Live detection device for lightning arrester

Abstract

The invention discloses a live detection device for a lightning arrester. The live detection device comprises an electric signal detection module and a data processing module, the electric signal detection module is used for detecting a voltage signal and a three-phase current signal of a lightning arrester to be detected; the data processing module is used for performing harmonic analysis on the voltage signal and the three-phase current signal detected at the same moment to obtain a fundamental wave resistive current component and a plurality of higher harmonic resistive current components; and determining the resistive current value of the lightning arrester to be detected according to the fundamental wave resistive current component and the plurality of higher harmonic resistive current components. By adopting the lightning arrester live detection device provided by the invention, automatic detection of the resistive current value of the three-phase lightning arrester can be realized without on-site long-distance wiring, and interference influences such as electric field interference, magnetic field interference and interphase interference in the measurement process are effectively reduced, so that the detection precision of the resistive current value can be improved, and the detection accuracy of the three-phase lightning arrester is improved. And the insulation performance of the lightning arrester can be timely and accurately determined.

Description

Technical Field

[0001] The invention relates to the technical field of lightning arresters, and in particular to a lightning arrester live detection device. Background Art

[0002] Metal oxide arresters (such as zinc oxide arresters) are important devices for overvoltage protection in modern power systems. Since metal oxide arresters are subjected to system voltage, overvoltage, dirt, internal moisture and other factors for a long time, their insulation performance deteriorates and their nonlinear characteristics fail, causing the arrester to age and even explode, seriously threatening the safe operation of the power grid. Therefore, testing the insulation performance of the arrester can detect and eliminate faults early and prevent accidents.

[0003] The prior art usually uses a resistive current tester to test the resistive current of a lightning arrester, so as to reflect the insulation performance of the lightning arrester through the resistive current. However, when using this method to test the lightning arrester, it is necessary to lay longer leads on site, which makes the leads easy to get tangled, resulting in the measurement process being easily affected by interference such as electric field interference, magnetic field interference, and phase interference, resulting in a large measurement error of the resistive current. In addition, due to too many leads, there is a high risk of personal safety. Summary of the invention

[0004] The present invention provides a lightning arrester live detection device, which can realize automatic detection of the resistive current value of a three-phase lightning arrester without long-distance wiring on site, effectively reducing the influence of interference such as electric field interference, magnetic field interference, phase-to-phase interference, etc. during the measurement process, thereby improving the detection accuracy of the resistive current value and helping to timely and accurately determine the insulation performance of the lightning arrester.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a lightning arrester live detection device, including an electrical signal detection module and a data processing module; The electrical signal detection module is used to detect the voltage signal and three-phase current signal of the arrester to be tested; The data processing module is used to perform harmonic analysis on the voltage signal and the three-phase current signal detected at the same time to obtain a fundamental resistive current component and a plurality of higher-order harmonic resistive current components; and determine the resistive current value of the arrester to be tested based on the fundamental resistive current component and the plurality of higher-order harmonic resistive current components.

[0006] As a preferred solution, the data processing module is used to perform harmonic analysis on the voltage signal and the three-phase current signal detected at the same time to obtain the fundamental resistive current component and several high-order harmonic resistive current components, specifically including: Performing harmonic analysis on the voltage signal and the three-phase current signal detected at the same time, obtaining the voltage fundamental wave phase angle of the voltage signal and the voltage harmonic phase angles corresponding to several higher-order harmonics, the current fundamental wave amplitude, the current fundamental wave phase angle, and the current harmonic amplitude and current harmonic phase angle corresponding to several higher-order harmonics of the three-phase current signal; Obtaining the fundamental wave resistive current component according to the current fundamental wave amplitude, the voltage fundamental wave phase angle and the current fundamental wave phase angle; According to the current harmonic amplitude, voltage harmonic phase angle and current harmonic phase angle of the same harmonic order, a plurality of high-order harmonic resistive current components are obtained.

[0007] As a preferred solution, the high-order harmonics are specifically odd-order harmonics, and the odd-order harmonics include 3rd harmonics, 5th harmonics, 7th harmonics and 9th harmonics.

[0008] As a preferred solution, the device also includes a timing module and a data acquisition module; The timing module is used to send a synchronous time signal to the data acquisition module based on satellite timing; The data acquisition module is used to synchronously trigger the electrical signal detection module based on the synchronization time signal, and collect the voltage signal and three-phase current signal detected at the current moment from the electrical signal detection module; perform signal processing on the collected voltage signal and three-phase current signal to obtain the voltage signal and three-phase current signal detected at the same moment.

[0009] As a preferred solution, the timing module includes a processor and a crystal oscillator; The timing module is used to send a synchronous time signal to the data acquisition module based on satellite timing, specifically including: Extracting a pulse-per-second signal from a time signal provided by a satellite through the processor and sending the signal to the crystal oscillator; A synchronous time signal with a frequency of 10 MHz is generated by the crystal oscillator based on the second pulse signal and sent to the data acquisition module.

[0010] As a preferred solution, the timing module is also used for: The processor extracts the time information corresponding to the pulse-per-second signal from the time signal, and based on the time information, adds a time tag to the voltage signal and the three-phase current signal detected at the current moment.

[0011] As a preferred solution, the data acquisition module includes an acquisition unit, a signal conditioning unit and an analog-to-digital conversion unit; The data acquisition module is used to synchronously trigger the electrical signal detection module based on the synchronization time signal, and collect the voltage signal and the three-phase current signal detected at the current moment from the electrical signal detection module; perform signal processing on the collected voltage signal and the three-phase current signal to obtain the voltage signal and the three-phase current signal detected at the same moment, specifically including: Synchronously triggering the electrical signal detection module based on the synchronization time signal by the acquisition unit, and acquiring the voltage signal and the three-phase current signal detected at the current moment from the electrical signal detection module; The signal conditioning unit performs signal conditioning on the collected voltage signal and three-phase current signal; The voltage signal and the three-phase current signal after signal conditioning are converted into analog-to-digital signals by the analog-to-digital conversion unit to obtain the voltage signal and the three-phase current signal detected at the same time.

[0012] As a preferred solution, the device further comprises a wireless communication module; the data acquisition module is communicatively connected with the electrical signal detection module via the wireless communication module.

[0013] As a preferred solution, the electrical signal detection module includes a voltage detection unit and a plurality of current detection units; The voltage detection unit is arranged on the secondary side of the voltage transformer of the lightning arrester to be tested, and the voltage detection unit is used to detect the voltage signal of the lightning arrester to be tested; The plurality of current detection units are respectively arranged on the three-phase arrester units of the arrester to be tested, and the plurality of current detection units are used to detect the voltage signal and the three-phase current signal of the arrester to be tested.

[0014] As a preferred solution, the device further comprises an insulation performance determination module; The insulation performance determination module is used to obtain the insulation performance determination result of the arrester to be tested based on the ratio between the resistive current value and the full current value corresponding to the three-phase current signal and a preset ratio threshold.

[0015] Compared with the prior art, the beneficial effect of the embodiments of the present invention is that it can realize the automatic detection of the resistive current value of the three-phase lightning arrester without the need for long-distance wiring on site, effectively reducing the interference effects such as electric field interference, magnetic field interference, phase-to-phase interference, etc. during the measurement process, thereby improving the detection accuracy of the resistive current value, helping to timely and accurately determine the insulation performance of the lightning arrester, and can greatly reduce personal safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a preferred embodiment of the lightning arrester live detection device in the present invention; Figure 2 It is a structural schematic diagram of another preferred embodiment of the lightning arrester live detection device in the present invention; Figure 3 is a schematic diagram of the arrangement structure of a voltage detection unit and a current detection unit in an embodiment of the present invention; Among them, 101, electrical signal detection module; 102, data processing module; 103, timing module; 104, data acquisition module; 105, processor; 106, crystal oscillator; 107, acquisition unit; 108, signal conditioning unit; 109, analog-to-digital conversion unit; 110, wireless communication module; 111, insulation performance judgment module; 112, voltage detection unit; 113, current detection unit. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] In the description of this application, the terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0019] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used herein are only for illustrative purposes, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0020] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0021] See also Figure 1 , an embodiment of the present invention provides a lightning arrester live detection device, including an electrical signal detection module 101 and a data processing module 102; The electrical signal detection module 101 is used to detect the voltage signal and three-phase current signal of the arrester to be tested; The data processing module 102 is used to perform harmonic analysis on the voltage signal and the three-phase current signal detected at the same time to obtain a fundamental resistive current component and a plurality of higher-order harmonic resistive current components; and determine the resistive current value of the arrester to be tested based on the fundamental resistive current component and the plurality of higher-order harmonic resistive current components.

[0022] Specifically, for a three-phase lightning arrester such as a zinc oxide lightning arrester, it usually includes an A-phase lightning arrester unit, a B-phase lightning arrester unit, and a C-phase lightning arrester unit, and the resistive current tester used in the prior art can only measure a single phase separately, and cannot achieve synchronous measurement of the three-phase lightning arrester unit, and the test efficiency is low and the test accuracy is low. The electrical signal detection module 101 in this embodiment is not limited to detecting only the voltage signal and the three-phase current signal of a single lightning arrester to be tested, and it can be assembled on multiple lightning arresters to be tested to synchronously measure the voltage signals and the three-phase current signals of multiple lightning arresters to be tested. Further, this embodiment performs fast Fourier transform on the voltage signal and three-phase current signal detected at the same time, so as to perform harmonic analysis on the voltage signal and three-phase current signal detected at the same time, and identify the fundamental amplitude, fundamental phase angle and harmonic amplitude and harmonic phase angle of the voltage signal and the three-phase current signal. It is worth noting that the higher harmonic refers to a sine wave with a frequency higher than an integer multiple of the fundamental frequency, such as the frequency of the 2nd harmonic is 2 times the fundamental frequency, the frequency of the 5th harmonic is 5 times the fundamental frequency, etc. This embodiment will not be described in detail here. Based on the results of each harmonic analysis, the fundamental resistive current component and several higher harmonic resistive current components can be further calculated. Further, for the arrester unit corresponding to each phase line, according to the sum of its fundamental resistive current component and several higher harmonic resistive current components, the resistive current value of the arrester to be tested can be clearly determined.

[0023] As a preferred solution, the data processing module 102 is used to perform harmonic analysis on the voltage signal and the three-phase current signal detected at the same time to obtain the fundamental resistive current component and several high-order harmonic resistive current components, specifically including: Performing harmonic analysis on the voltage signal and the three-phase current signal detected at the same time, obtaining the voltage fundamental wave phase angle of the voltage signal and the voltage harmonic phase angles corresponding to several higher-order harmonics, the current fundamental wave amplitude, the current fundamental wave phase angle, and the current harmonic amplitude and current harmonic phase angle corresponding to several higher-order harmonics of the three-phase current signal; Obtaining the fundamental wave resistive current component according to the current fundamental wave amplitude, the voltage fundamental wave phase angle and the current fundamental wave phase angle; According to the current harmonic amplitude, voltage harmonic phase angle and current harmonic phase angle of the same harmonic order, a plurality of high-order harmonic resistive current components are obtained.

[0024] Specifically, after performing harmonic analysis on the voltage signal and the three-phase current signal detected at the same time, the following frequency domain signal is obtained: In the voltage signal, the voltage fundamental phase angle is represented by θ1, and the voltage harmonic phase angle corresponding to the nth higher harmonic is represented by θ n , n is the harmonic order of the higher harmonic, that is, the ratio between the frequency of the current higher harmonic and the fundamental frequency; in the current signal, the current fundamental amplitude is expressed as I1, the current fundamental phase angle is expressed as φ1, and the current harmonic amplitude corresponding to the nth higher harmonic is expressed as I n , the current harmonic phase angle is expressed as φ n Furthermore, for the arrester unit corresponding to each phase line, according to the current fundamental wave amplitude I1, voltage fundamental wave phase angle θ1 and current fundamental wave phase angle φ1, the expression: I R1 =I1×cos(φ1-θ1), calculate the fundamental wave resistive current component I R1 ; According to the current harmonic amplitude I with the same harmonic order n 、Voltage harmonic phase angle θ n and current harmonic phase angle φ n , through the expression: I Rn =I n ×cos(φ n -θ n ), calculate and obtain the nth high-order harmonic resistive current component I Rn The calculation method for the resistive current value in this embodiment can effectively and accurately calculate the resistive current of the arrester, which makes up for the fact that the fundamental wave method completely ignores the influence of the higher harmonic resistive current. It can not only find the increase of the fundamental wave resistive current caused by moisture in the arrester to be tested, but also find the increase of the higher harmonic resistive current caused by the aging of the valve plate in the arrester to be tested.

[0025] As a preferred solution, the high-order harmonics are specifically odd-order harmonics, and the odd-order harmonics include 3rd harmonics, 5th harmonics, 7th harmonics and 9th harmonics.

[0026] Specifically, the high-order harmonics considered in this embodiment when calculating the resistive current value are odd harmonics. It can be understood that odd harmonics appear more frequently and are more harmful in the power system. Therefore, in actual measurements, more attention is usually paid to odd harmonics. Even harmonics have symmetrical waveforms and relatively less harm, so the necessity of measuring them is relatively low. In addition, many power systems or equipment have good attenuation capabilities for even harmonics, while odd harmonics are more easily transmitted and have an impact. In addition, this embodiment further limits the odd harmonics considered to include 3rd harmonic, 5th harmonic, 7th harmonic and 9th harmonic. It can be understood that the higher the order of the harmonic, the smaller its amplitude is usually. Therefore, the high-order harmonics with higher harmonic orders have relatively little impact on the power system. Among all the harmonics, the amplitude of the 3rd harmonic is usually the largest, and the amplitudes of the 5th harmonic, 7th harmonic and 9th harmonic decrease successively. The impact of the 3rd harmonic, 5th harmonic, 7th harmonic and 9th harmonic on the power system is also relatively large. Therefore, the 3rd harmonic, 5th harmonic, 7th harmonic and 9th harmonic are the key points considered when calculating the resistive current value.

[0027] As a preferred solution, the device further includes a timing module 103 and a data acquisition module 104; The timing module 103 is used to send a synchronization time signal to the data acquisition module 104 based on satellite timing; The data acquisition module 104 is used to synchronously trigger the electrical signal detection module 101 based on the synchronization time signal, and collect the voltage signal and three-phase current signal detected at the current moment from the electrical signal detection module 101; perform signal processing on the collected voltage signal and three-phase current signal to obtain the voltage signal and three-phase current signal detected at the same moment.

[0028] Specifically, Figure 2As shown, the lightning arrester live detection device in this embodiment also includes a timing module 103 and a data acquisition module 104. Specifically, the satellite timing synchronization has the characteristics of high precision, all-weather and low cost, and can well realize the requirements of remote synchronous data acquisition. The timing module 103 can communicate with the satellite through a built-in satellite receiving chip, such as a GPS receiving chip, a Beidou receiving chip, etc., to determine the synchronous time signal based on the satellite timing and send it to the data acquisition module 104. It can be understood that the synchronous time signal is used to instruct the data acquisition module 104 to synchronously collect the voltage signal and three-phase current signal of the lightning arrester to be tested, so as to ensure the accuracy and consistency of the data. Further, the data acquisition module 104 synchronously triggers the electrical signal detection module 101 based on the received synchronous time signal, so that the voltage signal and the three-phase current signal of each lightning arrester to be tested can be synchronously collected at the same time and the signal processing is performed, so as to facilitate the subsequent calculation and processing of the resistive current value.

[0029] As a preferred solution, the timing module 103 includes a processor 105 and a crystal oscillator 106; The timing module 103 is used to send a synchronization time signal to the data acquisition module 104 based on satellite timing, specifically including: The processor 105 extracts a pulse-per-second signal from the time signal provided by the satellite and sends the pulse-per-second signal to the crystal oscillator 106; The crystal oscillator 106 generates a synchronous time signal with a frequency of 10 MHz based on the second pulse signal and sends it to the data acquisition module 104 .

[0030] Specifically, the timing module 103 in this embodiment further includes a processor 105 and a crystal oscillator 106. It can be understood that the processor 105 is used to extract a second pulse signal from the time signal provided by the satellite. The second pulse signal is a high-precision time synchronization signal. It uses the satellite's timing function to ensure that the leading edge of each pulse accurately corresponds to the international standard time, with an error of no more than 1 microsecond. After obtaining the second pulse signal, the processor 105 sends it to the crystal oscillator 106. The crystal oscillator 106 is used to generate a stable synchronous time signal with a frequency of 10 MHz based on the received second pulse signal and send it to the data acquisition module 104, so that the data acquisition module 104 uses the synchronous time signal provided by the crystal oscillator 106 to collect the analog electrical signals of the lightning arrester to be tested, namely the voltage signal and the three-phase current signal. In other words, when it is necessary to collect the three-phase current signal and voltage signal of the lightning arrester to be tested, we will wait for the pulse leading edge of the second pulse signal to arrive, and then start the collection process of the three-phase current signal and voltage signal at the same time. Since all collection operations start at the same time point, it can ensure that the collected three-phase current signal and voltage signal are synchronized, providing an accurate basis for subsequent data analysis and processing.

[0031] In one of the preferred embodiments, the crystal oscillator 106 specifically adopts a constant temperature crystal oscillator. Considering that the existing sampling circuit generally performs sampling under the control of the internal timer interrupt, but the external crystal oscillator used by the single-chip microcomputer is not stable, the synchronization error of the synchronous sampling controlled by this scheme exceeds 1s. Therefore, a high-stability crystal oscillator with temperature compensation is selected as the sampling clock.

[0032] As a preferred solution, the timing module 103 is also used for: The processor 105 extracts the time information corresponding to the pulse-per-second signal from the time signal, and based on the time information, adds a time tag to the voltage signal and the three-phase current signal detected at the current moment.

[0033] Specifically, this embodiment combines the second pulse signal and its corresponding time information to realize the synchronous analysis of the three-phase current signal and the voltage signal. Specifically, the processor 105 is also used to extract the time information corresponding to the second pulse signal from the time signal. It can be understood that each second pulse signal corresponds precisely to the current international standard time, and the time information corresponding to the second pulse signal is actually the time information output through the serial port, which is given between the second pulse signals to illustrate the international standard time corresponding to the second pulse signal, including year, month, day, hour, minute, and second. Therefore, when the voltage signal and the three-phase current signal are collected based on the current second pulse signal, the corresponding time mark can be added to the collected signal based on the time information, so that each set of data has an accurate time mark, and it can be clearly known at what time point the data was collected. This is very important for subsequent data analysis and processing, because the time interval and sequence between each set of data can be accurately known.

[0034] It is worth noting that there is a lot of electromagnetic interference and inductive electrical interference in the measurement work carried out in the substation. These interferences will affect the measurement results of the resistive current of the metal oxide arrester with the change of time and space. Satellite synchronization technology helps to identify and eliminate this interference through precise time control, so as to obtain a more realistic resistive current value. Synchronous measurement can accurately evaluate the status of each arrester to be tested, timely discover potential problems, and accurately reflect the health status of the arrester to be tested. Using satellite signal synchronization, it is possible to achieve synchronous measurement of multiple (or even all) arresters in the substation. By eliminating common mode interference, the resistive current of each arrester can be measured more accurately, so as to more accurately evaluate its aging condition, which is helpful for the health monitoring of the entire system. Accurate measurement results can help operation and maintenance personnel identify metal oxide arresters that need maintenance or replacement, thereby improving the efficiency of maintenance work.

[0035] As a preferred solution, the data acquisition module 104 includes an acquisition unit 107, a signal conditioning unit 108 and an analog-to-digital conversion unit 109; The data acquisition module 104 is used to synchronously trigger the electrical signal detection module 101 based on the synchronization time signal, and collect the voltage signal and three-phase current signal detected at the current moment from the electrical signal detection module 101; perform signal processing on the collected voltage signal and three-phase current signal to obtain the voltage signal and three-phase current signal detected at the same moment, specifically including: The acquisition unit 107 synchronously triggers the electrical signal detection module 101 based on the synchronization time signal, and acquires the voltage signal and the three-phase current signal detected at the current moment from the electrical signal detection module 101; The signal conditioning unit 108 performs signal conditioning on the collected voltage signal and three-phase current signal; The analog-to-digital conversion unit 109 performs analog-to-digital conversion on the voltage signal and the three-phase current signal after signal conditioning to obtain the voltage signal and the three-phase current signal detected at the same time.

[0036] Specifically, the data acquisition module 104 in this embodiment further includes an acquisition unit 107, a signal conditioning unit 108 and an analog-to-digital conversion unit 109. It can be understood that since the voltage signal and the three-phase current signal collected by the acquisition unit 107 may contain noise or interference, the signal conditioning unit 108 is used to perform signal conditioning on the voltage signal and the three-phase current signal collected by the acquisition unit 107, including amplification, filtering, isolation and other means to improve the quality and stability of the signal. Furthermore, since the initially collected voltage signal and the three-phase current signal are analog signals, in order to facilitate the subsequent calculation and processing of the resistive current value, the analog-to-digital conversion unit 109 is required to convert the voltage signal and the three-phase current signal after signal conditioning from analog signals to digital signals to ensure that the signal changes can be accurately captured and provide high-precision digital signal output.

[0037] In a preferred embodiment, the data acquisition module 104 may also include an SRAM cache unit, which is used to provide high-speed data storage and reading services. The voltage signal and three-phase current signal after signal processing can be temporarily stored in the SRAM cache unit to ensure the continuity and integrity of the data, while improving the response speed and stability of the system.

[0038] As a preferred solution, the device further includes a wireless communication module 110 ; the data acquisition module 104 is communicatively connected with the electrical signal detection module 101 via the wireless communication module 110 .

[0039] Specifically, in order to avoid the heavy on-site communication cable laying work caused by the synchronous collection of electrical signals of multiple lightning arresters to be tested, the lightning arrester live detection device in this embodiment also includes a wireless communication module 110, so that the electrical signal detection module 101 can directly send the detected voltage signal and three-phase current signal to the data acquisition module 104 through wireless communication for further signal processing, which has the advantages of strong emergency response, suitable for data transmission of large-scale distributed equipment, and simple and convenient use. In order to minimize the workload of live detection operations on site, the timing module 103, data acquisition module 104, wireless communication module 110, and data processing module 102 in this embodiment can adopt an integrated design architecture. In this embodiment, the communication distance of the wireless communication module 110 can reach 500m in an open area, and the communication rate is at least 2MB / s.

[0040] In an optional embodiment, the device also includes a power module, which specifically uses a large-capacity lithium-ion battery. It can work continuously for about 6 hours on a single charge, thereby ensuring that the lightning arrester power detection device has sufficient battery life without the need for an additional external power supply, thereby improving flexibility of use.

[0041] As a preferred solution, the electrical signal detection module 101 includes a voltage detection unit 112 and a plurality of current detection units 113; The voltage detection unit 112 is arranged on the secondary side of the voltage transformer of the lightning arrester to be tested, and the voltage detection unit 112 is used to detect the voltage signal of the lightning arrester to be tested; The plurality of current detection units 113 are respectively arranged in the three-phase arrester units of the arrester to be tested, and the plurality of current detection units 113 are used to detect the voltage signal and the three-phase current signal of the arrester to be tested.

[0042] Specifically, Figure 3 As shown, the voltage detection unit 112 is fixedly installed on the secondary side of the voltage transformer, connected to the voltage transformer through a lead, and used to monitor the voltage of the voltage transformer online, and when there is a need to measure the resistive current, it responds to the measurement request of the current detection unit 113. The voltage detection unit 112 is fixed after the wiring is installed once, and there is no need to repeat the wiring when performing measurement work in the future. The current detection unit 113 is made in a distributed form, and can perform single interval three-phase synchronous measurement, multi-group interval synchronous measurement, and full-station synchronous measurement according to the needs of on-site lightning arrester live detection. During measurement, the data acquisition module 104 sends a measurement command to the voltage detection unit 112 and each current detection unit 113 through wireless communication. After receiving the measurement command, each voltage detection unit 112 and current detection unit 113 synchronously measures the voltage signal and the three-phase current signal, and then sends the measured data to the data acquisition module 104 through wireless communication.

[0043] In a preferred embodiment, the current detection unit 113 can be assembled on the arrester unit corresponding to any phase line by magnetic attraction.

[0044] As a preferred solution, the device further includes an insulation performance determination module 111; The insulation performance determination module 111 is used to obtain the insulation performance determination result of the arrester to be tested based on the ratio between the resistive current value and the full current value corresponding to the three-phase current signal and a preset ratio threshold.

[0045] Specifically, after using the electrical signal detection module 101 to detect and obtain the current signal of the lightning arrester unit corresponding to each phase line, the total current of the lightning arrester unit corresponding to each phase line can be determined. It can be understood that under normal circumstances, the resistive current value of the metal oxide lightning arrester accounts for approximately 10%~20% of the total current. Therefore, this embodiment can pre-set a ratio threshold, such as 25%~40%. When the insulation performance judgment module 111 detects that the calculated resistive current value is greater than the preset ratio threshold, it indicates that the lightning arrester to be tested is seriously contaminated or seriously damp inside, and therefore it is determined that its insulation performance is poor and needs maintenance or replacement.

[0046] An arrester live detection device provided by an embodiment of the present invention can realize automatic detection of the resistive current value of a three-phase arrester without the need for long-distance on-site wiring, effectively reducing the influence of interference such as electric field interference, magnetic field interference, and phase-to-phase interference during the measurement process, thereby improving the detection accuracy of the resistive current value and helping to promptly and accurately determine the insulation performance of the arrester.

[0047] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A lightning arrester live detection device, characterized in that: It includes an electrical signal detection module and a data processing module; The electrical signal detection module is used to detect the voltage signal and three-phase current signal of the arrester to be tested; The data processing module is used to perform harmonic analysis on the voltage signal and the three-phase current signal detected at the same time to obtain a fundamental resistive current component and a plurality of higher harmonic resistive current components; The resistive current value of the arrester to be tested is determined according to the fundamental resistive current component and a plurality of the higher harmonic resistive current components.

2. The lightning arrester live detection device according to claim 1, characterized in that: The data processing module is used to perform harmonic analysis on the voltage signal and the three-phase current signal detected at the same time to obtain the fundamental resistive current component and several high-order harmonic resistive current components, specifically including: Performing harmonic analysis on the voltage signal and the three-phase current signal detected at the same time, obtaining the voltage fundamental wave phase angle of the voltage signal and the voltage harmonic phase angles corresponding to several higher-order harmonics, the current fundamental wave amplitude, the current fundamental wave phase angle, and the current harmonic amplitude and current harmonic phase angle corresponding to several higher-order harmonics of the three-phase current signal; Obtaining the fundamental wave resistive current component according to the current fundamental wave amplitude, the voltage fundamental wave phase angle and the current fundamental wave phase angle; According to the current harmonic amplitude, voltage harmonic phase angle and current harmonic phase angle of the same harmonic order, a plurality of high-order harmonic resistive current components are obtained.

3. The lightning arrester live detection device according to claim 2, characterized in that: The high-order harmonics are specifically odd-order harmonics, and the odd-order harmonics include 3rd harmonics, 5th harmonics, 7th harmonics and 9th harmonics.

4. The lightning arrester live detection device according to claim 1, characterized in that: The device also includes a timing module and a data acquisition module; The timing module is used to send a synchronous time signal to the data acquisition module based on satellite timing; The data acquisition module is used to synchronously trigger the electrical signal detection module based on the synchronization time signal, and collect the voltage signal and three-phase current signal detected at the current moment from the electrical signal detection module; perform signal processing on the collected voltage signal and three-phase current signal to obtain the voltage signal and three-phase current signal detected at the same moment.

5. The lightning arrester live detection device according to claim 4, characterized in that: The timing module includes a processor and a crystal oscillator; The timing module is used to send a synchronous time signal to the data acquisition module based on satellite timing, specifically including: Extracting a pulse-per-second signal from a time signal provided by a satellite through the processor and sending the signal to the crystal oscillator; A synchronous time signal with a frequency of 10 MHz is generated by the crystal oscillator based on the second pulse signal and sent to the data acquisition module.

6. The lightning arrester live detection device according to claim 5, characterized in that: The timing module is also used for: The processor extracts the time information corresponding to the pulse-per-second signal from the time signal, and based on the time information, adds a time tag to the voltage signal and the three-phase current signal detected at the current moment.

7. The lightning arrester live detection device according to claim 4, characterized in that: The data acquisition module includes an acquisition unit, a signal conditioning unit and an analog-to-digital conversion unit; The data acquisition module is used to synchronously trigger the electrical signal detection module based on the synchronization time signal, and collect the voltage signal and the three-phase current signal detected at the current moment from the electrical signal detection module; perform signal processing on the collected voltage signal and the three-phase current signal to obtain the voltage signal and the three-phase current signal detected at the same moment, specifically including: Synchronously triggering the electrical signal detection module based on the synchronization time signal by the acquisition unit, and acquiring the voltage signal and the three-phase current signal detected at the current moment from the electrical signal detection module; The signal conditioning unit performs signal conditioning on the collected voltage signal and three-phase current signal; The voltage signal and the three-phase current signal after signal conditioning are converted into analog-to-digital signals by the analog-to-digital conversion unit to obtain the voltage signal and the three-phase current signal detected at the same time.

8. The lightning arrester live detection device according to claim 4, characterized in that: The device also includes a wireless communication module; the data acquisition module is communicatively connected with the electrical signal detection module via the wireless communication module.

9. The lightning arrester live detection device according to claim 1, characterized in that: The electrical signal detection module includes a voltage detection unit and a plurality of current detection units; The voltage detection unit is arranged on the secondary side of the voltage transformer of the lightning arrester to be tested, and the voltage detection unit is used to detect the voltage signal of the lightning arrester to be tested; The plurality of current detection units are respectively arranged on the three-phase arrester units of the arrester to be tested, and the plurality of current detection units are used to detect the voltage signal and the three-phase current signal of the arrester to be tested.

10. The lightning arrester live detection device according to claim 1, characterized in that: The device also includes an insulation performance determination module; The insulation performance determination module is used to obtain the insulation performance determination result of the arrester to be tested based on the ratio between the resistive current value and the full current value corresponding to the three-phase current signal and a preset ratio threshold.

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