WO2017115163A1

WO2017115163A1 - A method and an apparatus for communicating a condition of a power line

Info

Publication number: WO2017115163A1
Application number: PCT/IB2016/056370
Authority: WO
Inventors: Simi VALSAN; Hariram SATHEESH; Anitha Varghese; Mallikarjun Kande
Original assignee: ABB Schweiz AG
Current assignee: ABB Schweiz AG
Priority date: 2015-12-31
Filing date: 2016-10-24
Publication date: 2017-07-06
Anticipated expiration: 2018-06-30

Abstract

The present invention relates to a method and apparatus for communicating a condition of a power line. A method for communicating a condition of a power line in a power transmission system with a first sensor unit from a plurality of sensor units mounted on the power line is disclosed. The method comprises obtaining, by a first sensor unit, measured data of an electrical parameter in the power line. A condition of the power line is determined by processing the obtained measured data by the first sensor unit. The determined condition of the power line is transmitted by determining a first time period based on an electrical signal detected by the first sensor unit to ensure time synchronization. Transmitting the condition of the power line at the determined first time period by the first sensor unit.

Description

A METHOD AND AN APPARATUS FOR COMMUNICATING A CONDITION OF A

POWER LINE

FIELD OF THE INVENTION

[001] The present invention relates generally to fault detection in power lines and more particularly to the communication of a presence or absence of a fault detected in a power line.

BACKGROUND OF THE INVENTION

[002] Power transmission lines could be prone to faults due to various environmental conditions resulting in failure to provide uninterrupted power to customers. Fault indicators of power lines consist of sensing units for sensing, fault detecting and indicating logic. There can be various types of fault occurring in a power line that leads to interrupts in power transmission, the faults could be open circuit or short circuit or ground fault.

[003] Fault indicators may provide local or remote indications. Local indication is achieved by typical Light Emitting Diode (LED) flag indicators, or using some mechanical flag indicators which are standalone local fault indicators. The flag indicators being mounted on the power transmission lines itself require manual inspection of the overhead lines to locate the fault. Automatic fault section identification and notification may not be possible with local indication. It can be a time consuming and man power intensive activity to inspect the fault indications manually.

[004] This drawback of manual inspection of fault can be mitigated using remote fault indicators. For remote fault indication, a sensor unit (fault indicator) sends measured or/and processed data related to a fault wirelessly to a ground unit installed near the sensor unit. The ground unit computes the measured or/and processed data related to the fault to determine a status of the fault and transmits the status of the fault to a central control unit or control center using a communication unit comprised in the ground unit or connected with the ground unit. This overall infrastructure or topology for remote fault indictors need large number of ground units and communication units resulting in an expensive and complex system deployment. [005] Remote fault indicators, are usually of self-supplied nature with an in-built mechanism for energy harvesting from power lines. The energy harvesting mechanism used in the remote fault indicators has a practical limit on the amount of energy that can be harvested. Hence the remote fault indicators are required to process and send the data related to fault within the limit of the harvested energy. Additionally, in existing remote fault indicators long range communication is used as a central node or sensor unit collects measured data from other neighboring sensor units and transmits the measured data to a control centre using long range communication. The usage of long range communication results in high power requirements. Further, there is a high bandwidth requirement for relaying measured data. Hence there is a need to effectively process the fault condition and communicate the fault condition using the available power while achieving a simpler system deployment.

SUMMARY

[006] The above-mentioned shortcomings, disadvantages and problems are addressed herein which will be understood by reading and understanding the following specification.

[007] In one aspect, the present invention provides a method for communicating a condition of one or more power lines in a power transmission system with a first sensor unit from a plurality of sensor units mounted on one or more power lines. The method comprising: obtaining, by a first sensor unit from the plurality of sensor unit, one or more measured data of at least one electrical parameter in the one or more power line; determining, by the first sensor unit, a condition of the one or more power line by processing the obtained one or more measured data; determining, by the first sensor unit, a first time period for time synchronizing the transmission of the condition of one or more power lines based on an electrical signal detected by the first sensor unit, and transmitting, by the first sensor unit, the condition of one or more power lines at the determined first time period.

[008] In another aspect the present invention discloses a sensor unit for communicating a condition of one or more power lines in a power transmission system, the sensor unit comprising, a sensor for detecting at least one electrical parameter and generate one or more measured data of the detected at least one electrical parameter in the one or more power lines; an analyzer to determine a condition of the one or more power lines based on the generated one or more measured data; a communication module for communicating the generated one or more measured data and the condition of the one or more power lines. And a synchronizing module for time synchronizing: the communication of the one or more measured data of the at least one electrical parameter; and the communication of the condition of the one or more power lines.

BRIEF DESCRIPTION OF DRAWINGS

[009] Figure 1 illustrates a power transmission system with a plurality of sensor units mounted on power lines.

[0010] Figure 2 illustrates a sensor unit for communicating a condition of one or more power lines in a power transmission system.

[0011] Figure 3 illustrates a method for communicating a condition of one or more power lines in the power transmission system.

[0012] Figure 4 illustrates a plurality of sensor units wherein a first antenna pattern is enabled in the power transmission system.

[0013] Figure 5 illustrates a plurality of sensor units wherein a second antenna pattern is enabled in the power transmission system.

[0014] Figure 6 illustrates a sensor unit with two dipole antennae aligned perpendicular to each other.

[0015] Figure 7 illustrates a communication of a condition of one or more power lines between two sensor units mounted on different power lines. DETAILED DESCRIPTION

[0016] The present invention is related to a method and apparatus for communicating a condition of one or more power lines in a power transmission system. The condition of a power line is detected and communicated by sensor units mounted on the power line to indicate presence or absence of a fault. A sensor unit that detects the condition of a power line, communicates the condition to an adjacently located sensor unit, and so on, until eventually the condition of the power lines is received by a control centre. There is no ground unit used as one sensor unit relays data to the next sensor unit.

[0017] The sensor unit comprises sensors for sensing measured values of current and voltage in the power line and analyzes the measured values to determine a condition of the power line for presence or absence of fault. Further the condition of the power line is transmitted using antennae to an adjacently located sensor unit. Hence the bandwidth requirement for communication is reduced since the sensor unit only communicates the condition of the power line. The sensor units can be located at a distance where a short range and a medium range communication can be employed. The sensor unit employs energy harvesting techniques to harvest energy from the power line itself on which the sensor unit is mounted. Thus the sensor unit is required to perform its functions (measurement, data processing and communication) within the limits of the harvested energy. The wireless communication in the system may be configured to operate using ZigBee protocol or any 15.4g based technology. The wireless communication in the system may be configured to operate using ZigBee protocol or any 15.4g based technology.

[0018] When a fault occurs in a section of the power line, assuming that a fault protection logic is configured in the sensor unit close to the fault section of the power line, this fault will be detected by the sensor unit. The detected fault data will be transmitted from the sensor unit to the next located sensor unit, for example in the form of a bitstream. The succeeding sensor units will hence keep on forwarding the bitstream while appending its own fault data where each bit is associated with a status of fault until it reaches the control centre. It may be known to the person skilled in the art that different types of fault logic may be configured in the sensor units. [0019] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments, which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is to be understood that other embodiments may be utilized. The following detailed description is, therefore, not to be taken in a limiting sense.

[0020] Figure 1 illustrates a power transmission system 100 with a plurality of sensor units mounted on power lines (112,118 and 120). As shown in Figure 1, the system 100 comprises multiple poles to support the power lines for facilitating transmission of power, wherein each pole is separated by a definite distance. As illustrated in Figure 1, a first sensor unit 110 from the plurality of sensor units is mounted on a first power line 112. Similarly, for example, as shown in Figure 1, a second sensor unit 114 and a third sensor unit 116 are mounted on a second power line 118 and third power line 120 respectively. For this exemplary embodiment, the three sensor units 110, 114 and 116 are located at close proximity to each other and mounted on three separate power lines 112, 118 and 120. A cluster unit 122 comprising the three sensor units 110, 114 and 116 is indicated for ease of explanation. The cluster unit 122 can be repeated at regular intervals in the power transmission system 100 and the condition of the power lines is detected by the sensor units for a section of the power line in between two adjacently located units. For example, the condition of the power lines is communicated from one cluster unit 122 to a next adjacent cluster unit 124 using a medium range communication, until the condition of the power line reaches a control centre, as shown in Figure 1. The communication within the cluster unit can be a short range communication.

[0021] Figure 2 illustrates functional elements of a sensor unit 200 from the plurality of sensor units in the power transmission system. The sensor unit comprises a sensor 210, an analyzer 220, a communication module 230 and a synchronizing module 240. As shown in the Figure 2, the sensor is coupled to the power line 112 for detecting at least one electrical parameter (voltage, current) of the power line 112. The sensor 210 detects an electrical parameter, for example voltage or current in the power line 112 and generates measured data of the detected electrical parameter as per the sampling rate used in the sensor unit. The measured data are processed to determine a condition of the power line 112. The analyzer 220 determines the condition of the power line 112 based on the generated measured data by processing the measured data.

[0022] The generated measured data and the condition of the power line 112 is required to be communicated from one sensor unit of the cluster unit 122 to another sensor unit of the cluster unit 124. The communication module 230 performs the communication operation of the sensor unit. The communication module 230 comprises an antenna module 250 and an antenna scheduling module 260. In an exemplary embodiment, the antenna module 250 can comprise of two dipole antennae aligned perpendicular to each other for generating antenna patterns for communication to sensor units within the cluster and outside of the cluster. The sensor unit 200 can also comprise an energy harvesting module 270 for harvesting power from the power line 112 on which the sensor unit is mounted as shown in Figure 2. The measured data can be communicated using an omni-directional antenna pattern, as the communication takes place within the cluster unit 122. And for communicating the condition of the power line the communication occurs between two cluster units 122 and 124 wherein the distance between the two cluster units is larger in comparison to the distance between sensor units located within a cluster unit. Hence higher power is required for communicating the condition of the power line from cluster unit 122 to the next cluster unit 124 and so a directional antenna pattern can be used for communicating between two cluster units while utilizing the power within the limits of the available power harvested by the energy harvesting module 270. Further, the antenna patterns as required can be generated only during the time of communication of the data.

[0023] Each sensor unit functions independently, therefore activities amongst them needs to synchronized, for example when transmission occurs from one sensor unit to a next sensor unit, the next sensor unit should be ready for reception. Thus two sensor units are required to be in synchronization with each other which is being implemented using the Synchronization module 240. For the purpose of time synchronization, the sensor unit 200 comprises a zero-crossing detector 280 to identify zero crossing of the electrical signal being detected by the electrical parameter (voltage/current) sensor. The time synchronization is brought about by detecting a zero crossing of an electrical signal in the power line detected by the sensor unit and having the functional activities (e.g. communication) performed at a time/phase based on the zero crossing detection. The zero-crossing detector 280 can comprise Phase Locked Loop (PLL) circuitry to implement phase based operation of functional activities.

[0024] Figure 3 is an illustration of the method 300 for communicating a condition of the power line in the power transmission system. As depicted in step 310, using a communication module 230, the first sensor unit obtains measured data of an electrical parameter of the power line. The measured data can be obtained by the first sensor unit 110 from a second sensor unit 114. For example, the measured data can be a value for voltage and a value for current. Additionally, the first sensor unit 110 can obtain measured data of the power line on which the first sensor unit 110 is mounted. The communication module 230 comprises an antenna module 250 comprising one or more antenna and an antenna scheduling module 260 for scheduling a first antenna pattern and a second antenna pattern. A first antenna pattern is enabled when the first sensor unit 110 obtains one or more measured data and a second antenna pattern is enabled when the first sensor unit 110 transmits the condition of the one or more power lines.

[0025] For example, since the first and second sensors are proximately located, an omnidirectional antenna pattern 410 as shown in Figure 4 can be generated while transmitting and receiving the measured data. The first antenna pattern is enabled only for the duration of transmission and reception of the measured data. The generated antenna pattern are auto- configured initially to establish communication.

[0026] In an embodiment, the transmission and reception of measured data takes place by transmitting sampled measured data at 12 samples per cycle or 600 Hz, that is, time between two sampling instants is 1666μ8. Within a cluster, initially a command is issued by the first sensor unit 110 to the other sensor units in the cluster for reset of their timers following which an acknowledgement is received by the first sensor unit. After that the first sensor unit 110 broadcasts to the other sensor units in the cluster requesting for measured data of current and voltage, following which the measured data from the other sensor units in the cluster is received by the first sensor unit 110 in a sequential manner. [0027] As depicted in step 320, using an analyzer 220, the first sensor unit 110 determines a condition of the one or more power lines by processing the obtained sampled pulses of measured data. The condition of the power lines could be an information related to a presence or absence of fault in a particular section of the power line. For example the analyzer 220 can be configured with an over current protection logic for determining a condition of over current when obtained current value data exceeds a pre-determined threshold. The condition of the powerline can be represented in a specific format, for example it may be represented as a bitstream.

[0028] As depicted in step 330, the first sensor unit 110, using a synchronizing module 240, determines a first time period for time synchronizing the transmission of the condition of the power line based on the electrical signal detected by the first sensor unit 110. The time synchronizing of the transmission of the condition is based on a zero crossing detection using a zero-crossing detector 280 of the electrical signal detected by the first sensor unit 110.

[0029] As depicted in step 340, the first sensor unit, using the communication module 230, transmits the condition of the power line. The second antenna pattern is enabled by the antenna scheduling module 260 for communicating the condition of the power line. The communication of the condition occurs from one cluster unit 122 to another adjacently located cluster unit 124 or to a ground unit (not shown) or to the control centre. For example, as shown in Figure 5, a directional antenna pattern 510 for a sensor unit can be deployed while communicating the condition of the power line from one cluster unit to a next cluster unit. Similarly, other sensor units also deploy a directional antenna pattern (510a, 510b).

[0030] Figure 6 illustrates an exemplary sensor unit 600 mounted on a power line 610 with two dipole antennae 620 and 630 aligned perpendicular to each other. The sensor unit 600 is equipped two dipole antennae 620 and 630 aligned perpendicular to each other as shown in Figure 6. An antenna pattern is generated by adjusting phase and magnitude of signal transmitted by dipoles of the two dipole antennae. As it may be appreciated by a person skilled in the art, the antenna pattern can be changed by dynamically adjusting phase and magnitude of the signal transmitted by the dipoles of the two dipole antennae. Further, the antennae is configured to operate only at the time duration during which communication takes place in the sensor unit. On all other instances when a communication is not taking place, the antennae are turned off thus resulting in optimized usage of power. It may be noted by a person skilled in the art that, the above example illustrates a configuration with two dipole antennae, however multiple antenna configurations can be possible to achieve the same results.

[0031] Figure 7 illustrates a communication of a condition of the power line between two sensor units mounted on different power lines. In this embodiment, as shown in Figure 7, a directional antenna pattern 710 is generated for the transmission of the condition of a power line takes place from a sensor unit of a cluster unit in a first power line to a sensor unit of an adjacent cluster unit in a second power line. While transmitting the condition of the power line by a sensor unit of one cluster unit to a sensor unit of an adjacent cluster unit, the sensor units are configured such that when the sensor unit of one cluster unit is in a mode for transmitting the condition of the power line, the sensor unit of the adjacent cluster unit is in a mode for receiving the condition of the power line and vice versa.

[0032] This written description uses examples to describe the subject matter herein, including the best mode, and also to enable any person skilled in the art to make and use the subject matter. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

1. A method (300) for communicating a condition of one or more power lines (112, 118, 120) in a power transmission system (100) with a first sensor unit (110) from a plurality of sensor units mounted on one or more power lines (112,118,120), the method comprising: obtaining (310), by a first sensor unit (110) from the plurality of sensor units, one or more measured data of at least one electrical parameter in the one or more power line (112, 118, 120);

determining (320), by the first sensor unit (110), a condition of the one or more power line (112, 118, 120) by processing the obtained one or more measured data;

determining (330), by the first sensor unit (110), a first time period for time synchronizing the transmission of the condition of one or more power lines (112, 118, 120) based on an electrical signal detected by the first sensor unit (110), and

transmitting (340), by the first sensor unit (110), the condition of one or more power lines (112, 118, 120) at the determined first time period.

2. The method as claimed in claim 1 , wherein the step of obtaining, by a first sensor unit from the plurality of sensor units, one or more measured data of at least one electrical parameter from a second sensor unit at a second time period wherein the second time period is determined and time synchronized based on the electrical signal detected by the first sensor unit.

3. The method as claimed in claim 1, further comprises receiving by a first sensor unit, a condition of one or more power line from a sensor unit from the plurality of sensor units at a third time period wherein the third time period is determined and time synchronized based on the electrical signal detected by the first sensor unit.

4. The method as claimed in claim 1, wherein time synchronizing the transmission of the condition of one or more power lines based on a zero crossing detection of the electrical signal detected by the first sensor unit.

5. The method as claimed in claim 2, further comprises time synchronizing the second time period based on a zero crossing detection of the electrical signal detected by the first sensor unit.

6. The method as claimed in claim 3, further comprises time synchronizing the third time period based on a zero crossing detection of the electrical signal detected by the first sensor unit.

7. The method as claimed in claim 1, wherein a first antenna pattern is enabled when the first sensor unit obtains one or more measured data of at least one electrical parameter and a second antenna pattern is enabled when the first sensor unit transmits the condition of the one or more power lines

8. The method as claimed in claim 1, further comprises transmitting the condition of the one or more power line to at least one of a control centre or a sensor unit or a ground unit.

9. A sensor unit (200) for communicating a condition of one or more power lines (112, 118, 120) in a power transmission system (100), the sensor unit (200) comprising:

a sensor (210) to detect at least one electrical parameter and generate one or more measured data of the detected at least one electrical parameter in the one or more power lines (112, 118, 120);

an analyzer (220) to determine a condition of the one or more power lines (112, 118, 120) based on the generated one or more measured data;

a communication module (230) for communicating the generated one or more measured data and the condition of the one or more power lines (112, 118, 120). and

a synchronizing module (240) for time synchronizing:

the communication of the one or more measured data of the at least one electrical parameter; and

the communication of the condition of the one or more power lines (112, 118, 120).

10. The sensor unit as claimed in claim 9, wherein the communication module comprises an antenna module with one or more antenna and an antenna scheduling module for scheduling a first antenna pattern and a second antenna pattern.