A method and system for detecting abnormal heating of GIS contacts

Abstract

The present application is a method and system for detecting abnormal heating of GIS contacts, and a GIS busbar temperature monitoring scheme using fiber Bragg grating as a sensor is designed. According to the fiber Bragg grating temperature measurement principle, a fiber Bragg grating temperature sensor with graphene particles added to the organic polymer material of the base is designed, and the hardware and software design of the GIS busbar contact temperature online monitoring system is completed through fiber Bragg grating wavelength data acquisition, sensor parameter setting and wavelength-temperature conversion function, temperature data processing function, fault warning and other functions. The system is used for testing with high temperature measurement accuracy, stable system operation, real-time monitoring of busbar temperature change trend to evaluate the heating state of the busbar, accurately monitor GIS busbar temperature changes, and improve the safety operation level of GIS.

Description

Technical Field

[0001] The present invention relates to the technical field of detecting the working state of electrical equipment, and in particular to a method and system for monitoring the temperature of a cable joint of a cable connected to a gas insulated switchgear (GIS). Background Art

[0002] Theoretically, the failure rate of gas insulated switchgear (GIS) equipment is low, but once a failure occurs, the consequences are more serious than those of ordinary electrical equipment, such as insulation failure, conductor overheating failure, mechanical failure, etc. Among them, thermal failure is one of the most important manifestations of failure. Thermal failure can cause a series of accidents, usually accompanied by flashover, insulation and short circuit accidents. The occurrence of thermal failure means that there is a problem with the reliability of GIS equipment. Therefore, conducting research on the heating of GIS equipment is of great significance to ensure the safe operation of GIS equipment and improve the reliability of power grid operation.

[0003] The cause of the above faults is that the GIS busbar contact has too high a temperature rise due to the increase in contact resistance, which leads to the melting of the busbar contact surface. The metal particles produced by the melting welding cause the electric field to be distorted, which in turn causes an arc. Therefore, if the GIS busbar temperature can be monitored online, the busbar temperature and its development trend can be monitored in real time, and an over-temperature warning can be issued and maintenance can be organized when the busbar is overheated, it will be helpful to reduce the probability of GIS busbar overheating faults, which has practical significance for the safe operation of the power system.

[0004] At present, the main difficulty of online monitoring of GIS bus temperature is that the sensor performance cannot meet the actual needs, which is manifested in the insufficient sensitivity and temperature measurement accuracy of the sensor, and the inability to quickly respond to the temperature changes of GIS bus. Common non-online monitoring methods include infrared temperature measurement methods. Infrared temperature measurement methods measure the temperature information of GIS to determine the corresponding fault location and severity, and have the advantages of non-contact and non-destructive testing. However, infrared thermal imaging temperature measurement is mostly suitable for external and large-area temperature detection, and there is a certain error between the actual results. The correlation between the shell temperature and the conductor temperature is still in the research stage. There is still a lack of effective diagnostic criteria for judging the internal state based on the temperature difference, and it is difficult to realize the integrated integration of the online monitoring system. Distributed optical fiber temperature measurement technology realizes temperature demodulation based on the ratio of the intensity of the anti-Stokes light and the Stokes light excited in the optical fiber. It has the advantages of anti-electromagnetic interference and chemical corrosion resistance. It belongs to the online monitoring method and is also widely used in the power system. However, there are problems such as low temperature measurement accuracy and poor spatial positioning accuracy.

[0005] Fiber Bragg grating temperature measurement technology demodulates the temperature signal according to the change of incident wavelength and reflected wavelength. It has the advantages of strong anti-interference ability, small size, and fixed-point measurement. Its sensitivity and hysteresis characteristics are closely related to the sensor's sensitization and packaging methods. By designing substrates with different structures or materials, the measurement accuracy and sensitivity can be significantly improved to meet actual needs. In this paper, fiber Bragg grating is used as a temperature sensing element to design and develop an online monitoring system for abnormal temperature of GIS busbar contacts. Compared with the temperature measurement results of a single infrared thermal imager, the GIS busbar temperature online monitoring system has high temperature measurement accuracy and sensitivity, can monitor the heating condition of the busbar in real time and effectively, and improves the safe operation level of GIS. Summary of the invention

[0006] In order to solve the technical problems of inaccurate detection results and inability to provide real-time feedback of contact temperature in the prior art, the present invention provides a method and system for detecting abnormal heating of GIS contacts. The technical solution is as follows:

[0007] On the one hand, a GIS contact abnormal heating detection system is provided, comprising a GIS cavity, a fiber grating sensor, a busbar connector, and a disconnector connector, characterized in that:

[0008] Also includes infrared detection sensors;

[0009] The infrared detection sensor is arranged outside the shell of the GIS cavity by inserting into the GIS cavity wall;

[0010] The fiber grating sensors are arranged in three groups, each group is provided with two fiber grating sensors, and a total of six fiber grating sensors are arranged; the three groups of fiber grating sensors include two first groups of fiber grating sensors arranged around the busbar joint, two second groups of fiber grating sensors arranged around the infrared detection sensor, and two third groups of fiber grating sensors arranged around the disconnector joint;

[0011] By comparing the temperature detection result of the infrared detection sensor with the detection results of the fiber grating sensor and the fiber grating sensor, if the results are consistent and both show a high temperature alarm of the busbar joint, a high temperature alarm program is started.

[0012] On the other hand, a method for detecting abnormal heating of GIS contacts is provided, which adopts a GIS contact abnormal heating detection system as described above, and is characterized in that:

[0013] The light is emitted by a broad spectrum light source;

[0014] The light emitted by the broadband light source is filtered by an adjustable filter;

[0015] The light filtered by the adjustable filter enters the optical path switch;

[0016] The three optical fibers led out of the optical path switch are connected via sensing optical cables to correspond to the six fiber grating sensor temperature measurement points and the reference fiber grating sensor respectively;

[0017] After being reflected by the ends of the six fiber grating sensors, the optical fiber returns to the optical path switch through the sensor optical cable and enters the optical detector module, converts the optical signal into an electrical signal and interacts with other modules through the data bus, thereby entering the data processing step.

[0018] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0019] 1. The temperature measurement method combining the outer shell infrared detection sensor and the internal fiber grating sensor is adopted to further improve the accuracy of GIS temperature detection and avoid false alarms of system failures;

[0020] 2. Accurately locate the fever location by setting multiple fever detection points;

[0021] 3. Encapsulate the fiber Bragg grating in an organic polymer substrate with graphene particles to further improve the temperature sensitivity of the fiber Bragg grating sensor and significantly improve the measurement accuracy and sensitivity;

[0022] 4. Through the functions of fiber Bragg grating wavelength data collection, sensor parameter setting and wavelength-temperature conversion, temperature data storage, fault warning, fault data storage, etc., the fault analysis algorithm is used to realize the real-time detection of abnormal heating of GIS contacts. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a schematic diagram of GIS sensor distribution;

[0025] Figure 2 This is a schematic diagram of the GIS contact abnormal heating detection system.

[0026] Among them: 1-GIS cavity, 2-GIS cavity wall, 3-infrared detection sensor, 4-busbar connector, 5-isolating switch connector, 6-1-a group of fiber grating sensors, 6-2-two groups of fiber grating sensors, 6-3-three groups of fiber grating sensors, 2-1 broadband light source, 2-2 tunable filter, 2-3 reference fiber grating, 2-4 optical path switch, 2-5 light detector module, 2-6 infrared detection module, 2-7 spectrum analysis unit, 2-8 calibration unit, 2-9 communication interface, 2-10 bus DETAILED DESCRIPTION

[0027] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0028] In order to better understand the spirit of the present application, it is further described below in conjunction with some preferred embodiments of the present application. In the full text of the present application specification, the same or similar components and components with the same or similar functions are represented by similar figure marks. The embodiments of the accompanying drawings described herein are illustrative and graphical and are used to provide a basic understanding of the present application. The embodiments of the present application should not be interpreted as limiting the present application.

[0029] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0030] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0031] The embodiment of the present invention provides a method and system for detecting abnormal heating of GIS contacts. Figure 1 As shown, the structure setting in the system includes: three groups of 6 fiber grating sensors, one group of fiber grating sensors 6-1, two groups of fiber grating sensors 6-2, three groups of fiber grating sensors 6-3, and infrared detection sensor 3. The cable can be connected to the cable socket through the bus connector 4 to transmit power to the GIS switchgear 1. In use, if the connection between the bus connector 4 and the cable socket is poor, a large contact resistance may occur at the bus connector 4; in this case, when the current flows in the cable, the temperature of the bus connector 4 may increase greatly.

[0032] In order to improve the temperature sensitivity of the fiber Bragg grating, the fiber Bragg grating is encapsulated in an organic polymer substrate, and the driving effect of the substrate is used to increase the temperature sensitivity of the fiber Bragg grating temperature sensor by 12.3 times. In this embodiment, in order to further improve the temperature sensing efficiency, graphene particles are added to the organic polymer material of the substrate to improve the heat transfer effect of the substrate and further improve the temperature sensitivity of the fiber Bragg grating.

[0033] Since abnormal heating of GIS is usually concentrated at the busbar joint 4 and the disconnector joint 5, the fiber grating sensor 6-1 is installed at the busbar joint 4, and the fiber grating sensor 6-3 is installed at the disconnector joint 5; by setting up multiple detection beds at multiple heating points, the heating position can be accurately located. In addition, in order to further improve the accuracy of high-temperature detection of busbar joints, an infrared detection sensor 3 is set at the hot spot position near the busbar joint on the GIS shell; in this embodiment, the infrared detection sensor 3 is set outside the shell of the GIS cavity 1 by inserting into the GIS cavity wall 2; a fiber grating sensor 6-2 is set around the infrared detection sensor 3 and in the shell of the GIS cavity 1. When the fiber grating sensor detects an abnormal temperature alarm, the temperature detection result of the infrared detection sensor 3 is used for comparison to verify the current abnormal high temperature state.

[0034] Specifically, by comparing the temperature detection result of the infrared detection sensor 3 with the detection results of the fiber grating sensor 6-2 and the fiber grating sensor 6-1, if the results are consistent and both show a high temperature alarm, the high temperature alarm program is started; if only the infrared detection sensor 3 and the fiber grating sensor 6-2 have a high temperature alarm, and the fiber grating sensor 6-1 is normal, the error prompt program is started to prompt that the fiber grating sensor 6-1 has a working state error; if only the infrared detection sensor 3 and the fiber grating sensor 6-1 have a high temperature alarm, and the fiber grating sensor 6-2 is normal, the error prompt program is started to prompt that the fiber grating sensor 6-2 has a working state error; if only the fiber grating sensor 6-1 and the fiber grating sensor 6-2 have a high temperature alarm, and the infrared detection sensor 3 is normal, the error prompt program is started to prompt that the infrared detection sensor has a working state error; if only the fiber grating sensor 6-1 or the fiber grating sensor 6-2 has a high temperature alarm or the infrared detection sensor 3 has a high temperature alarm, the error prompt program is started to prompt that the working state error is wrong and the sensor is repaired.

[0035] The design of the fiber Bragg grating direct temperature measurement system refers to Figure 2During the operation of the entire system, the light emitted by the wide-spectrum light source 2-1 is filtered by the adjustable filter 2-2 and then enters the optical path switch 2-4. The three optical fibers led out of the optical path switch 2-4 are connected to the six optical fiber grating temperature measurement points and the reference optical fiber grating 2-3 in the optical fiber grating temperature sensors 6-1, 6-2, and 6-3 respectively through the sensing optical cable. The sensor is placed at the internal joint of the combined electrical appliance to sense its temperature change. The external temperature change causes the central wavelength of the sensor grating to change, and only the pulse light matching the central wavelength of each optical fiber grating can be reflected back. After being reflected at the end of the sensor, it returns to the optical path switch 2-4 again through the sensing optical cable, and then enters the optical detector module 2-5. After converting the optical signal into an electrical signal, it interacts with other modules through the data bus 2-10, and then enters the data processing stage. The data processing stage includes a spectrum analysis unit 2-7 and a calibration unit 2-8. Through the above data processing stage, data communication is carried out with the master control 2-10 through the communication interface 2-9, and data interaction and feedback are carried out.

[0036] Specifically, the data processing stage includes shaping, filtering and other processing by the signal conditioning circuit. The digital signal processing module performs A / D conversion on the processed signal, determines the position of the central wavelength of each reflected light and its corresponding sawtooth scanning voltage value through a certain peak search method, and realizes wavelength demodulation based on the relationship between the FP cavity scanning voltage and the transmission wavelength obtained by fitting. Finally, the temperature value of each fiber grating sensor is calculated and stored based on the calibration relationship between wavelength and temperature.

[0037] In addition, in order to avoid false alarms of system failures, the test data of the infrared detection module 2-6 is incorporated into the bus 2-10, and the signal conditioning circuit performs shaping, filtering and other processing, and the digital signal processing module performs A / D conversion on the processed signal, and transmits the data to the master control for comparison to verify the abnormal high temperature state. At the same time, the reference fiber Bragg grating is set at a non-heat point outside the shell for data reference, which is used to verify the working status of the equipment.

[0038] In the present invention, the working process of the fiber grating sensor to realize real-time detection of abnormal heating of GIS contacts is as follows:

[0039] After the system is initialized, users can set the sampling period, replace sensors, set or adjust sensor parameters according to actual needs, such as abnormal alarms in the corresponding working status; then the fiber grating wavelength acquisition module starts to collect wavelength data; the temperature conversion module converts the wavelength into temperature; after obtaining the temperature data, the platform will use the fault analysis algorithm to conduct a comprehensive analysis of the measuring point temperature, ambient temperature, and historical measured temperature, draw a temperature change process curve, determine whether the GIS has a fault, and give the fault type.

[0040] Specifically, the fault analysis algorithm process is as follows:

[0041] a: Collecting Raman scattered light through the sensing optical fiber, analyzing the Raman scattered light, obtaining the real-time temperature of each temperature measurement point and the positioning information corresponding to the real-time temperature, and the positioning information is used to determine the location of the abnormal heating;

[0042] b: Determine whether the real-time temperature of each temperature measurement point is normal;

[0043] c: When the real-time temperature is abnormal, retrieve the reference fiber grating temperature measurement value and the infrared detection sensor temperature measurement value;

[0044] d: Compare the abnormal temperature with the reference fiber grating temperature measurement value and the infrared detection sensor temperature measurement value. If the trends are consistent, push the real-time temperature and location information of the abnormal temperature measurement point; if the trends are inconsistent, start the error prompt program.

[0045] Among them, judging whether the temperature is normal includes judging whether the temperature value, the real-time temperature difference and the real-time temperature rise rate are normal in turn. When the temperature value, the real-time temperature difference and the real-time temperature rise rate are all normal, it is judged that the real-time temperature of the temperature measuring point is normal, specifically including:

[0046] S1. Compare the temperature value with the preset maximum temperature. When the temperature value is less than the maximum temperature, the temperature value is determined to be normal; when the temperature value is greater than or equal to the maximum temperature, the temperature value is determined to be abnormal, and steps c and d are executed;

[0047] S2. Compare the real-time temperature difference with the preset safety temperature difference. When the real-time temperature difference is less than the safety temperature difference, the real-time temperature difference is determined to be normal; when the real-time temperature difference is greater than or equal to the safety temperature difference, the real-time temperature difference is determined to be abnormal, and steps c and d are executed;

[0048] S3. Calculate the real-time temperature rise rate of each temperature measuring point according to the change in the temperature value of each temperature measuring point and the corresponding temperature change time, and compare the real-time temperature rise rate with the preset safe temperature rise rate. When the real-time temperature rise rate is less than the safe temperature rise rate, it is determined that the real-time temperature rise rate is normal, and the real-time temperature is determined to be normal; when the real-time temperature rise rate is greater than or equal to the safe temperature rise rate, it is determined that the real-time temperature rise rate is abnormal, and execute steps c and d.

[0049] In summary, the present application realizes the real-time detection of abnormal heating of GIS contacts through fiber Bragg grating wavelength data collection, sensor parameter setting and wavelength-temperature conversion function, fault warning and other functions.

[0050] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A GIS contact abnormal heating detection system, comprising a GIS cavity (1), a fiber grating sensor, a busbar connector (4), and a disconnector connector (5), characterized in that: Also includes an infrared detection sensor (3); The infrared detection sensor (3) is arranged outside the shell of the GIS cavity (1) by inserting into the GIS cavity wall (2); The fiber grating sensors are arranged in three groups, each group is provided with two fiber grating sensors, and a total of six fiber grating sensors are arranged; the three groups of fiber grating sensors include two first groups of fiber grating sensors (6-1) arranged around the busbar joint (4), two second groups of fiber grating sensors (6-2) arranged around the infrared detection sensor (3), and two third groups of fiber grating sensors (6-3) arranged around the disconnector joint (5); By comparing the temperature detection result of the infrared detection sensor (3) with the detection results of the second group of fiber optic Bragg grating sensors (6-2) and the first group of fiber optic Bragg grating sensors (6-1), if the results are consistent and both show a high temperature alarm of the busbar connector (4), a high temperature alarm program is started.

2. The GIS contact abnormal heating detection system according to claim 1 is characterized in that: The system further comprises a reference fiber grating sensor arranged outside the GIS cavity (1).

3. The GIS contact abnormal heating detection system according to claim 2 is characterized in that: The reference fiber Bragg grating is arranged at a non-heating point position outside the shell of the GIS cavity (1) for data reference and for verifying the working status of the equipment.

4. The GIS contact abnormal heating detection system according to claim 1 is characterized in that: The fiber grating sensor adopts an organic polymer substrate.

5. The GIS contact abnormal heating detection system according to claim 4 is characterized in that: The fiber grating sensor adopts an organic polymer substrate in which graphene particles are added to the organic polymer material.

6. A method for detecting abnormal heating of GIS contacts, using a system for detecting abnormal heating of GIS contacts as claimed in any one of claims 1 to 5, characterized in that: The broad spectrum light source (2-1) emits light; The light emitted by the wide-spectrum light source (2-1) is filtered by an adjustable filter (2-2); The light filtered by the adjustable filter (2-2) enters the optical path switch (2-4); The three optical fibers led out of the optical path switch (2-4) are connected via optical cables to correspond to the six fiber grating sensor temperature measurement points respectively, and the reference fiber grating sensor (2-3) is connected to the optical path switch via another optical fiber; After being reflected by the ends of the six fiber grating sensors, the optical fiber returns to the optical path switch (2-4) through the optical cable again and then enters the optical detector module (2-5), converts the optical signal into an electrical signal and interacts with other modules through the data bus (2-10), thereby entering the data processing step.

7. The GIS contact abnormal heating detection method according to claim 6 is characterized in that: The data processing step includes using a spectrum analysis unit (2-7), a calibration unit (2-8), and a communication interface (2-9) to perform data processing. Through the above data processing, data communication is performed with a bus (2-10) via the communication interface (2-9) to perform data interaction and feedback.

8. The GIS contact abnormal heating detection method according to claim 6 is characterized in that: It further comprises an infrared detection module (2-6), the test data of the infrared detection module (2-6) is incorporated into the bus (2-10), the signal conditioning circuit performs shaping and filtering processing, the digital signal processing module performs A / D conversion on the processed signal, and the data is transmitted to the master control for comparison to realize the verification of the abnormal high temperature state; After being reflected at the end of the reference fiber grating sensor (2-3), the light returns to the optical path switch (2-4) through the optical cable and then enters the optical detector module (2-5). After the light signal is converted into an electrical signal, it interacts with other modules through the bus (2-10) and then enters the data processing stage, where it is compared with the data of the six fiber grating sensors for verifying the working status of the equipment.

9. The GIS contact abnormal heating detection method according to claim 6, characterized in that: The working process of the fiber grating sensor to realize real-time detection of abnormal heating of GIS contacts is as follows: After the system is initialized, the user can set the sampling period, replace the sensor, and set or adjust the sensor parameters according to actual needs; then the fiber grating wavelength acquisition module starts to collect wavelength data; The temperature conversion module converts wavelength into temperature; after obtaining the temperature data, the platform will use the fault analysis algorithm to comprehensively analyze the temperature of the measuring point, the ambient temperature, and the historical measured temperature, draw a temperature change process curve, determine whether the GIS has a fault, and give the fault type.

10. The GIS contact abnormal heating detection method according to claim 9, characterized in that: The fault analysis algorithm process is as follows: a: Collecting Raman scattered light through the sensing optical fiber, analyzing the Raman scattered light, obtaining the real-time temperature of each temperature measurement point and the positioning information corresponding to the real-time temperature, and the positioning information is used to determine the location of the abnormal heating; b: Determine whether the real-time temperature of each temperature measurement point is normal; c: When the real-time temperature is abnormal, the reference fiber grating sensor temperature measurement value and the infrared detection sensor temperature measurement value are retrieved; d: Compare the abnormal temperature with the reference fiber grating sensor temperature measurement value and the infrared detection sensor temperature measurement value. If the trends are consistent, push the real-time temperature and location information of the abnormal temperature measurement point; If the trends are inconsistent, the error prompt program is started.

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