensors by combining and linked to the rest sensors of the system via wired or wireless communication. Thus, the controller 7 is designed with the ability to generate an overheating notification upon receipt and processing, using a set of algorithms, of data from all sensors present in the system.

Depending on the task set, the controller 7 can issue both a notification informing about overheating of the controlled elements 2 of the electrical equipment, in the form of a sound, light, graphic or other notification, and a control notification, for example, to disconnect the emergency equipment from the network. The controller 7 can also transmit a notification about overheating of the controlled elements of the electrical equipment to an external receiving device and/or provide a combined notification, for example, transmit a notification about overheating of the controlled elements of the electrical equipment to an external receiving device and a control notification to the control elements of the controlled electrical equipment. The type of notification used about overheating of the controlled elements is determined on the basis of the technical documentation of the controlled electrical equipment, as well as the ease of use of the system.

Controller 7 used for the declared system may preferably have the following technical characteristics: the presence of an RS-485 digital communication line interface; the presence of the Modbus RTU digital communication line protocol; it has the following control and indication elements: buttons for setting parameters, a digital indicator for displaying the device address and setting parameters, LEDs for indicating the status of connected sensors; the supply voltage is from 12 to 28 V DC (nominal value - 24 V); it has EMC compatibility in accordance with GOST for residential, commercial and industrial areas with low power consumption or for substations and power plants; the enclosure protection rating is at least IP 20; the presence of a discrete output "Alarm"; the service life is at least 10 years from the date of manufacture.

The controller 7 can be additionally configured with the possibility of generating a notification about overheating 3 of the controlled element 2 and/or transmitting information about such overheating to another device upon detection of S _K 5 products 4 released during overheating of 3 of the controlled elements 2 of the electrical equipment or thermally activated gas-emitting materials 8 installed on them, in a concentration higher than a specified limit value, regardless of the current concentration of background gases recorded by S _cp 6. In preferred embodiments, the claimed system additionally has a self-diagnostic function informing about the need to replace the sensitive element of one or more sensors. The need to replace the sensitive element may be due, in particular, to its degradation over time or the end of the established service life.

Taking into account the system features disclosed in the description, it is worth noting additionally that the content of both signal and background gases is recorded by sensors 5-6 by changing certain parameters of the gas-air environment, the values of which characterize the concentration of these gases, but do not determine its numerical absolute value. As was said above, the comparison of the parameters obtained with S _K and S _cp is carried out depending on the system settings and, in the simplest case, can be a comparison of the difference in the values of these parameters with a specified threshold value. In a more complex case, the concentrations of signal and background gases are compared with the threshold value using mathematical algorithms, and in the case of using several comparison sensors, the threshold value may not be set, and the parameters obtained with S _K 5 will be analyzed by controller 7 in the dynamic mode by their inclusion or non-inclusion in the set of values formed by the dispersion or standard deviation from the average value obtained from S _cp 6.

The system may use the following algorithms when generating a notification of overheating 3 of the controlled element 2 and/or transmitting information about such overheating to another device: calculating the running average value from each sensor for a specified period of time; adjusting the reference (zero) value; determining the reduced running average value as the difference between two running average values obtained from one sensor for two different periods of time, preferably a short period of less than one minute and a long period of more than 5 minutes; comparing the reduced running average value with the threshold value and generating an overheating notification if it is exceeded; determining the average value of the signal received from different sensors by averaging the reduced running average values; comparison of the difference in the reduced running average values of the signals from the comparison sensor and the monitoring sensor, including those calculated over different time periods, with a given threshold value; determination of the growth rate of the reduced running average value and its comparison with the set threshold value; comparison of the signal received from the monitoring sensor with the set threshold value; determination of the growth rate of the difference in the reduced running average value of the signal of the monitoring sensor and the comparison sensor and its comparison with the set threshold value; determination or change of threshold values based on the analysis of the values of signals received from the sensors during operation. adaptive response threshold

Let's look at them in more detail:

где - бегущее среднее,

- мгновенное значение сигнала,

- время, за которое происходит усреднение, . количество точек, по которым происходит усреднение. 1. Calculation of the running average value from each sensor for a given period of time. In this case, the system forms a baseline against which the current concentration determined by the monitoring sensors 5 is compared, based on the running average values of the concentrations determined by each sensor for a given period of time. The baseline can be obtained by averaging the data of the running average values using a set of mathematical operations. The running average is calculated at each moment in time using the formula:

where is the running average,

- instantaneous value of the signal,

- the time during which averaging occurs, the number of points over which averaging occurs.

2. Correction of the reference (zero) value. Due to the fact that each sensor 5-6, depending on external conditions and manufacturing features, may have slightly different sensitivity and aging rate, in order to maintain the initial high sensitivity and response accuracy of the system, the sensors used in it must be made with the ability to continuously smoothly take these features into account. Correction of the reference (zero) value, the drift of which occurs due to degradation of the sensitive element, changes in temperature and humidity of the environment, as well as due to the possible presence of foreign gases in the atmosphere, is performed in order to take into account slow processes that lead to a change in the characteristics of the sensor and are obviously not associated with the release of signal gas or products of thermal destruction of insulating materials. The reference value is adjusted by calculating the running average over a relatively long period of time, which is more than 5 minutes.

3. Definition of the reduced running average value as the difference between two running average values obtained from one sensor over two different time intervals. At each moment in time, the system compares two main parameters: the long-term running average (reference value) obtained from the gas sensor over a time interval preferably exceeding 5 minutes and characterizing the background concentration of gases, and the short-term running average obtained from the same gas sensor over a time interval preferably not exceeding 1 minute and characterizing the current concentration of signal gases in the controlled area. The short-term running average allows smoothing out signal fluctuations occurring over short time intervals and associated with possible electromagnetic interference. The reduced running average is defined as the difference between the two obtained values: the short-term and long-term running averages.

4. Comparison of the reduced running average value with the threshold value and generation of an overheating notification if it is exceeded. The short and long running average values are calculated according to the algorithm given in paragraph 1. The reduced running average value of concentration is obtained using two values: the short and long running averages - as a result of their difference or is calculated using a more complex mathematical algorithm. Generation of an overheating notification occurs when the reduced running average value exceeds a certain specified threshold value.

5. Determining the average value of the signal received from different sensors by averaging the given running average values. The system determines the short and long running average values according to the algorithm given in point 1, however, if there are several monitoring sensors 5 and/or several comparison sensors 6, the obtained data are averaged using a set mathematical operations. To generate an overheating notification, the average values are compared by calculating their difference or using more complex algorithms.

6. Comparison of the difference in the reduced running average values of the signals from the comparison sensor and the monitoring sensor, including those calculated for different time intervals, with a given threshold value. Short and long running average values are calculated for all monitoring and comparison sensors according to the algorithm given in paragraph 1. Data obtained from Sep 6 are taken into account to exclude false alarms. Comparison can be carried out for a certain period of time, the duration of which is determined experimentally and takes into account the delay for the entry and venting of gas from the controlled area, characterizing the degree of leakage of electrical equipment.

7. Determining the growth rate of the reduced running average value and comparing it with the set threshold value. The reduced running average value is calculated similarly to the algorithm given in p.3. The growth rate of the reduced running average value of the signal gas concentration recorded by gas sensor 5-6, in the absence of overheating of the controlled elements, must be equal to zero. In the event of overheating 3, leading to the release of products 4, for the registration of which gas sensor 5 is configured, the value of the growth rate of the reduced running average will increase abruptly, which will lead to the formation of an overheating notification by controller 7, even if the threshold concentration has not been reached.

8. Comparison of the signal received from the monitoring sensor with the set threshold value. The system can generate a notification about overheating 3 in the event that the monitoring sensor 5 registers a sharp significant increase in the concentration of products 4 (exceeding the threshold value several times) released during overheating 3 of the monitored elements 2 of the electrical equipment or the thermally activated gas-emitting materials 8 installed on them, and exceeding the set threshold values without taking into account the concentration of background gases determined by the comparison sensor 6. For example, such a situation can arise during the burning of an electric arc or the ignition of insulating materials. 9. Determining the growth rate of the difference between the reduced running average value of the signal of the monitoring sensor and the comparison sensor and comparing it with the set threshold value. The reduced running average values are calculated for all monitoring sensors 5 and all comparison sensors 6 similarly to the algorithm given in paragraph 4. One of the criteria for generating an overheating notification 3 is a comparison of the growth rate of the reduced running average value of the signal gas content recorded by S _K and S _cp . When an external background source of signal gases occurs, the growth rate of the reduced running average values G _K and G _cp recorded by sensors S _K and S _cp respectively will either be equal (in the case of a low degree of tightness of the electrical installation or high diffusion of signal gases) or G _K < G _cp (if the electrical installation is sufficiently tight and the diffusion of foreign gases into the electrical installation is slow) and the system will not be triggered. If G _K > G _cp , then controller 7 will generate a notification about overheating 3, which will indicate a sharp increase in the concentration of signal gases 4 inside the electrical installation as a result of overheating 3 of the controlled elements 2.

10. Determining or changing threshold values based on the values of signals received from sensors during operation. The system for automatically detecting overheating 3 of elements of electrical equipment 2 is designed with the ability to determine and calibrate the maximum concentration of gases 4, for the detection of which sensors 5-6 are configured, at which the system is triggered, using the method for testing the system according to the claimed group of inventions. Threshold values can be set by the controller 7 either manually when installing the system, or fixed in advance when manufacturing the system, or be adaptive and dynamically changing depending on the operating conditions of the system.

11. Adaptive response threshold. During operation, the threshold value can be automatically adjusted in a given range of values depending on the magnitude of fluctuations in foreign gases over a long period of time (more than 1 day). In such an algorithm, when the sensor is initially turned on, the threshold value is taken to be equal to some initial value. Then, during a given time interval, the maximum concentration value is recorded by the sensor or group of sensors, but which does not cause the system to operate. Based on the results of comparing the value of this the maximum concentration with the threshold value is decided to increase or decrease the threshold value.

Another criterion for the system to operate and generate an overheating notification is a comparison of the absolute values of the signals characterizing the content of products released during overheating of the monitored elements or thermally activated gas-emitting materials installed on them, and those detected by S _K 5 and S _cp 6. If C _avg , the maximum value of the signal characterizing the content of background gases and registered by S _cp 6 outside the monitored zone, exceeds C _k , the value of the signal characterizing the content of the same gases and registered by S _K 5, this will mean that the cause of these gases lies outside the electrical installation and the system will not operate. Similarly, the system will not operate if C _k and C _avg are equal, regardless of their absolute value, which will indicate an increase in the content of signal gases 4 due to the external background with a low degree of leakage in the protected zone or high diffusion of these gases. Controller 7 will generate an overheating notification 3 only if C _k > C _avg , i.e. when the concentration of signal gases 4 inside the controlled zone 1 exceeds their background concentration in the outer zone, which will indicate that the source of their occurrence is heated controlled elements 2.

In this case, controller 7 can be configured in such a way as to compare the data received from S _K and S _cp both in real time and with a certain time delay, determined experimentally and taking into account the delay in the entry and evaporation of gas from the controlled zone, characterizing the degree of leakage of the electrical equipment.

The system may contain both more than one monitoring sensor and more than one comparison sensor. Let us consider a system with one monitoring sensor and n comparison sensors (Fig. 4, n = 3). In this case, the minimum concentration of products 4, released during overheating of 3 controlled elements 2, (C _c ), determined by the monitoring sensor 5, sufficient for the controller 7 to generate an overheating notification, may depend on the current concentration of background gases, determined by all S _cp 6, either equally or according to formula (1), taking into account the contribution of each comparison sensor separately:

C _K = (ki*Cc _P l + k ₂ *C _cp 2 + ... + kn*C _cp n)/n, (1) where k _n are the coefficients of gas distribution non-uniformity, determined experimentally for each of the n sensors, taking into account the features of their locations, for example, depending on the degree of leakage of the controlled electrical equipment 1 or on the distance of the comparison sensor 6 from the monitoring sensor 5. In the absolute majority of cases, k lies within [0;1], preferably selected from the group: 0; 0.5; 1. Thus, depending on the system settings, the signals received by the controller 7 from individual comparison sensors 6 can either be completely taken into account (k = 1) , are either partially taken into account or completely ignored (k = 0). In particular, the system can be configured in such a way that the controller does not take into account the extreme values of the background gas concentration determined by the comparison sensors, i.e. in this case the coefficient k will not be fixed and can take a zero value depending on the data received from S _cp .

Let us consider a system with ш monitoring sensors and n comparison sensors (Fig. 5, n = 3, m = 3). Such a system can, for example, be installed in several adjacent electrical panels 1, with at least one S _K 5 installed inside each panel, and at least one S _cp 6 mounted, for example, on the outer surface of the panel 1. Then the minimum concentration of products 4, released during overheating of 3 controlled elements 2, (C _k t), determined by each monitoring sensor, sufficient for the formation of an overheating notification by the controller 7, can also depend on the current concentration of background gases registered by all S _cp 6, according to formula (1). With the value of all coefficients k _n = 1, the contribution of each comparison sensor individually to the limit value of C _k t will be equal.

To test the specified system, the following method can be implemented, including the following actions: installing S _K in the first gas chamber and installing S _cp in the second gas chamber, connecting the controller to the specified sensors;

- registration of the fact of the system’s operation in conditions of the absence of the influence of background gases on S _cp by heating the model element in the first chamber and/or determining threshold concentrations by dosing the model gas into the first chamber; - registration of the fact that the system does not operate when dosing model gas into both chambers by filling the first and second chambers with background or model gas or determining the threshold concentrations for the system to operate by separately dosing model gas into the first and second chambers.

Heating of the model element may include heating of a heat-activated material in a gas chamber with a control sensor.

Carrying out testing of the system in the specified manner ensures a clear, regulated check of the system’s compliance with the conditions and algorithms described in the first object of the claimed group of inventions, as well as for its further use in identifying overheating of electrical equipment elements.

The implementation of the method in particular cases can be presented as follows: S _K 5 (Fig. 3a) is placed in the first gas chamber 9 filled with a neutral gas, for example, nitrogen, and S _cp 6 is placed in the second gas chamber 9 filled with the same neutral gas. Both sensors are connected to the controller, in particular, by wire communication, and the absence of actuation of the system in this state is recorded. Then, a model gas simulating the signal gas is dosed into the first gas chamber, and the minimum concentration of this model gas is recorded, at which the system is triggered and the controller generates a notification about overheating, thereby determining the threshold value.

After the installation for testing the system has returned to its initial state, the model gas simulating the signal gas is dosed in a known concentration C _cp , not exceeding the threshold concentration at which the system may be triggered, into the second gas chamber 9 and the absence of the system being triggered is recorded. Then, the same model gas is dosed into the first gas chamber in a concentration not exceeding C _cp , and the absence of the system being triggered is recorded. With a further gradual increase in the content of the model gas in the first chamber 9, the minimum gas concentration is recorded at which the system is triggered and the controller generates an overheating notification. Using the obtained value, the threshold gas concentration at which the system is triggered is calculated. In another embodiment of the method for testing the system according to the claimed group of inventions, a heating element 2 is installed in the first gas chamber 9 filled with neutral gas, onto which a thermally activated gas-emitting sticker 8 is placed (used in this case as an article containing TGM), and S _cp 6 is placed in the second gas chamber 9 filled with the same neutral gas, but without the heating element 2 (Fig. 36). Both sensors are connected to the controller by wire communication and record the absence of actuation of the system in this state. Then the heating element 2 is heated to the activation temperature of the gas-emitting sticker 8 and the actuation of the system is recorded by registering the overheating notification issued by the controller 7, informing about the overheating of the electrical equipment elements.

After the installation for testing the system has returned to its initial state, a model gas simulating the signal gas is dosed into the second chamber 9 in a known concentration C _sr , not exceeding the threshold concentration at which the system may be triggered, and the absence of the system triggering is recorded. Then the heating element 2 is heated to the activation temperature of the gas-emitting sticker 8 and the triggering of the system is recorded by registering the overheating notification issued by the controller 7, informing about the overheating of the electrical equipment elements.

According to the claimed group of inventions, the system for automatically detecting overheating of electrical equipment elements is used in accordance with the following method: placing the system according to the first variant, in which at least one gas sensor S _K is installed inside the controlled zone; at least one gas sensor S _cp is installed outside the controlled zone; the controller is installed in an arbitrary location and communicates with at least two gas sensors, including at least one S _K and at least one S _cp , by wired or wireless communication, and can also additionally communicate with another device; processing the overheating notification generated by the controller, followed by issuing an information message and/or transmitting data to another device. The method may also implement algorithms, in particular, disclosed in this application when describing the system. In particular, the controller 7 may additionally generate a notification about overheating 3 when one of the sensors 4 detects gases released during heating 3 of the controlled elements 2 or thermally activated gas-emitting materials 8 installed on it, in a concentration higher than a specified limit value, regardless of the content of background gases detected by at least one other sensor.

In a preferred embodiment, detection of overheating 3 of controlled elements 2 of electrical equipment occurs by recording signal gases released from thermally activated gas-emitting materials 8, primarily of multiple action, included in the composition of products or coatings installed or applied to controlled elements 2.

Let us consider specific cases of the implementation of the stated group of inventions.

Examples.

Example 1.

The system according to the claimed group of inventions is installed as follows: the semiconductor sensor S _K is placed in the first hermetically sealed gas chamber with a volume of 100 l, filled with nitrogen, and containing a heating element covered with an insulating material. The semiconductor sensor S _cp is placed in the second hermetically sealed gas chamber with a volume of 100 l, filled with nitrogen, but without a heating element. Both sensors are connected to the controller by a wired connection and the absence of actuation of the system in this state is recorded. Then the heating element is heated to a temperature of 100 °C, at which thermal destruction of the insulating materials begins, but no ignition occurs. The actuation of the system is recorded by registering a notification issued by the controller, informing about overheating of the electrical equipment elements. In this example, the actuation of the system occurs due to the detection by the monitoring sensor of gases released as a result of heating of the model element, in the absence of the influence of background gases on S _cp .

Example 2.

The system according to the claimed group of inventions is installed as follows: the semiconductor sensor S _K is placed in the first sealed gas a 100-liter chamber filled with nitrogen. The semiconductor sensor S _cp is placed in a second hermetically sealed gas chamber with a volume of 100 liters filled with nitrogen. Both sensors are connected to the controller by a wired connection, and the absence of a system response in this state is recorded. Then, a model gas simulating signal gases is continuously dosed into the first gas chamber at a rate of 10 ppm/min. The system does not respond during the first five minutes (with a signal gas content of up to 50 ppm). The response of the system is recorded in the fifth minute by registering a notification issued by the controller informing about overheating of electrical equipment elements, and the content of the model gas in the first chamber at this moment is determined. The test is repeated three times, determining the average value of the threshold concentration, which in this example was 57 ppm. In this example, the system is triggered by the detection by the control sensor of model gases simulating gases released as a result of heating of the model element, in conditions of the absence of the influence of background gases on S _cp .

Example 3.

The system according to the claimed group of inventions is installed as follows: the semiconductor sensor S _K is placed in the first hermetic gas chamber with a volume of 100 l filled with nitrogen. The semiconductor sensor S _cp is placed in the second hermetic gas chamber with a volume of 100 l filled with nitrogen. Both sensors are connected to the controller by a wired connection and the absence of the system response in this state is recorded. Then, the model gas simulating the signal gas is simultaneously dosed into the second gas chamber, in which the comparison sensor is installed, in the amount of _{C cp} = 100 ppm. In this case, the system is triggered by the detection by the comparison sensor of model gases simulating the signal gases in a concentration exceeding the threshold value.

After this, a model gas simulating the signal gas (C _k ) is dosed into the chamber in which the control sensor is installed in a continuous mode at a rate of 10 ppm/min. The absence of system activation is recorded in the first 15 minutes, when the content of model gases in the first chamber did not exceed 150 ppm. After the content of model gases in the first chamber reaches 150 ppm, the activation of the system is recorded by registering the notification issued by the controller. This confirms the threshold concentration for the activation of the system, which in this case is equal to 50 ppm. In this case, the activation The system is controlled by the detection of model gases by the control sensor that simulate signal gases, taking into account the content of these same model gases recorded by the comparison sensor.

Next, in order for the system to exit the triggering mode, the gas chambers are ventilated and refilled with nitrogen, after which they begin to continuously dose the model gas simulating the signal gas at a rate of 50 ppm/hour until its actual content reaches 100 ppm. The change in the reference (zero) value of the sensor signal is recorded due to the implementation by the system of zero value drift algorithms and a low rate of increase in the concentration of the signal gas. Then 150 ppm of the model gas simulating the signal gas are simultaneously dosed into the first gas chamber, while the actual content of this gas in the first chamber was 550 ppm. The system's triggering is recorded by registering the notification issued by the controller. In this case, the possibility of multiple action of the system is realized.

Example 4.

The system according to the claimed group of inventions is installed as follows: the optical sensor S _K is placed in the first hermetically sealed gas chamber with a volume of 100 l, filled with nitrogen, and containing a heating element, on which a thermally activated gas-emitting sticker with an activation temperature of 100°C is placed. The optical sensor S _cp is placed in the second hermetically sealed gas chamber with a volume of 100 l, filled with nitrogen, but without a heating element. Both sensors are connected to the controller by wireless communication and the absence of actuation of the system in this state is recorded. Then the heating element in the first chamber is heated to a temperature of 100°C, at which thermal activation of the sticker and the release of signal gases from it begins. The actuation of the system is recorded by registering a notification issued by the controller, informing about the overheating of the electrical equipment elements. In this case, the actuation of the system occurs due to the detection by the monitoring sensor of gases released during the activation of the thermally activated gas-emitting material, in conditions of the absence of the influence of background gases on S _cp .

Next, the gas chamber is ventilated so that the system exits the trigger mode, refilled with nitrogen, and the heating element is cooled to room temperature. After this, the heating element is heated again to a temperature of 100°C and the triggering of the system is recorded. In this case, the possibility is realized multiple action system using thermally activated gas-emitting materials.

Example 5.

The system according to the claimed group of inventions is installed as follows: the semiconductor sensor S _K is placed in the first hermetically sealed gas chamber with a volume of 100 l, filled with nitrogen, and containing a heating element covered with an insulating material. The semiconductor sensor S _cp is placed in the second hermetically sealed gas chamber with a volume of 100 l, filled with nitrogen, but without a heating element. Both sensors are connected to the controller by a wired connection and the absence of actuation of the system in this state is recorded. Then, 500 ppm of a model gas simulating the background gas is dosed into both chambers for 10 hours at a rate of 50 ppm per hour. The absence of actuation of the system is recorded due to the implementation by the system of an algorithm taking into account the drift of the zero value. After this, the heating element installed in the chamber containing the monitoring sensor is heated to a temperature of 200 ° C, at which thermal destruction of the insulating materials occurs, but no ignition occurs. The system's activation is recorded by registering a controller-issued notification informing about overheating of electrical equipment elements. In this example, the system is activated by the detection by the control sensor of gases released as a result of heating of the model element, under conditions of the influence of background gases on both sensors, taking into account the zero value drift.

Example 6.

The system according to the claimed group of inventions is installed as follows: the semiconductor sensor S _K is placed in the first hermetically sealed gas chamber with a volume of 100 l filled with nitrogen. The semiconductor sensor S _cp is placed in the second hermetically sealed gas chamber with a volume of 100 l filled with nitrogen. Both sensors are connected to the controller by wire communication and the absence of the system response in this state is recorded. Then, 500 ppm of model gas simulating the signal gas is dosed into both gas chambers simultaneously for 10 hours at a rate of 50 ppm per hour. The absence of the system response is recorded due to the system implementing an algorithm that takes into account the rate of increase in the concentration of the signal gas. After this, the model gas simulating the signal gas is simultaneously introduced into the chamber containing the control sensor in an amount of 50 ppm. The response of the system is recorded by registering the signal issued by the controller. notification informing about overheating of electrical equipment elements. In this example, the system is triggered by the detection by the control sensor of a model gas simulating a signal gas, under conditions of a rapid increase in its concentration and taking into account its effect on the comparison sensor.

Example 7.

The system according to the claimed group of inventions, including three comparison sensors and one control sensor, is installed as follows: the semiconductor sensor S _K is placed in the first hermetically sealed gas chamber with a volume of 100 l, filled with nitrogen. Each of the semiconductor sensors S _cp is placed in a separate hermetically sealed gas chamber with a volume of 100 l, filled with nitrogen. All sensors are connected to the controller by a wired connection and the absence of actuation of the system in this state is recorded. The controller is configured to take into account the content of background gases recorded by each of the comparison sensors, equally. In all gas chambers containing the comparison sensors and the control sensor, 500 ppm of model gas simulating the signal gas are simultaneously dosed. The actuation of the system is recorded by registering a notification issued by the controller, informing about the overheating of the electrical equipment elements. In this example, the system is triggered by the detection by the control sensor and comparison sensors of a model gas simulating the signal gas under conditions of a rapid increase in its concentration.

Example 8.

The system according to the claimed group of inventions, including three comparison sensors and three monitoring sensors, is installed as follows: each of the semiconductor sensors S _K is placed in a separate hermetic gas chamber with a volume of 100 l, filled with nitrogen. Each of the semiconductor sensors Sep is placed in a separate hermetic gas chamber with a volume of 100 l, filled with nitrogen. All sensors are connected to the controller by wire communication and record the absence of actuation of the system in this state. The controller is configured to take into account the content of background gases recorded by each of the comparison sensors, according to formula (1), taking into account the contribution of each comparison sensor separately.

Let us consider one of the control sensors (S _K 1), for which the following formula (2) will be valid:

Sk1 = (ki *Cs _P 1 + k ₂ *Cs _P 2 + kz *Cs _P 3)/3 (2), where C _K 1 is the limiting detectable S _K 1 value of the content of products released during heating of the controlled elements, sufficient for the system to operate, C _c p1-Ccp3 are the values of the content of background gases detected by the comparison sensors S _C pl-S _C p3, respectively, ki-kz are the coefficients of non-uniformity of gas distribution, determined experimentally for each comparison sensor. In this case: ki = 1, kg = 0.5, kz = 0.

In all gas chambers containing comparison sensors, a model gas simulating the background gas is continuously dosed at a rate of 50 ppm/min until its content in each chamber is reached, as shown in Table 1. Then, according to formula (2), С _К 1 = (1*250 + 0.5*1000 + 0* 1500)/3 = 250 ppm.

At the same time, the model gas simulating the signal gas is continuously dosed into the first gas chamber containing S _K 1 at a rate of 50 ppm/min. During the first 5 minutes of dosing, until the model gas content in this gas chamber reaches 300 ppm, the absence of the system response is recorded due to the concentrations of foreign gases measured by the comparison sensors. With further dosing and the model gas content simulating the signal gas in the first gas chamber reaches more than 300 ppm, the system response is recorded by registering the signal issued by the controller, informing about the heating of the electrical equipment elements.

Table 1.

In this example, the system is triggered by the detection by the control sensor of a model gas simulating a signal gas, under conditions of the influence of background gases on the comparison sensors, taking into account the different contribution of each comparison sensor.

Example 9.

An example of the implementation of algorithms for processing concentrations measured by sensors by a controller and generating a notification of overheating in a system according to the claimed group of inventions, including one or more monitoring sensors and one comparison sensor connected to the controller. Initial signal averaging:

вычисляется в результате усреднения за Т секунд (бегущее среднее), по N значениям мгновенного сигнала

To filter out possible instantaneous signal jumps that may be associated with induced electromagnetic interference, it is quickly averaged. The signal used for further analysis

calculated as a result of averaging over T seconds (running average), over N values of the instantaneous signal

Correction of the reference (zero) signal level:

The reference (zero) value of the signal is constantly subject to smooth adjustment, since it changes over time (drifts) due to degradation of the sensitive element, changes in temperature and humidity of the environment, and also due to the possible presence of foreign gases in the atmosphere.

принимается среднее значение измеряемой сенсором абсолютного значения характеристики ^х^ за последние Td минут. В случае, если значение сигнала ^х^ упало ниже нулевого значения, то нулевое значение становится равным

.

As a zero value

the average value of the absolute value of the characteristic ^x ^ measured by the sensor over the last Td minutes is taken. If the value of the signal ^x ^ falls below zero, then the zero value becomes equal to

.

In this case, the relative value of concentration in conventional units will be equal at each moment in time:

Constant response threshold:

A notification about overheating of controlled elements (transition to alarm mode) is generated by default when the concentration threshold is exceeded. ( > р _г

Depending on the sensitivity level setting of the controller, the threshold gas concentration value changes: At low (LF mode) sensitivity ¹ p

At average (midrange mode) sensitivity ² p

At high (HF mode) sensitivity ³

Exit from the alarm mode occurs when the sensor concentration drops below half of the corresponding threshold value.

Floating response threshold:

In this mode, the threshold value P is adjusted depending on the magnitude of fluctuations in foreign gases. When the sensor is turned on,

P = P the threshold value is taken as constant and equal to ² (average

T sensitivity). During ^f days (1 day or more) the maximum value of the signal S ^max is recorded, which does not lead to the formation of an alarm signal (i.e. does not exceed the current threshold value). If this value is less than the current threshold by K times (for example, K = 3), then the threshold is reduced by 1.1 times. If this condition is not met, then the threshold is increased by 1.1 times.

R R

The threshold change can only occur in the range between ¹ and ³ .

R R exceeding the floating threshold value of ^3, it is taken to be equal to ^3. When

When the floating threshold decreases below the value ^1, it is taken to be equal to ¹ .

Algorithm for taking into account the signal measured by the comparison sensor:

The comparison sensor is installed in a place where the probability of an increase in the concentration of signal gas or insulation thermal destruction products will be minimal and serves to detect false alarms.

To take into account the possible delay in the propagation of gas, the concentrations are taken into account

Срабатывание контролирующего сенсора будет трактоваться ложным, если при переходе формировании извещения о нагреве контролируемых элементов будет выполняться условие:

T of the comparison sensor occurs as follows. During the time ^t ' the maximum concentration value measured by the comparison sensor is determined:

The triggering of the control sensor will be interpreted as false if, during the transition to the formation of a notification about the heating of the controlled elements, the following condition is met:

Generating a fire alarm or fire notification:

The activation of internal gas sensors, regardless of the concentrations recorded by the external sensor or adjacent internal sensors, occurs when the following condition is met:

X(f) > P _fm р. where ^,ге is the threshold value of gas concentration, which indicates the possible occurrence of a fire.

Tables 2-4 present possible settings for the controller implementing the considered example of mathematical algorithms.

Table 2. System parameters (settings). Option 1.

Table 3. System parameters (settings). Option 2.

Результаты проведенных испытаний доказывают реализацию заявленного назначения системы и способов по заявленной группе изобретений и достижение технического результата. Группа изобретений была раскрыта выше со ссылкой на конкретный вариант его осуществления. Для специалистов могут быть очевидны и иные варианты осуществления заявленной группы изобретений, не меняющие ее сущности, как она раскрыта в настоящем описании. Соответственно, группу изобретений следует считать не ограниченной по объему приведенными описанием и примерами. Table 4. System parameters (settings). Option 3.

The results of the tests conducted prove the implementation of the declared purpose of the system and methods for the declared group of inventions and the achievement of the technical result. The group of inventions was disclosed above with reference to a specific embodiment of its implementation. Other embodiments of the declared group of inventions that do not change its essence as disclosed in the present description may be obvious to specialists. Accordingly, the group of inventions should be considered not limited in scope by the description and examples provided.

Claims

Formula 1. A system for automatic detection of overheating of electrical equipment elements, including: - gas sensor S _K , designed to detect gases released during heating of the controlled element or thermally activated gas-emitting materials installed on it; - gas sensor S _cp , designed to determine the concentration of background gases in the air near the controlled area; - a controller configured to be connected to at least two gas sensors, including at least one monitoring sensor S _K and at least one comparison sensor S _cp , and to generate a notification of overheating and/or transmit information about such overheating to another device. 2. The system according to claim 1, wherein the sensors are semiconductor type sensors, the sensitive element of which is designed with the possibility of detecting gases released during heating of insulating materials, including, in particular, cross-linked polyethylene (PE), polyvinyl chloride (PVC), rubber, silicone, epoxy resin. 3. The system according to item 1, characterized in that the sensors are designed to detect gases released during heating of thermally activated gas-emitting stickers installed on the controlled elements. 4. The system according to item 1, characterized in that it additionally includes thermally activated gas-emitting materials, preferably multiple-action, included in the composition of products or coatings installed or applied to the controlled elements. 5. The system according to claim 1, characterized in that S _K and S _cp have a sensing element of the same type and are designed to detect gases belonging to classes of compounds selected from the list: halocarbons, hydrogen halides, halogenated hydrocarbons, alkenes, alkanes, mercaptans, acids or mixtures thereof, preferably gases selected from the list: carbon tetrafluoride, tetrafluoroethylene, tetrachloroethylene, trifluorochloromethane, chloroform, dichloromethane, methyl chloride, methyl bromide, trifluoromethane, ethyl chloride, vinyl chloride, hydrogen fluoride, hydrogen chloride, ethylene, propylene, butadiene, isoprene, 65 methane, ethane, butane, hexane, methyl mercaptan, dimethyl sulfide, ethyl mercaptan, diethyl sulfide, nitric acid, nitrous acid or mixtures thereof. 6. The system according to claim 1, characterized in that the controller is configured to generate a notification about overheating of an element of electrical equipment upon detection of S _K gases released during heating of the controlled element or thermally activated gas-emitting materials installed on it, in a concentration higher than a specified limit value, regardless of the current concentration of background gases detected S _cp . 7. The system according to claim 1, characterized in that it contains more than one S _cp and/or S _K , and the formation of a notification by the controller can occur taking into account the average values of the signals recorded by the sensors S _cp and/or S _K , with the same or different contribution from each sensor. 8. The system according to item 1, characterized in that it is intended to detect overheating of contacts and contact connections of closed electrical equipment, including contact connections of electrical panels, complete switchgear units, low-voltage complete switchgear units, and distribution block boxes of windings. 9. The system according to item 1, characterized in that it is designed to detect overheating of insulating materials of electrical equipment elements, including cable joints. 10. The system according to item 1, characterized in that it is intended to prevent fires in electrical equipment. 11. The system according to item 1, characterized in that it additionally has a self-diagnostic function that informs about the need to replace the sensitive element of one or more sensors. 12. The system according to item 1, characterized in that it is additionally equipped with one or more temperature sensors. 13. The system according to claim 1, characterized in that the controller uses one or more of the following algorithms for processing signals received from gas sensors: zero value correction; calculation of the running average value from each sensor for a given period of time; 66 determining the reduced running average value as the difference of two running average values obtained from one sensor over two different time intervals, preferably a short interval of less than one minute and a long interval of more than 5 minutes; comparing the reduced running average value with a threshold value and generating an overheating notification if it is exceeded; determining the average value of a signal received from different sensors by averaging the reduced running average values; comparing the difference of the reduced running average values of signals from a comparison sensor and a monitoring sensor, including those calculated over different time intervals, with a given threshold value; determining the growth rate of the reduced running average value and comparing it with a set threshold value; comparing the signal received from the monitoring sensor with a set threshold value; determining the growth rate of the difference of the reduced running average value of the signal of the monitoring sensor and the comparison sensor and comparing it with a set threshold value; determination or modification of threshold values based on the analysis of signal values received from sensors during operation; adaptive response threshold. 14. The system according to claim 1, characterized in that the controller is configured to generate a notification about overheating of an element of electrical equipment and/or transmit information about such overheating to another device upon detection by at least one S _cp of gases released during heating of the controlled element or thermally activated gas-emitting materials installed on it, in a concentration exceeding threshold values. 15. The system according to item 1, characterized in that the controller is designed with the ability to generate a notification about overheating of an element of electrical equipment and/or transmit information about such overheating to another device when Sk is exposed to gases released during heating of the controlled element or 67 thermally activated gas-emitting materials installed on it, in a concentration exceeding the threshold value, taking into account the content of background gases that affected these sensors during the previous period of time. 16. A method for testing the system according to item 1, including the following actions: installing S _K in the first gas chamber and installing S _cp in the second gas chamber, connecting the controller to the specified sensors; - registration of the fact of the system’s operation in conditions of the absence of the influence of background gases on S _cp by heating the model element in the first chamber and/or determining threshold concentrations by dosing the model gas into the first chamber; - registration of the fact that the system does not operate when dosing model gas into both chambers by filling the first and second chambers with background or model gas and/or determining the threshold concentrations for the system to operate by separately dosing model gas into the first and second chambers. 17. The method according to claim 16, wherein heating the model element includes heating a thermally activated gas-emitting material in a gas chamber with a monitoring sensor. 18. A method for automatically detecting overheating of electrical equipment elements, comprising: placing a system according to claim 1, wherein at least one gas sensor S _K is installed inside the controlled zone; at least one gas sensor S _cp is installed outside the controlled zone; the controller is installed in an arbitrary location and communicates with at least two gas sensors, including at least one S _K and at least one S _cp , by wired or wireless communication; processing a notification of overheating generated by the controller, followed by issuing an information message and/or transmitting data to another device connected to the controller. 19. The method according to item 18, characterized in that it is intended to detect overheating of contacts and contact connections of closed electrical equipment, including 68 contact connections of electrical panels, complete switchgear units, low-voltage complete switchgear units, distribution block boxes of windings. 20. The method according to item 18, characterized in that it is intended to detect overheating of insulating materials of electrical equipment elements, including cable joints. 21. The method according to paragraph 18, characterized in that it is intended to prevent fires in electrical equipment. 22. The method according to paragraph 18, characterized in that it is intended to detect defects in insulating materials of electrical equipment elements that arise as a result of the passage of arc discharges. 23. The method according to claim 18, characterized in that the controller can also generate an overheating notification when one of the sensors detects gases released during heating of the controlled elements or thermally activated gas-emitting materials installed on it, in a concentration higher than a specified limit value, regardless of the content of background gases detected by at least one other sensor. 24. The method according to item 18, characterized in that it is intended to detect overheating using thermally activated gas-emitting materials, primarily of multiple action, included in the composition of products or coatings installed or applied to the monitored elements. 69