GIS partial discharge positioning method and device with low sampling rate

Abstract

The invention relates to the technical field of equipment state monitoring, in particular to a low-sampling-rate GIS partial discharge positioning method and device. The device comprises a main control circuit, a sampling module and at least two UHF sensors. The method comprises the following steps: acquiring discharge signals acquired by each signal detection terminal and arrival time of the discharge signals, determining two UHF sensors which detect the discharge signals first, and recording the two UHF sensors as first detection terminals; determining the maximum propagation time length between the two first detection terminals; judging whether the time for the discharge signal to reach the two first detection terminals is less than or equal to the maximum propagation time length and whether there is only one partial discharge pulse in the discharge signal; if yes, continuously collecting partial discharge signals detected by the two first detection terminals; and determining the discharge position according to the time difference of the partial discharge signals acquired by the two first detection terminals each time. Through a screening mechanism of the discharge signals, accurate positioning of partial discharge in the GIS equipment is realized.

Description

Technical Field

[0001] The present application relates to the technical field of equipment status monitoring, and more specifically, to a method and device for locating local discharge of a GIS with a low sampling rate. Background Art

[0002] Gas Insulated Switchgear (GIS) has been widely used in substations in modern power systems due to its advantages such as small footprint, high operational reliability, and low susceptibility to environmental factors. However, during the production, manufacturing, transportation, installation and maintenance of GIS, due to product quality problems, human factors or natural aging, the equipment may have potential defects and cause partial discharge. Partial discharge will not only accelerate the deterioration of the insulation material of the equipment, but may also cause insulation breakdown at some point, resulting in unplanned power outages and significant losses to the economy and society.

[0003] Particularly, partial discharges that occur inside pot-type insulators degrade faster because solid insulating materials do not have the ability to self-repair. In order to prevent such failures, it is necessary to detect and locate partial discharges in GIS in a timely manner so as to arrange a reasonable maintenance plan. Currently, the commonly used partial discharge detection methods mainly include online monitoring using ultra-high frequency sensors (UHF) and live detection using ultrasonic technology.

[0004] Once a partial discharge is detected, determining its exact location is crucial for subsequent maintenance. Although existing positioning technologies such as time difference positioning and acoustic and electrical combined positioning can meet the needs to a certain extent, they still face many challenges in practical applications.

[0005] The patent with publication number CN207074246U discloses a GIS partial discharge online monitoring system. The method proposes to use the partial discharge signals captured by multiple groups of UHF sensors and combine them with signal processing algorithms to improve positioning accuracy. However, for ultra-high voltage GIS equipment that has installed a large number of UHF online monitoring devices, it is still difficult to achieve accurate partial discharge positioning due to the sampling rate of the sampling device. The propagation speed of electromagnetic waves inside the GIS is close to the speed of light (about 300 meters / microsecond). In order to achieve a positioning accuracy of decimeters or even centimeters, a sampling rate of GHz is theoretically required, which will significantly increase the cost of the equipment.

[0006] The invention patent with publication number CN115902552A discloses a GIS partial discharge positioning method and device based on multi-terminal data fusion. By optimizing the sensor layout and data fusion algorithm, a high positioning accuracy can be maintained even under low sampling rate conditions. However, the effectiveness of the data fusion algorithm depends on the time synchronization accuracy between sensors. If there is a deviation in time synchronization, the accuracy of the positioning result will be affected.

[0007] Therefore, how to develop a method or system that can achieve high positioning accuracy under low sampling rate conditions is of great significance to ensure the safe operation of GIS equipment. Summary of the invention

[0008] In view of this, the present application provides a low sampling rate GIS partial discharge location method and device to solve the above problems.

[0009] In a first aspect, the present application provides a low sampling rate GIS partial discharge location method, wherein at least two signal detection terminals are provided on the GIS body, and the method comprises:

[0010] When local discharge occurs in the GIS body, the discharge signals collected by each signal detection terminal and the arrival time of the discharge signals are obtained; according to the arrival time of the discharge signals, the two UHF sensors that first detect the discharge signals are determined, both of which are recorded as the first detection terminals; the maximum propagation time length between the two first detection terminals is determined, which is determined by the pulse signal propagation time between the two first detection terminals or the distance between the two first detection terminals; it is determined whether the time when the discharge signal arrives at the two first detection terminals is less than or equal to the maximum propagation time length; if it is less than or equal to, it is determined whether there is and only one local discharge pulse in the discharge signals detected by the two first detection terminals; if so, the local discharge signals detected by the two first detection terminals are continuously collected according to the preset number of collections; the discharge position is determined according to the time difference between the two first detection terminals collecting the local discharge signals each time.

[0011] In one possible implementation, the signal detection terminal is an ultra-high frequency (UHF) sensor for collecting discharge signals generated by partial discharge;

[0012] Obtain the discharge signals collected by each signal detection terminal and the time when the discharge signals arrive, including:

[0013] The discharge signal collected by each of the UHF sensors is acquired, and the timestamp of the discharge signal arriving at each of the UHF sensors is recorded to determine the time when the discharge signal arrives.

[0014] In one possible implementation, determining the maximum propagation time length between two detection terminals according to the pulse signal propagation time between the two first detection terminals includes:

[0015] Injecting a calibrated partial discharge pulse signal into a first detection terminal, the calibrated partial discharge pulse signal is used to be sent from the first detection terminal to another first detection terminal through a coaxial cable;

[0016] Determine the signal injection time of the partial discharge pulse signal and the signal reception time when another first detection terminal receives the partial discharge pulse signal;

[0017] The maximum propagation time length is determined according to the time difference between the signal injection time and the signal reception time.

[0018] In one possible implementation, the maximum propagation time length is determined by the distance between the two first detection terminals, which is expressed as:

[0019]

[0020] Wherein, k is the time stretch coefficient, v is the wave velocity of signal propagation, and l is the distance between the two first detection terminals obtained by pre-measurement.

[0021] In one possible implementation, determining whether the time for the discharge signal to reach the two first detection terminals is less than or equal to the maximum propagation time length further includes:

[0022] If the time it takes for the discharge signal to reach the two first detection terminals is greater than the maximum propagation time length, determining whether the signal strength of the discharge signal received by the two first detection terminals is lower than a detection threshold;

[0023] If so, add a signal amplifier or adjust the positions of the two first detection terminals until the strength of the signal received by the first detection terminal meets the detection threshold.

[0024] In one possible implementation, determining whether there is and only one partial discharge pulse in the discharge signals detected by the two first detection terminals further includes:

[0025] If the discharge signals detected by the two first detection terminals are both partial discharge pulses, or the discharge signals are not partial discharge pulses, feature extraction is performed on the discharge signals, including pulse width, amplitude and frequency content, to extract partial discharge signals.

[0026] In one possible implementation, determining the discharge position according to the time difference between the two first detection terminals collecting the partial discharge signal each time includes:

[0027] The time when the two first detection terminals collect the partial discharge signal each time is obtained, and the time difference when the partial discharge signal reaches the two first detection terminals is determined, which is expressed as:

[0028]

[0029] In the formula, p is the preset number of acquisitions, t i1 and t i2 is the time when the partial discharge signal reaches the two first detection terminals, and i is the sequence number of the partial discharge occurrence;

[0030] According to the time difference, the distance from the discharge position to the first detection terminal is determined, which is expressed as:

[0031]

[0032] Where l is the distance between the two first detection terminals, and v is the wave velocity of signal propagation;

[0033] The local discharge position is determined according to the position of the first detection terminal and the distance from the discharge position to the first detection terminal.

[0034] In a second aspect, the present application provides a low sampling rate GIS partial discharge locating device, including a main control circuit, a sampling module, a coaxial transmission line and at least two UHF sensors;

[0035] The UHF sensor is used to collect partial discharge signals on the GIS body;

[0036] The sampling module includes an analog-to-digital converter ADC, which is used to receive the partial discharge signal collected by the UHF sensor through the coaxial transmission line and convert the partial discharge signal from an analog signal to a digital signal;

[0037] The main control circuit is connected to the sampling module, and is used to receive the partial discharge signal converted by the sampling module, and execute the low sampling rate GIS partial discharge positioning method according to any one of claims 1 to 7.

[0038] In one possible implementation, each UHF sensor is respectively arranged at the non-metallic detection hole of the GIS pot-type insulator, and is connected to the sampling module via a coaxial transmission line, and the length of the coaxial transmission line between each UHF sensor and the sampling module is equal.

[0039] In one possible implementation, the partial discharge locating device further includes a partial discharge calibrator and an oscilloscope for determining the maximum propagation time length between two adjacent UHF sensors;

[0040] After one UHF sensor is connected to a T-shaped coaxial adapter, it is respectively connected to a partial discharge calibrator and an oscilloscope, and another UHF sensor is connected to different channels of the oscilloscope;

[0041] Injecting a pulsed partial discharge signal into a terminal of a UHF sensor connected to the partial discharge signal calibrator, and determining the waveform and arrival time of the pulsed partial discharge signal received by two UHF sensors according to an oscilloscope;

[0042] The maximum propagation time length is determined according to the difference between the arrival times of two pulse partial discharge signals.

[0043] Compared with the prior art, the technical solution provided by this application has the following beneficial effects:

[0044] The present application screens valid signals by setting a maximum propagation time length. The local discharge signal is valid only when the time difference between the discharge signal reaching the two first detection terminals is less than or equal to the maximum value, thereby filtering out false alarms caused by noise or other interference sources and improving the reliability of detection.

[0045] Whether there is only a single partial discharge pulse in the signals detected by the two first detection terminals is used as a condition for further analysis, which reduces unnecessary data processing and speeds up positioning. After confirming that the partial discharge signal is valid, the partial discharge signal is continuously collected and recorded repeatedly according to the preset number of collections. The time difference between the partial discharge signals detected by the two first detection terminals during each collection process is calculated to accurately determine the location of the partial discharge source, thereby achieving fast and accurate fault positioning, providing a strong guarantee for the safe and stable operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0047] Figure 1 A schematic diagram of the structure of a low sampling rate GIS partial discharge locating device provided in Example 1 of the present application.

[0048] Figure 2 A calibration maximum propagation time length t provided in Example 1 of the present application max Schematic diagram of .

[0049] Figure 3This is a structural schematic diagram of a GIS partial discharge locating device provided in Example 1 of the present application when a GIS body is equipped with a built-in UHF sensor.

[0050] Figure 4 This is a structural schematic diagram of a GIS partial discharge locating device when a plurality of built-in UHF sensors are installed in the GIS body provided in the first embodiment of the present application.

[0051] Figure 5 A flow chart of a low sampling rate GIS partial discharge locating method provided in Example 2 of the present application.

[0052] Figure 6 This is a schematic diagram of a partial discharge signal provided in Embodiment 2 of the present application that propagates along the GIS cavity to two first detection terminals after occurrence.

[0053] Figure numerals: 1. main control circuit; 2. sampling module; 3. coaxial transmission line; 4. ultra-high frequency sensor. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0055] Embodiment 1

[0056] See also Figure 1 , is a schematic diagram of the structure of a low sampling rate gas insulated switchgear (hereinafter referred to as GIS) partial discharge positioning device provided in Example 1 of the present application. The positioning device includes a main control circuit 1, a sampling module 2, a coaxial transmission line 3 and an ultra high frequency sensor 4 (Ultra High Frequency Sensor, hereinafter referred to as UHF sensor).

[0057] In this embodiment, at least two external ultra high frequency sensors 4 (Ultra High Frequency Sensor, hereinafter referred to as: UHF sensor 4) are pre-installed at different positions of the GIS body. Figure 1 As shown in FIG. 1 , in this embodiment, the UHF sensor 4 is installed at the position of the non-metallic detection hole of the pot-type insulator.

[0058] Taking the installation of two UHF sensors 4 as an example, after the UHF sensors 4 are installed, they are connected to the sampling module 2 with the same clock. When partial discharge occurs, the electromagnetic wave signal will propagate from near to far along the GIS cavity, and each UHF sensor 4 will receive the partial discharge signal according to the distance from the discharge point. The collected partial discharge signal is transmitted to the collection module 2 through the coaxial transmission line 3.

[0059] The coaxial transmission line 3 is composed of a long straight cylindrical wire and a coaxial conductor cylinder, and is used to transmit partial discharge signals. A concentric cylindrical gap is formed between the insulator at the center of the long straight cylindrical wire and the conductor cylinder, which is filled with dielectric material. The coaxial conductor cylinder is used to shield the signal inside the line and the interference signal outside the line, ensuring the stability of the transmission of the partial discharge signal.

[0060] The acquisition module 2 has built-in analog-to-digital converters 21 and 24 (ADC), which are used to convert the two received partial discharge signals from analog signals into digital signals that can be recognized and processed by the main control circuit 1 .

[0061] Specifically, Figure 1 As shown in the figure, the main control circuit 1 uses FPGA as the core chip to control the sampling module 2, and receives two partial discharge signals converted by the sampling module 2 to determine the partial discharge position. Specifically, the distance between each UHF sensor 4 is fixed. According to the time difference between the collected partial discharge signals reaching different discharge points, the distance difference between the discharge point and different UHF sensors can be determined to achieve the positioning of the discharge position.

[0062] In this embodiment, in order to prevent interference signals from affecting the localization results of partial discharge, the maximum propagation time length t max A set of discharge signals is considered as a valid partial discharge signal only when it is within the maximum propagation time length and the detection signals of two adjacent UHF sensors 4 have and only have one partial discharge pulse.

[0063] Specifically, Figure 2 The maximum propagation time length t shown in max The calibration process is as follows:

[0064] The two UHF sensors with the longest distance are selected as calibration objects. One of the UHF sensors 4 is connected to a T-shaped coaxial adapter, and is respectively connected to a partial discharge calibrator and an oscilloscope. The other UHF sensor 4 is connected to different channels of the same oscilloscope. In this embodiment, the two coaxial cables used by the two UHF sensors 4 to connect to the oscilloscope are of the same model and length, and the sampling rate of the oscilloscope used is higher than 10 GHz.

[0065] Inject a pulsed partial discharge signal into the terminal of the UHF sensor 4 connected to the partial discharge calibrator, and observe the waveform and arrival time of the pulsed partial discharge signal received by the two UHF sensors 4 on the oscilloscope. Set the difference in the arrival time of the two pulsed partial discharge signals as the maximum propagation time length t max .

[0066] Alternatively, the distance l between the two UHF sensors 4 can be measured and t can be calculated using the maximum propagation time length formula. max .

[0067] Among them, the maximum propagation time length formula can be expressed as:

[0068]

[0069] In the formula, k is the time stretch coefficient, which can be set according to actual conditions. In this embodiment, considering that the propagation distance of the UHF signal in the three-dimensional structure of the combined electrical appliance will be lengthened, the time stretch coefficient is set to 1.1.

[0070] It should be noted that the maximum propagation time length obtained by calibration test or measurement calculation has a scale value less than or equal to 0.1ns. However, the sampling rate of the positioning device provided in this application is 50MHz, and the time scale value is 20ns. Therefore, the t actually used is max It should be rounded up to an integer multiple of 20ns.

[0071] In addition, in order to minimize the impact of the UHF sensor 4, coaxial transmission line 3 and sampling module 2 on the detected time and avoid detection time deviation, the main core components of the UHF sensor 4, coaxial transmission line 3 and sampling module 2 in this embodiment are all of the same model and the same batch of products, and the lengths of the two coaxial transmission lines are the same. In addition, the main control crystal oscillator frequency of the main control circuit is 50MHZ, and the sampling frequency of the sampling module is also 50MHZ.

[0072] It should be noted that if the GIS body is already equipped with a built-in UHF sensor 4, there is no need to install an additional external UHF sensor 4. Figure 3 The selection and arrangement of the remaining modules are the same as above and will not be described here.

[0073] like Figure 4 As shown in FIG. 1 , a plurality of built-in UHF sensors 4 are installed in the GIS body as an example, and each two adjacent UHF sensors 4 form a positioning combination. It should be noted that all sampling modules 2 must be driven by the same main control chip.

[0074] Embodiment 2

[0075] After completing the arrangement of the GIS local discharge locating device provided in the first embodiment of the present application, if local discharge exists in the part between the two UHF sensors 4 of the GIS local discharge locating device, the electromagnetic signal of the local discharge signal will propagate successively to the two UHF sensors 4, thereby performing GIS local discharge locating based on the main control circuit 1.

[0076] See also Figure 5 , is a flow chart of a low sampling rate GIS partial discharge location method provided in Example 2 of the present application. In the embodiment of the present application, at least two signal detection terminals, namely UHF sensors, are provided on the GIS body for collecting discharge signals generated during the GIS partial discharge process.

[0077] like Figure 5 As shown in , the specific implementation steps of the above method may include:

[0078] S101. When local discharge occurs in the GIS body, the discharge signal collected by each signal detection terminal and the arrival time of the discharge signal are obtained.

[0079] This embodiment takes a plurality of UHF sensors 4 arranged on the GIS body as an example, and the UHF sensors 4 are connected to a multi-channel digital sampling device with the same clock, that is, the sampling module 2 in the first embodiment of the present application. After partial discharge occurs, the electromagnetic wave signal propagates from near to far along the GIS cavity, and each UHF sensor 4 receives the discharge signal according to the distance from the discharge position.

[0080] S102 . According to the arrival time of the discharge signal, determine the two UHF sensors 4 that first detect the discharge signal, and record them as first detection terminals.

[0081] In one achievable manner, the above time is determined by a timestamp of the arrival of the discharge signal recorded in each UHF sensor.

[0082] S103: Determine the maximum propagation time lengths corresponding to the two first detection terminals.

[0083] The maximum propagation time length is defined as t max , which is determined by the time of pulse signal propagation between the two first detection terminals. Specifically, when arranging the GIS partial discharge locating device, a calibrated partial discharge pulse signal is injected into one of the first detection terminals, and transmitted to the other first detection terminal using a coaxial cable. The maximum propagation time length is determined based on the time of injecting the calibrated partial discharge pulse signal and the time when the other first detection terminal receives the partial discharge pulse signal. For example, the maximum propagation time length can be the maximum value of the time difference between the signal injection time and the signal reception time.

[0084] Alternatively, the maximum propagation time length t max It can be determined by the distance between the two first detection terminals and can be expressed as:

[0085]

[0086] Wherein, k is the time stretch coefficient, v is the wave velocity of signal propagation 300m / μs, and l is the distance between the two first detection terminals obtained by pre-measurement.

[0087] S104, determining whether the time for the discharge signal to reach the two first detection terminals is less than or equal to the maximum propagation time length corresponding to the two first detection terminals. If yes, proceed to step 105.

[0088] In this embodiment, in order to prevent interference signals from affecting the positioning of partial discharge, a group of discharge signals is considered to be a valid partial discharge signal only if the discharge signals detected by the two first detection terminals have only one partial discharge pulse within the maximum propagation time length.

[0089] S105 , if the time it takes for the discharge signal to reach the two first detection terminals is less than or equal to the maximum propagation time length corresponding to the two first detection terminals, determine whether there is and only one local discharge pulse in the discharge signal detected by the two first detection terminals.

[0090] In other embodiments, if the time it takes for a group of discharge signals to reach the two first detection terminals exceeds the maximum propagation time length, this may mean that the signal is interfered with or there is a problem with the detection equipment. At this time, it is determined whether the signal strength of the discharge signal received by the two first detection terminals is lower than the detection threshold. If the signal strength of the discharge signal is lower than the detection threshold, a signal amplifier is added to enhance the signal. At the same time, according to the relationship between the signal strength received by the first detection terminal and the position of the first detection terminal, the position of the first detection terminal on the GIS body is adjusted so that the strength of the signal received by the first detection terminal meets the detection threshold. Optionally, the detection threshold of the signal strength can be set according to actual conditions, and this embodiment does not make specific limitations.

[0091] S106: If there is one and only one partial discharge pulse in the discharge signals detected by the two first detection terminals, continuously collect the partial discharge signals detected by the two first detection terminals according to a preset number of collection times.

[0092] In a specific application scenario, when processing partial discharge signals, if both of the discharge signals detected by the two first detection terminals are partial discharge pulses, it indicates that there are multiple discharge sources or the signal propagation paths overlap. In order to accurately locate and analyze these signals, this embodiment proposes to extract features of the discharge signals captured by the two first detection terminals, including parameters such as pulse width, amplitude, and frequency content, to distinguish different discharge types and discharge sources, thereby extracting partial discharge signals.

[0093] Considering that if only the result of a single test is used to locate the partial discharge signal, the positioning accuracy is only 3m. And the occurrence of partial discharge signals is continuous. Once the potential defect starts to stimulate partial discharge, almost every 50Hz power frequency cycle will stimulate partial discharge signals. Therefore, in the solution provided in this embodiment, multiple partial discharge signals are collected according to the preset number of collections. Optionally, the preset number of collections can be set according to the actual situation, and this embodiment does not make a specific limitation.

[0094] S107, obtaining the time when the two first detection terminals collect the partial discharge signal each time, and determining the time difference when the partial discharge signal reaches the two first detection terminals.

[0095] The arrival times of the partial discharge signals are t i1 and t i2 Where i is the sequence number of the partial discharge, and the time difference between the partial discharge signal and the two first detection terminals can be calculated as:

[0096]

[0097] Where p is the preset number of acquisitions. After acquiring partial discharge signals for p times, the time difference accuracy of partial discharge reaching different detection points can be improved by p times.

[0098] S108. Determine the distance from the discharge position to the first detection terminal according to the time difference, so as to realize local discharge positioning.

[0099] like Figure 6 As shown in , after the local discharge signal occurs, it propagates along the GIS cavity to the two first detection terminals. The time difference Δt detected by the two first detection terminals is calculated by the above formula: p Afterwards, the distance between the discharge position and the first detection terminal numbered 1 can be expressed as:

[0100]

[0101] Where l is the distance between the two first detection terminals, Δt p is the time difference from the local discharge signal to the two first detection terminals, and v is the wave speed of signal propagation, 300 m / μs.

[0102] As the number of acquisitions increases, the accuracy of the calculated distance from the discharge position to the first detection terminal will gradually increase, and the discharge position obtained by positioning will gradually converge to the actual accurate discharge position.

[0103] Compared with the prior art, the technical solution provided by this application has the following beneficial effects:

[0104] The technical solution provided in Example 2 of the present application screens valid signals by setting a maximum propagation time length. The local discharge signal is valid only when the time difference between the discharge signal reaching the two first detection terminals is less than or equal to the maximum value, thereby filtering out false alarms caused by noise or other interference sources and improving the reliability of detection.

[0105] Whether there is only a single partial discharge pulse in the signals detected by the two first detection terminals is used as a condition for further analysis, which reduces unnecessary data processing and speeds up positioning. After confirming that the partial discharge signal is valid, the partial discharge signal is continuously collected and recorded repeatedly according to the preset number of collections. The time difference between the partial discharge signals detected by the two first detection terminals during each collection process is calculated to accurately determine the location of the partial discharge source, thereby achieving fast and accurate fault location, providing a strong guarantee for the safe and stable operation of the power system.

[0106] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0107] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0108] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low sampling rate GIS partial discharge location method, wherein at least two signal detection terminals are arranged on the GIS body, characterized in that: include: When partial discharge occurs in the GIS body, the discharge signal collected by each signal detection terminal and the time when the discharge signal arrives are obtained; According to the time when the discharge signal arrives, the two UHF sensors that first detect the discharge signal are determined, and both are recorded as the first detection terminals; the maximum propagation time length between the two first detection terminals is determined, which is determined by the pulse signal propagation time between the two first detection terminals or the distance between the two first detection terminals; it is judged whether the time when the discharge signal arrives at the two first detection terminals is less than or equal to the maximum propagation time length; if it is less than or equal to, it is judged whether there is and only one local discharge pulse in the discharge signal detected by the two first detection terminals; if so, the local discharge signals detected by the two first detection terminals are continuously collected according to a preset number of collections; the discharge position is determined according to the time difference between the two first detection terminals collecting the local discharge signal each time.

2. A low sampling rate GIS partial discharge location method according to claim 1, characterized in that: The signal detection terminal is an ultra-high frequency (UHF) sensor, which is used to collect discharge signals generated by partial discharge; Obtain the discharge signals collected by each signal detection terminal and the time when the discharge signals arrive, including: The discharge signal collected by each of the UHF sensors is acquired, and the timestamp of the discharge signal arriving at each of the UHF sensors is recorded to determine the time when the discharge signal arrives.

3. A low sampling rate GIS partial discharge location method according to claim 1, characterized in that: Determining the maximum propagation time length between two detection terminals according to the pulse signal propagation time between the two first detection terminals includes: Injecting a calibrated partial discharge pulse signal into a first detection terminal, the calibrated partial discharge pulse signal is used to be sent from the first detection terminal to another first detection terminal through a coaxial cable; Determine the signal injection time of the partial discharge pulse signal and the signal reception time when another first detection terminal receives the partial discharge pulse signal; The maximum propagation time length is determined according to the time difference between the signal injection time and the signal reception time.

4. A low sampling rate GIS partial discharge location method according to claim 1, characterized in that: The maximum propagation time length is determined by the distance between the two first detection terminals, which is expressed as: Wherein, k is the time stretch coefficient, v is the wave velocity of signal propagation, and l is the distance between the two first detection terminals obtained by pre-measurement.

5. A low sampling rate GIS partial discharge location method according to claim 1, characterized in that: Determining whether the time for the discharge signal to reach the two first detection terminals is less than or equal to the maximum propagation time length further includes: If the time it takes for the discharge signal to reach the two first detection terminals is greater than the maximum propagation time length, determining whether the signal strength of the discharge signal received by the two first detection terminals is lower than a detection threshold; If so, add a signal amplifier or adjust the positions of the two first detection terminals until the strength of the signal received by the first detection terminal meets the detection threshold.

6. A low sampling rate GIS partial discharge location method according to claim 1, characterized in that: Determining whether there is and only one partial discharge pulse in the discharge signals detected by the two first detection terminals also includes: If the discharge signals detected by the two first detection terminals are both partial discharge pulses, or the discharge signals are not partial discharge pulses, feature extraction is performed on the discharge signals, including pulse width, amplitude and frequency content, to extract partial discharge signals.

7. A low sampling rate GIS partial discharge location method according to claim 1, characterized in that: Determining the discharge position according to the time difference between the two first detection terminals collecting the partial discharge signal each time, including: The time when the two first detection terminals collect the partial discharge signal each time is obtained, and the time difference when the partial discharge signal reaches the two first detection terminals is determined, which is expressed as: In the formula, p is the preset number of acquisitions, t i1 and t i2 is the time when the partial discharge signal reaches the two first detection terminals, and i is the sequence number of the partial discharge occurrence; According to the time difference, the distance from the discharge position to the first detection terminal is determined, which is expressed as: Where l is the distance between the two first detection terminals, and v is the wave velocity of signal propagation; The local discharge position is determined according to the position of the first detection terminal and the distance from the discharge position to the first detection terminal.

8. A low sampling rate GIS partial discharge locating device, characterized in that: It includes a main control circuit, a sampling module, a coaxial transmission line and at least two UHF sensors; The UHF sensor is used to collect partial discharge signals on the GIS body; The sampling module includes an analog-to-digital converter ADC, which is used to receive the partial discharge signal collected by the UHF sensor through the coaxial transmission line and convert the partial discharge signal from an analog signal to a digital signal; The main control circuit is connected to the sampling module, and is used to receive the partial discharge signal converted by the sampling module, and execute the low sampling rate GIS partial discharge positioning method according to any one of claims 1 to 7.

9. A low sampling rate GIS partial discharge locating device according to claim 8, characterized in that: Each UHF sensor is respectively arranged at the non-metallic detection hole of the GIS pot-type insulator, and is connected to the sampling module through a coaxial transmission line. The length of the coaxial transmission line between each UHF sensor and the sampling module is equal.

10. A low sampling rate GIS partial discharge locating device according to claim 8, characterized in that: The partial discharge locating device also includes a partial discharge calibrator and an oscilloscope for determining the maximum propagation time length between two adjacent UHF sensors; After one UHF sensor is connected to a T-shaped coaxial adapter, it is respectively connected to a partial discharge calibrator and an oscilloscope, and another UHF sensor is connected to different channels of the oscilloscope; Injecting a pulsed partial discharge signal into a terminal of a UHF sensor connected to the partial discharge signal calibrator, and determining the waveform and arrival time of the pulsed partial discharge signal received by two UHF sensors according to an oscilloscope; The maximum propagation time length is determined according to the difference between the arrival times of two pulse partial discharge signals.

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