CN111584201A - A liquid compensation system for natural ester transformers - Google Patents

Abstract

A liquid compensation system for a natural ester transformer, comprising an oil tank and an oil conservator, the space in the oil conservator provides expansion space for natural ester insulating oil, and the volume V used to fill the natural ester insulating oil in the oil tank and the operating temperature T of the transformer are obtained The lowest value T ₁ and the highest value T ₂ of ; the movement temperature interval of natural ester insulating oil is divided into three intervals, and the expansion coefficients of the three intervals are obtained and substituted into the formula: V ₁ =V*[(t ₁ ‑T ₁ ) *Y ₁ +(t ₂ ‑t ₁ )*Y ₂ +(T ₂ ‑t ₂ )*Y ₃ ], the volume V ₁ of the oil conservator is obtained by calculating, and the piping system connecting the oil conservator and the oil tank is provided with a A fault alarm device that is triggered when natural ester insulating oil is used abnormally. The invention can accurately obtain the expansion space required by the oil storage tank and reduce the cost.

Description

A liquid compensation system for natural ester transformers

technical field

The invention relates to the field of power transformer products, in particular to a liquid compensation system for natural ester transformers.

Background technique

Existing low-voltage products do not have on-site vacuuming process requirements, resulting in relatively low product performance. With the gradual improvement of users' requirements for product performance, the popularization of on-site process requirements such as vacuuming, especially for pressure balance and protection requirements is gradually manifested. The existing technology and related product structure have the following defects when applied to natural ester transformers: first, the design of the oil conservator is relatively simple, and is designed according to the maximum expansion coefficient of the natural ester insulating oil, so that the volume of the oil conservator is relatively large. The large and bulky oil conservator not only causes a waste of space, but also increases the difficulty of the matching installation of the oil conservator and the oil tank due to its large size. At the same time, the larger oil conservator reduces the insulation of the transformer live body. distance, which makes the transformer have potential safety hazards; second, natural ester insulating oil is different from mineral oil. Compared with mineral oil, natural ester insulating oil cannot be in direct contact with air, and it is easy to oxidize and has high viscosity, and the expansion coefficient of natural ester insulating oil It is not a fixed coefficient, and the direct use of the existing mineral oil transformer liquid level compensation and protection system is not conducive to the natural ester insulating oil transformer to solve the pressure balance; third, there is no perfect protection system for protecting the natural ester insulating oil. Once a fault occurs, there is no relevant protection equipment. If it cannot be found in time, it will lead to oxidation and deterioration of natural ester insulating oil, performance degradation, and endanger the normal operation of the transformer in severe cases.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the defects of the prior art, and to provide a liquid compensation system for transformers with less space occupation and suitable for natural ester insulating oil.

To achieve the above object, the present invention has adopted the following technical solutions:

A liquid compensation system for a natural ester transformer, comprising an oil tank and an oil conservator arranged on the upper part of the oil tank, a piping system is arranged between the oil conservator and the oil tank, the natural ester insulating oil in the oil conservator and the natural ester in the oil tank The insulating oil is kept connected through the pipeline system, and the space in the oil conservator provides compensation and expansion space for the natural ester insulating oil;

Obtain the volume V used to fill the natural ester insulating oil in the oil tank and the lowest value T ₁ and the highest value T ₂ of the operating temperature T of the transformer;

The operating temperature t of the natural ester insulating oil filled in the oil tank is between t ₀ -t _N , the temperatures t ₁ , t ₂ are selected, and t ₀ <t ₁ <t ₂ <t _N , the temperatures t ₁ , t _2. Divide the operating temperature interval of natural ester insulating oil into three temperature intervals, namely t ₀ -t ₁ interval, t ₁ -t ₂ interval, and t ₂ -t _N interval, and the lowest value of transformer operating temperature T ₁ falls within t ₀ -t ₁ interval, the highest value T ₂ falls into the t ₂ -t _N interval at the same time, and simultaneously obtain the expansion coefficient of natural ester insulating oil in the t ₀ -t ₁ interval, t ₁ -t ₂ interval, and t ₂ -t _N interval Y ₁ , Y ₂ , Y ₃ , the volume V ₁ of the oil conservator (1) is obtained by calculation according to the formula (I):

V ₁ =V*[(t ₁ -T ₁ )*Y ₁ +(t ₂ -t ₁ )*Y ₂ +(T ₂ -t ₂ )*Y ₃ ] (I).

Further, at different operating temperatures t, the expansion coefficient Y of the natural ester insulating oil filled in the oil tank satisfies the following formula:

Y=0.00075+0.0000065*(t+20) (II);

Among them, the operating temperature t takes the intermediate temperature value in the interval t ₀ -t ₁ , the intermediate temperature value in the interval t ₁ -t ₂ , and the intermediate temperature value in the interval t ₂ -t _N , respectively, and substitute them into formula (II) to calculate the natural ester insulation. Oil expansion coefficient Y ₁ of natural ester insulating oil in the interval t ₀ -t ₁ , expansion coefficient Y ₂ of natural ester insulating oil in the interval t ₁ -t ₂ and expansion coefficient of natural ester insulating oil in the interval t ₂ -t _N Y ₃ .

Further, the t ₁ -t ₂ interval can be divided into 2-6 intervals, and the intermediate temperature value of each interval can be substituted into formula (II) to calculate the expansion coefficient of each interval, and the average value of the sum of the expansion coefficients of all intervals can be obtained. Y', use Y' in place of Y ₂ into formula (I).

Further, a fault alarm device is provided on the pipeline system connecting the oil conservator and the oil tank.

Further, the fault alarm equipment includes a gas relay, and the gas relay is provided with a gas acquisition and analysis module and an alarm module. When the gas acquisition and analysis module detects that the natural ester insulating oil is abnormally decomposed, the alarm module of the gas relay is triggered to issue an alarm. .

Further, the fault alarm device includes a shut-off valve, the shut-off valve is kept open when the pipeline system is in normal use, and when the shut-off valve detects that the oil tank leaks, the shut-off valve is automatically closed.

Further, the pipeline system includes a main pipeline provided with a fault alarm device and a backup pipeline connected in parallel with the main pipeline, the main pipeline is connected between the oil conservator and the oil tank, and both ends of the backup pipeline are respectively connected to the fault alarm. On the main pipeline at both ends of the equipment, the standby pipeline is provided with a closing device, which is opened when the main pipeline is in a closed state, so that the oil conservator and the oil tank are temporarily connected through the standby pipeline.

Further, a capsule protection device is provided in the oil storage tank, and the capsule protection device is used to keep the natural ester insulating oil in the oil storage tank isolated from the air. The capsule protection device includes a sealed capsule and a leakage alarm device. The capsule is filled with gas, and the capsule is floated on the surface of the natural ester insulating oil. When the capsule leaks, the leakage alarm device is triggered to issue an alarm.

Further, the leakage alarm device includes a liquid sensor, an alarm unit and a control cable, the control cable is connected between the alarm unit and the liquid sensor, the liquid sensor extends into the capsule, the alarm unit is arranged outside the oil storage tank, and After the liquid sensor detects the leakage of the capsule, it transmits a leakage signal to the alarm unit, and the alarm unit sends out an alarm.

Further, the leakage alarm device includes a gas sensor, an alarm unit and a control cable arranged in the oil conservator, the gas sensor is connected to the alarm unit through the control cable; the gas sensor is located at the bottom end of the side wall of the oil conservator, so The detection end of the gas sensor floats on the surface of the natural ester insulating oil and is between the capsule and the natural ester insulating oil. After the capsule leaks, when the detection end detects that the gas content in the oil conservator reaches a certain volume, the gas sensor passes through. The alarm unit of the control cable box transmits a leakage signal and an alarm unit issues an alarm.

The liquid compensation system of the natural ester transformer of the present invention provides compensation and expansion space for the natural ester insulating oil in the oil tank through the oil conservator, divides the operating temperature of the natural ester insulating oil into three intervals, and then divides the operating temperature of the natural ester insulating oil into three intervals. The volume of the oil conservator can be calculated from the expansion coefficient of the oil conservator, and the space required by the oil conservator can be accurately calculated, avoiding the design of an oil conservator with more excess space, which is beneficial to reduce the design cost of the oil conservator and simplifies the oil conservator. The volume design process. Compared with the existing oil conservator obtained by rough estimation, the liquid compensation system of the natural ester transformer of the present invention can provide expansion space for the natural ester insulating oil in terms of volume, without generating Occupying too much space due to excess expansion space, it is beneficial to reduce costs and improve the safety of the transformer; the oil conservator is arranged on the upper part of the oil tank and is filled with some natural ester insulating oil in the oil conservator, and This ensures that the natural ester insulating oil always fills the fuel tank; further, a fault alarm device is installed on the pipeline system between the oil conservator and the fuel tank, which is triggered when the natural ester insulating oil is abnormally used.

In addition, the fault alarm equipment includes a gas relay and a shut-off valve. The gas relay will issue an alarm when the natural ester insulating oil is abnormally decomposed, and the shut-off valve will automatically close when the oil tank leaks; The insulating oil keeps the capsule protection device that isolates the air. The capsule protection device can avoid the contact between the natural ester insulating oil and the air and the deterioration of the natural ester insulating oil. At the same time, the capsule in the capsule protection device will trigger the leakage alarm device after leakage, which is conducive to timely Maintenance, to ensure the safe operation of the transformer.

Description of drawings

Fig. 1 is the structural representation of the liquid compensation system of a kind of natural ester transformer of the present invention;

Fig. 2 is the structural representation of the liquid compensation system of a kind of natural ester transformer of the present invention;

Fig. 3 is the structural representation of the liquid compensation system of a kind of natural ester transformer of the present invention;

4 is a schematic structural diagram of a capsule protection device in a liquid compensation system for a natural ester transformer of the present invention;

5 is a schematic structural diagram of a capsule protection device in a liquid compensation system of a natural ester transformer of the present invention.

Detailed ways

The design method of the oil conservator 1 of the transformer will be described in detail below, and the specific embodiments of the liquid compensation system of the natural ester transformer of the present invention will be further described with reference to the embodiments given in FIGS. 1 to 5 . A liquid compensation system for a natural ester transformer of the present invention is not limited to the description of the following embodiments.

A liquid compensation system for a natural ester transformer, comprising an oil tank 2 and an oil conservator 1 arranged on the upper part of the oil tank 2, a pipeline system is arranged between the oil conservator 1 and the oil tank 2, and the natural ester insulating oil in the oil conservator 1 It is kept in communication with the natural ester insulating oil in the oil tank 2 through the pipeline system, and the space in the oil conservator 1 provides compensation and expansion space for the natural ester insulating oil;

Obtain the volume V used to fill the natural ester insulating oil in the oil tank 2 and the lowest value T ₁ and the highest value T ₂ of the transformer operating temperature T;

The operating temperature t of the natural ester insulating oil filled in the oil tank 2 is between t ₀ -t _N , and the temperatures t ₁ , t ₂ are selected, and t ₀ <t ₁ <t ₂ <t _N , the temperatures t ₁ , t 2 t ₂ divides the operating temperature interval of natural ester insulating oil into three temperature intervals, namely t ₀ -t ₁ interval, t ₁ -t ₂ interval, and t ₂ -t _N interval, the lowest value of transformer operating temperature T ₁ falls within In the interval t ₀ -t ₁ , the highest value T ₂ falls into the interval t ₂ -t _N at the same time, and the expansion of natural ester insulating oil in the interval t ₀ -t ₁ , t ₁ -t ₂ and t ₂ -t _N is obtained at the same time The coefficients Y ₁ , Y ₂ , Y ₃ are calculated according to the formula (I) to obtain the volume V ₁ of the oil conservator (1):

V ₁ =V*[(t ₁ -T ₁ )*Y ₁ +(t ₂ -t ₁ )*Y ₂ +(T ₂ -t ₂ )*Y ₃ ] (I).

A liquid compensation system for a natural ester transformer of the present invention provides compensation and expansion space for the natural ester insulating oil in the oil tank 2 through the oil conservator 1, and divides the operating temperature of the natural ester insulating oil into three intervals, and then according to The volume of the oil conservator 1 can be calculated from the expansion coefficient of each interval, which can accurately calculate the space required by the oil conservator 1, avoid designing an oil conservator 1 with more excess space, and help reduce the design cost of the oil conservator 1 , which simplifies the design process of the volume of the oil conservator 1.

Provide an optimal embodiment to obtain the volume V used to fill the natural ester insulating oil in the oil tank 2 and the lowest value T ₁ and the highest value T ₂ of the operating temperature T of the transformer;

The operating temperature t of the natural ester insulating oil filled in the oil tank 2 is between t ₀ -t _N , and the transformer selects temperatures t ₁ and t ₂ , and t ₀ <t ₁ <t ₂ <t _N , the temperature t ₁ , t ₂ divide the operating temperature interval of natural ester insulating oil into three temperature intervals, namely t ₀ -t ₁ interval, t ₁ -t ₂ interval, and t ₂ - t _N interval, the lowest value of transformer operating temperature T ₁ falls Enter the t _0- t ₁ interval, the highest value T ₂ falls into the t _2- t _N interval at the same time, and obtain the natural ester insulating oil in the t ₀ -t ₁ interval, t ₁ -t ₂ interval, and t ₂ -t _N interval at the same time. The expansion coefficients Y ₁ , Y ₂ , Y ₃ are calculated according to formula (I) to obtain the volume V _{1 of the oil conservator 1} :

V ₁ =V*[(t ₁ -T ₁ )*Y ₁ +(t ₂ -t ₁ )*Y ₂ +(T ₂ -t ₂ )*Y ₃ ] (I).

Generally speaking, the lowest operating temperature T1 _of the transformer is -20°C, and the highest operating temperature T2 is ₁₂₀ °C. The natural ester insulating oil takes a soybean-based natural ester insulating oil as an example. The operating temperature t filled in the oil tank 2 It varies between t ₀ -t _N , where the temperature of t ₀ is equal to the lowest operating temperature T ₁ of the transformer, that is, t ₀ =T ₁ =-20°C; the temperature of t _N is equal to the highest operating temperature T ₂ of the transformer , namely t _N =T ₂ =120°C. Preferably, t ₁ =40°C, t ₂ =80°C, at this time, the interval t ₀ -t ₁ , the interval t ₁ -t ₂ , and the interval t ₂ -t _N are -20°C-40°C, 40°C-80°C, respectively, 80℃-120℃.

The expansion coefficients Y ₁ , Y ₂ and Y ₃ of the three stages are obtained, and the expansion coefficient Y can be obtained by multiple measurements or calculated. The expansion coefficient Y in the present invention can be obtained by formula (II),

Y=0.00075+0.0000065*(t+20) (II);

In formula (II), t represents the operating temperature of the natural ester insulating oil. When calculating the expansion coefficient Y1 in the interval t ₀ -t ₁ , the middle value in the interval t ₀ -t ₁ is selected and substituted into formula (II). In the present invention, the middle value of -20°C-40°C is substituted into 10°C to obtain Y1= 0.000945; when calculating the expansion coefficient Y2 in the t ₁ -t ₂ interval, select the middle value of the t ₁ -t ₂ interval and substitute it into formula (II), and substitute the middle value of 40°C-80°C, 60°C, to obtain Y2=0.00114; When calculating the expansion coefficient Y3 in the t ₂ -t _N interval, select the middle value of the t ₂ -t _N interval and substitute it into formula (II) and substitute the middle value of 80°C-120°C to obtain Y3=0.0014; , Y2 and Y3 are substituted into the formula (I) to obtain V1=V*(60*0.000945+40*0.00114+40*0.0014)=0.1583V.

The present invention preferably obtains the expansion coefficients Y ₁ , Y ₂ and Y ₃ in the interval t ₀ -t ₁ , interval t ₁ -t ₂ and interval t ₂ -t _N through multiple measurements, namely -20°C-40°C, 40 The expansion coefficients in the three intervals of ℃-80℃ and 80℃-120℃ are respectively 0.000767, 0.000797 and 0.000825. Substitute Y ₁ , Y ₂ , and Y ₃ into formula (I) to obtain V=0.1111*V. It should be noted that there is a certain range of error between the measured value and the result calculated according to the formula, especially the result calculated after the formula is split, but there is no doubt that the result calculated according to the formula is more accurate. to be precise.

Of course, t ₁ and t ₂ can also be other temperature values, and the three temperature intervals can be three unequal parts. Preferably, the interval t ₁ -t ₂ can be divided into 2-6 intervals, and the intermediate temperature value of each interval can be substituted into Formula (II) calculates and obtains the expansion coefficient of each interval, obtains the average value Y' of the sum of the expansion coefficients of all intervals, and substitutes Y' into formula (I) instead of Y ₂ . Of course, the t ₁ -t ₂ interval can also be divided into more intervals.

As shown in Figures 1-5, a liquid compensation system for a transformer includes an oil tank 2 and an oil conservator 1 designed and obtained based on the above formula. The oil conservator 1 is filled with a part of natural ester insulating oil and makes the oil storage tank 1 The natural ester insulating oil in the tank 1 isolates the air, the oil conservator 1 is arranged on the upper part of the oil tank 2, and a piping system is arranged between the oil conservator 1 and the oil tank 2, and the natural ester insulating oil in the oil conservator 1 is The natural ester insulating oil in the oil tank 2 is kept connected through the pipeline system, and the space in the oil conservator 1 provides the expansion space for the natural ester insulating oil. The above fault alarm device is triggered when the natural ester insulating oil is used abnormally.

Compared with the existing oil conservator 1 obtained by rough estimation, the oil conservator 1 in the present invention can not only provide expansion space for natural ester insulating oil in terms of volume, but will not generate excessive expansion space due to excess expansion space. space, which is conducive to reducing costs and improving the safety of the transformer; the oil conservator 1 is arranged on the upper part of the oil tank 2 and is filled with part of the natural ester insulating oil in the oil conservator 1, so as to ensure the natural ester insulating oil Always fill oil tank 2; a fault alarm device is installed on the piping system between oil conservator 1 and oil tank 2, which is triggered when natural ester insulating oil is used abnormally.

Introduced in detail in conjunction with accompanying drawings 1-5, a liquid compensation system for a transformer includes an oil conservator 1 filled with a part of natural ester insulating oil, and the natural ester insulating oil in the oil conservator 1 isolates the air to avoid air Deterioration caused by contact, preferably a capsule protection device that can isolate the natural ester insulating oil from air is installed in the oil conservator 1; There is a pipeline system, the natural ester insulating oil in the oil conservator 1 and the natural ester insulating oil in the oil tank 2 are kept connected through the pipeline system, and the space in the oil conservator 1 provides the expansion space for the natural ester insulating oil. It is arranged on the upper part of the oil tank 2 and keeps the oil tank 2 connected with the oil conservator 1. Since the oil conservator 1 is always filled with a part of natural ester insulating oil, it can ensure that the natural ester insulating oil in the oil tank 2 is always filled. Therefore, it is only necessary to ensure that the oil conservator 1 is isolated from the air to ensure that the natural ester insulating oil in the oil tank 2 does not come into contact with the air, and a fault alarm device is provided on the pipeline system connecting the oil conservator 1 and the oil tank 2. The fault alarm The equipment will be triggered when the natural ester insulating oil is used abnormally, which is helpful for the staff to find the fault in time.

Preferably, as shown in FIGS. 1-3 , the pipeline system includes a main pipeline 31 provided with a fault alarm device and a backup pipeline 32 connected in parallel with the main pipeline 31 . The main pipeline 31 is connected between the oil conservator 1 and the oil tank 2 , the two ends of the standby pipeline 32 are respectively connected to the main pipeline 31 at both ends of the failsafe system, and the standby pipeline 32 is provided with a closing device, and the closing device is opened when the main pipeline 31 is in a closed state, so that the oil conservator 1 It is temporarily connected with the oil tank 2 through the backup pipeline 32 to ensure that the transformer can run without power during regular inspection and maintenance. During operation, the butterfly valve of the main pipeline 31 is opened to make the main pipeline 31 operate normally, and the ball valve is closed to close the backup pipeline 32; during regular inspection and maintenance, the main pipeline 31 is closed by closing the butterfly valve and opening the ball valve, and the oil tank 2 and the oil storage The cabinets 1 are communicated through backup pipes 32 .

The fault alarm device includes a gas relay 41 and a shut-off valve 42. The gas relay 41 is located on the side close to the oil tank 2, and the shut-off valve 42 is located on the side close to the oil storage tank 1. The gas relay 41 is provided with gas acquisition and analysis. Module and alarm module, when the gas acquisition and analysis module detects abnormal decomposition of natural ester insulating oil, the alarm module of gas relay 41 is triggered to issue an alarm. In years, its molecules will naturally or fail to decompose under high temperature and high voltage in the transformer, and the gas composition of failure decomposition and natural decomposition is different. The gas collection and analysis module of the gas relay 41 can provide this part of the gas collection and quantitative alarm. When When the faulty gas accumulates to a certain amount, the alarm module of the gas relay 41 is triggered to send out an alarm signal, so that the maintenance personnel can judge the fault.

The shut-off valve 42 is kept open when the pipeline system is in normal use, and when the shut-off valve 42 detects that the oil tank 2 leaks, the shut-off valve 42 is automatically closed. At the preset value of the cut-off valve 42, when the flow rate of the natural ester insulating oil in the pipeline system exceeds the preset value of the cut-off valve 42, the pressure difference generated when the natural ester insulating oil flows through will trigger the cut-off valve 42 is automatically closed and an alarm is issued. Usually, the flow rate of the natural ester insulating oil is too fast and the shut-off valve 42 is closed only when leakage occurs, and the flow rate is too fast. Under a fixed value, the shut-off valve 42 is kept open to ensure the normal flow of the natural ester insulating oil due to thermal expansion and contraction. Of course, the shut-off valve 42 is provided with a flow regulating device, and the trigger setting value of the shut-off valve 42 can be adjusted according to the toilet pressure difference or setting convention. The type of the shut-off valve 42 is the type RDR MK II shut-off valve 42 from COMEM.

Preferably, a capsule protection device is provided in the oil storage tank 1, and the capsule protection device is used to keep the natural ester insulating oil in the oil storage tank 1 isolated from the air. The capsule protection device includes a sealed capsule 51 and a leakage alarm device. , the capsule 51 is filled with gas and floated on the surface of the natural ester insulating oil, the capsule 51 is similar to a balloon, the inlet of the capsule 51 is communicated with the outside world, and the capsule 51 is usually filled with air, In this way, the inlet of the capsule 51 can be directly communicated with the air, and the capsule 51 plays a role in balancing the oil conservator 1 with the atmospheric pressure. When the natural ester insulating oil in the transformer expands, the amount of oil in the oil conservator 1 increases. The gas in the capsule 51 is discharged. When the temperature of the transformer decreases, the natural ester insulating oil shrinks, and the amount of oil in the oil conservator 1 decreases. The capsule 51 is affected by the negative pressure and begins to inhale air to expand the capsule 51. Usually, the capsule 51 is filled with dry gas. Preferably, a drying device 54 is provided to keep the gas in the capsule 51 dry. When the capsule 51 leaks, the leakage alarm device is triggered to issue an alarm. The leakage alarm device has two alarming principles.

A first leakage alarm device is provided, as shown in FIG. 4 , the leakage alarm device includes a liquid sensor 52, an alarm unit and a control cable, and the control cable is connected between the alarm unit and the liquid sensor 52, and the liquid sensor 52 Protruding into the capsule 51 , the alarm unit is arranged outside the oil conservator 1 , and an oil level gauge is usually arranged in the oil conservator 1 . When the capsule 51 leaks, some natural ester insulating oil enters the capsule 51 to trigger the liquid sensor 52. At this time, the liquid sensor 52 detects that the capsule 51 leaks, and transmits a leak signal to the alarm unit, and the alarm unit issues an alarm.

A second leakage alarm device is provided, as shown in FIG. 5 , the leakage alarm device includes a gas sensor 53, an alarm unit and a control cable arranged in the oil conservator 1, and the gas sensor 53 is connected with the alarm unit through the control cable The gas sensor 53 is located at the bottom end of the side wall of the oil storage tank 1, and the detection end of the gas sensor 53 floats on the surface of the natural ester insulating oil and is between the capsule 51 and the natural ester insulating oil, and the detection end can follow the natural The liquid level of the ester insulating oil changes. After the capsule 51 leaks, the air flows into the oil conservator 1. When the detection end detects that the gas content in the oil conservator 1 reaches a certain volume, it is usually used to detect the volume of the air. The gas sensor 53 transmits a leakage signal through the control cable box alarm unit and an alarm unit issues an alarm.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be considered that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deductions or substitutions can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (10)

1. a liquid compensation system of natural ester transformer is characterized in that: It comprises an oil tank (2) and an oil conservator (1) arranged on the upper part of the oil tank (2), a pipeline system is arranged between the oil conservator (1) and the oil tank (2), and the natural ester in the oil conservator (1) The insulating oil is kept in communication with the natural ester insulating oil in the oil tank (2) through the pipeline system, and the space in the oil conservator (1) provides compensation and expansion space for the natural ester insulating oil; Obtain the volume V used to fill the natural ester insulating oil in the oil tank (2) and the lowest value T ₁ and the highest value T ₂ of the transformer operating temperature T; The operating temperature t of the natural ester insulating oil filled in the oil tank (2) is between t ₀ -t _N , the temperatures t ₁ and t ₂ are selected, and t ₀ <t ₁ <t ₂ <t _N , the temperature t _{1. t2} divides the operating temperature interval of natural ester insulating oil into three temperature intervals, namely _t0 - _t1 interval, t1- _t2 interval, _{t2 - tN} interval, the lowest value _of transformer operating temperature T1 Falling into the t ₀ -t ₁ interval, the highest value T ₂ falls into the t ₂ -t _N interval at the same time, and simultaneously obtain the natural ester insulating oil in the t ₀ -t ₁ interval, t ₁ -t ₂ interval, and t ₂ -t _N interval The expansion coefficients Y ₁ , Y ₂ , Y ₃ of the oil conservator (1) are calculated according to the formula (I) to obtain the volume V ₁ of the oil conservator (1): V ₁ =V*[(t ₁ -T ₁ )*Y ₁ +(t ₂ -t ₁ )*Y ₂ +(T ₂ -t ₂ )*Y ₃ ] (I). 2. the liquid compensation system of a kind of natural ester transformer according to claim 1, is characterized in that: when different operating temperature t, the expansion coefficient Y that is filled in the natural ester insulating oil in oil tank (2) satisfies following formula : Y=0.00075+0.0000065*(t+20) (II); Among them, the operating temperature t takes the intermediate temperature value in the interval t ₀ -t ₁ , the intermediate temperature value in the interval t ₁ -t ₂ , and the intermediate temperature value in the interval t ₂ -t _N , respectively, and substitute them into formula (II) to calculate the natural ester insulation. Oil expansion coefficient Y ₁ of natural ester insulating oil in the interval t ₀ -t ₁ , expansion coefficient Y ₂ of natural ester insulating oil in the interval t ₁ -t ₂ and expansion coefficient of natural ester insulating oil in the interval t ₂ -t _N Y ₃ . 3. the liquid compensation system of a kind of natural ester transformer according to claim 2, is characterized in that: can divide t ₁ -t ₂ interval into 2-6 interval, the intermediate temperature value of each interval is substituted into formula (II ) Calculate the expansion coefficient of each interval, obtain the average Y′ of the sum of the expansion coefficients of all intervals, and substitute Y′ into formula (I) instead of Y ₂ . 4. The liquid compensation system of a natural ester transformer according to claim 1, characterized in that: a fault alarm device is provided on the pipeline system connecting the oil storage tank (1) and the oil tank (2). 5. the liquid compensation system of a kind of natural ester transformer according to claim 4, is characterized in that: described fault alarm equipment comprises gas relay (41), and described gas relay (41) is provided with gas acquisition analysis module and alarm module, when the gas acquisition and analysis module detects that the natural ester insulating oil is abnormally decomposed, the alarm module of the gas relay (41) is triggered to issue an alarm. 6. the liquid compensating system of a kind of natural ester transformer according to claim 4, is characterized in that: described fault alarm equipment comprises shut-off valve (42), and described shut-off valve (42) is in normal use of pipeline system when Keeping the open state, when the shut-off valve (42) detects the leakage of the fuel tank (2), the shut-off valve (42) is automatically closed. 7. The liquid compensation system of a natural ester transformer according to claim 4, characterized in that: the pipeline system comprises a main pipeline (31) provided with a fault alarm device and a backup pipeline connected in parallel with the main pipeline (31). (32), the main pipeline (31) is connected between the oil conservator (1) and the oil tank (2), and both ends of the backup pipeline (32) are respectively connected to the main pipeline (31) at both ends of the fault alarm device On the upper side, the standby pipeline (32) is provided with a closing device, which is opened when the main pipeline (31) is in a closed state, so that the oil conservator (1) and the oil tank (2) are temporarily connected through the standby pipeline (32). Pass. 8. The liquid compensation system of a natural ester transformer according to claim 4, wherein a capsule protection device is provided in the oil conservator (1), and the capsule protection device is used to make the oil conservator (1). 1) The natural ester insulating oil inside is kept isolated from the air, the capsule protection device includes a sealed capsule (51) and a leakage alarm device, the capsule (51) is filled with gas and the capsule (51) is floated on the natural ester. On the surface of the insulating oil, when the capsule (51) leaks, the leakage alarm device is triggered to give an alarm. 9. The liquid compensation system of a natural ester transformer according to claim 8, wherein the leakage alarm device comprises a liquid sensor (52), an alarm unit and a control cable, and the control cable is connected between the alarm unit and the control cable. Between the liquid sensors (52), the liquid sensor (52) extends into the inside of the capsule (51), and the alarm unit is arranged outside the oil conservator (1). After the liquid sensor (52) detects that the capsule (51) leaks A leak signal is transmitted to the alarm unit and an alarm is issued by the alarm unit. 10. A liquid compensation system for natural ester transformers according to claim 8, wherein the leakage alarm device comprises a gas sensor (53), an alarm unit and a control cable arranged in the oil conservator (1) , the gas sensor (53) is connected to the alarm unit through a control cable; the gas sensor (53) is located at the bottom end of the side wall of the oil storage tank (1), and the detection end of the gas sensor (53) floats on natural ester insulation The oil surface is between the capsule (51) and the natural ester insulating oil. After the capsule (51) leaks, when the detection end detects that the gas content in the oil conservator (1) reaches a certain volume, the gas sensor (53) The leakage signal is transmitted through the control cable box alarm unit and the alarm unit issues an alarm.

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