A GIS electromagnetic voltage transformer field induction withstand voltage test system and method

Abstract

A GIS electromagnetic voltage transformer field induction withstand voltage test system and method, including an electromagnetic voltage transformer secondary side winding including an auxiliary winding and a plurality of non-assisted windings; a variable frequency power supply unit connected with the electromagnetic voltage transformer secondary side auxiliary winding, for outputting a continuous adjustable sine wave voltage; a tunable resonance compensation inductance unit containing a plurality of inductance modules, each inductance module being respectively connected in parallel with an electromagnetic voltage transformer secondary side winding, and the inductance of each inductance module being adjustable; a multi-parameter monitoring unit for respectively collecting voltage effective value, current effective value and power factor data of each secondary side winding in real time; and an intelligent control unit for dynamically adjusting the output frequency of the variable frequency power supply unit and the inductance of the tunable resonance compensation inductance unit according to the data monitored by the multi-parameter monitoring unit. The application ensures accurate conversion of primary side withstand voltage value and improves the reliability of insulation test.

Description

Technical Field

[0001] This invention belongs to the field of withstand voltage testing technology for power system equipment, and more specifically, relates to a field induction withstand voltage testing system and method for electromagnetic voltage transformers used in GIS. Background Technology

[0002] Electromagnetic voltage transformers are core electrical equipment in GIS (Gas Insulated Switchgear) systems, and their insulation performance directly determines the safe and stable operation of the power system. To verify the withstand strength of the transformer's insulation medium, an induced withstand voltage test must be conducted after on-site installation. Current standards require the primary winding to withstand 80% of the factory test voltage.

[0003] In existing technologies, there are several technical bottlenecks in the field induced withstand voltage testing of electromagnetic voltage transformers within GIS systems: 1. Due to the limited on-site testing environment, it is impossible to deploy reactance compensation components on the primary side, which leads to a sharp increase in capacitive current caused by stray capacitance. This can easily exceed the rated carrying current of the secondary winding, causing the winding to overheat and be damaged. 2. When using a fixed frequency (such as 150Hz) for testing, it is easy to induce magnetic saturation of the iron core or system resonance, which seriously affects the accuracy of the test results and the safety of equipment operation. 3. Traditional testing methods require the construction of complex tooling or the disassembly of equipment, and are only applicable to the scenario of a complete substation shutdown, which cannot meet the testing requirements of single busbar rotational shutdown operations; 4. The effect of capacity rise was not fully considered during the test, which led to a deviation in the calculation of the primary side withstand voltage value and affected the reliability of the insulation performance assessment.

[0004] 5. The induced withstand voltage range under single busbar power outage conditions includes the electromagnetic voltage transformer and its connected conductor gas chamber. The capacitance is much larger than that of the transformer itself, and the requirements for withstand voltage compensation capability are higher. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a field induction withstand voltage testing system and method for electromagnetic voltage transformers used in GIS.

[0006] The present invention adopts the following technical solution.

[0007] The first aspect of this invention proposes a field inductive withstand voltage test system for electromagnetic voltage transformers used in GIS, comprising a frequency converter power supply unit, an adjustable resonant compensation inductor unit, a multi-parameter monitoring unit, and an intelligent control unit, specifically as follows: The secondary winding of an electromagnetic voltage transformer includes an auxiliary winding and several non-auxiliary windings. The frequency converter power supply unit is connected to the secondary auxiliary winding of the electromagnetic voltage transformer to output a continuously adjustable sine wave voltage. The adjustable resonant compensation inductor unit includes multiple inductor modules, each inductor module being connected in parallel with the secondary winding of an electromagnetic voltage transformer, and the inductance of each inductor module is adjustable; The multi-parameter monitoring unit includes multiple voltage sensing modules, current sensing modules, and power factor detection modules, which respectively collect the effective voltage value, effective current value, and power factor data of each secondary winding in real time. The intelligent control unit is communicatively connected to the frequency converter, the adjustable resonant compensation inductor, and the multi-parameter monitoring unit, respectively, and is used to dynamically adjust the output frequency of the frequency converter and the inductance of the adjustable resonant compensation inductor based on the data monitored by the multi-parameter monitoring unit.

[0008] Preferably, each inductor module is equipped with a multi-position tap structure, which allows for adjustment of the inductance of different phase lengths by adjusting the tap position.

[0009] Preferably, the isolating switch of the GIS bus is opened, and the tail end of the primary winding of the electromagnetic voltage transformer, the equipment support, the shell and the iron core are reliably grounded. The tail ends of all secondary windings of the electromagnetic voltage transformer are grounded, and the head end of the uncompensated winding is kept in a floating state. The uncompensated winding is the secondary winding of the electromagnetic voltage transformer. Adjust the test frequency and voltage amplitude of the variable frequency power supply output, calculate the compensation inductance based on the reading of the secondary winding current of any electromagnetic voltage transformer, and configure the tap position of each inductor module in the adjustable resonant compensation inductor unit so that the total inductance value of all inductor modules reaches the compensation inductance. Keeping the amplitude constant, adjust the output frequency converter voltage of the frequency converter power supply, and detect the power factor of the secondary winding of each electromagnetic voltage transformer. If the power factor is not in the set range, adjust the corresponding inductor module until the power factor is in the set range. Adjust the frequency converter to perform a stepped voltage boost. After the stepped voltage boost is completed, the previously set withstand voltage time is used. If the insulation medium of the electromagnetic voltage transformer does not break down within the set withstand voltage time, and the voltage and current waveforms of all windings on the secondary side of the electromagnetic voltage transformer do not change abruptly, and the power factor remains within the set range, then the corresponding electromagnetic voltage transformer is deemed to have passed the induced withstand voltage test; otherwise, it is deemed to be unqualified.

[0010] Preferably, the set test frequency is specifically: If, during the process of calculating the compensation inductance based on the secondary winding current of any electromagnetic voltage transformer, or during the process of configuring the tap position of the adjustable resonant compensation inductor unit to make the corresponding inductor module reach the compensation inductance, core saturation is detected, the frequency is adjusted to be between the second and third frequency thresholds. The first frequency is less than or equal to the rated frequency, the second frequency and the third frequency are both greater than or equal to the rated frequency, and the second frequency is less than the third frequency.

[0011] Preferably, the step of calculating the compensation inductance based on the read secondary winding current of any electromagnetic voltage transformer specifically involves: The amplitude is set to the rated voltage. The input capacitive reactance value is obtained by dividing the rated voltage by the product of the ratio of the secondary winding current of the corresponding electromagnetic voltage transformer to the number of turns on the primary and secondary sides. Different capacitance increase factors are set for different voltage levels to obtain the capacitance increase factor corresponding to the voltage level of the electromagnetic voltage transformer; The target inductive reactance is obtained by multiplying the input capacitive reactance value by the capacitive rise factor corresponding to the electromagnetic voltage transformer. The target inductive reactance value is then divided by 2π and then by the set test frequency to obtain the compensation inductance.

[0012] Preferably, the stepped voltage boost is specifically as follows: Phase 1: Apply voltage to the ratio of the system's highest voltage Um to √3, and continue for the first set period; Second stage: The second cycle involves boosting the voltage to the system's highest voltage Um and maintaining the system's highest voltage Um continuously. Third stage: Increase the voltage to the withstand voltage value U f and maintain the withstand voltage value U f The third cycle is continuously set, and the third cycle is calculated as 120 multiplied by the rated frequency f. n With test frequency f S If the product of the two values ​​is not less than the set time threshold, then the product of the two values ​​is used as the third cycle; otherwise, the set time threshold is used as the third cycle.

[0013] Preferably, during the stepped voltage boost process, if the current of any electromagnetic voltage transformer's secondary winding exceeds the set current that the secondary winding can withstand, or if the voltage of any electromagnetic voltage transformer's secondary auxiliary winding or any winding on the secondary side shows a voltage surge or resonance characteristic signal, the voltage boost is paused and the inductance of each inductor module is adjusted until the current of each electromagnetic voltage transformer's secondary winding does not exceed the set current that the secondary winding can withstand. Once the voltage of the electromagnetic voltage transformer's secondary auxiliary winding or any winding on the secondary side has not shown a voltage surge or resonance characteristic signal, the stepped voltage boost continues.

[0014] Preferably, the occurrence of voltage abrupt change or resonance characteristic signal specifically refers to: If the absolute value of the rate of change of the voltage amplitude compared to the voltage amplitude at the previous moment exceeds a set threshold, or if the total harmonic distortion rate calculated after performing a Fourier transform of the voltage signal or the set subharmonic content rate exceeds a set threshold, then a voltage sudden change or resonance characteristic signal is determined to have occurred.

[0015] A third aspect of the invention provides an apparatus comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor performing steps of the field induced withstand voltage test method for electromagnetic voltage transformers for GIS as described in the first aspect of the invention.

[0016] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, uses the steps of the on-site induced withstand voltage test method for electromagnetic voltage transformers for GIS described in the first aspect of the present invention.

[0017] The beneficial effects of this invention are that, compared with the prior art, 1. Adaptable to on-site rotating shutdown scenarios: No need to disassemble the current transformer or build complex tooling; testing can be carried out simply by opening the busbar isolating switch, avoiding the process risks brought about by installation tooling. 2. Precise compensation for stray capacitance: By pre-testing and measuring the capacitive reactance value, the precise configuration of the compensation inductor is achieved, effectively reducing the secondary current and preventing overheating damage to the winding; 3. Avoid saturation and resonance risks: The test frequency is limited to the range of 120Hz~300Hz to prevent excessive core saturation current caused by low frequency and avoid core overheating caused by high frequency. At the same time, the resonance phenomenon is suppressed by real-time monitoring of power factor. 4. Correcting the effect of capacity rise: Set different capacity rise coefficients according to different voltage levels to ensure accurate conversion of primary side withstand voltage value and improve the reliability of insulation assessment; 5. Safe and controllable operation: The stepped voltage boosting process is combined with multiple protection mechanisms (overcurrent protection, resonance protection) to fully protect personal and equipment safety. Attached Figure Description

[0018] Figure 1 This is a framework diagram of the field inductive withstand voltage test system for electromagnetic voltage transformers used in GIS according to the present invention; Figure 2 This is a schematic diagram of a stepped boost type. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0020] like Figure 1 As shown, Embodiment 1 of the present invention proposes a field induced withstand voltage test system for electromagnetic voltage transformers used in GIS. The system includes a frequency converter power supply unit, an adjustable resonant compensation inductor unit, a multi-parameter monitoring unit, and an intelligent control unit, specifically: The secondary winding of an electromagnetic voltage transformer includes an auxiliary winding and several non-auxiliary windings. The frequency converter power supply unit is connected to the secondary auxiliary winding of the electromagnetic voltage transformer to output a continuously adjustable sine wave voltage. The adjustable resonant compensation inductor unit includes multiple inductor modules, each inductor module being connected in parallel with the secondary winding of an electromagnetic voltage transformer, and the inductance of each inductor module is adjustable; The multi-parameter monitoring unit includes multiple voltage sensing modules, current sensing modules, and power factor detection modules, which respectively collect the effective voltage value, effective current value, and power factor data of each secondary winding in real time. The intelligent control unit is communicatively connected to the frequency converter, the adjustable resonant compensation inductor, and the multi-parameter monitoring unit, respectively, and is used to dynamically adjust the output frequency of the frequency converter and the inductance of the adjustable resonant compensation inductor based on the data monitored by the multi-parameter monitoring unit.

[0021] Specifically, the components used in this invention are as follows: 1. Variable frequency power supply unit: It adopts a push-pull amplifier type variable frequency power supply without partial discharge, outputs single-phase sine wave voltage, the frequency adjustment range covers 20-400Hz, the voltage can be steplessly adjusted in the range of 0-500V, and the maximum output current reaches 42.8A, which can meet the diverse frequency and voltage requirements on site. 2. Adjustable resonant compensation inductor unit: It consists of 6 adjustable inductor modules, each with an inductance of 20mH. It is equipped with a multi-tap structure and is connected in parallel with the secondary winding of the current transformer. The capacitive current generated by stray capacitance is offset by finely adjusting the inductance. 3. Multi-parameter monitoring unit: Equipped with high-precision voltage sensor, current sensor and power factor detection module, it collects voltage and current data and power factor value cosΦ of each winding in real time, where Φ is the phase angle of voltage relative to current. The data sampling frequency is not less than 1kHz to ensure measurement accuracy. 4. Intelligent control unit: With a high-performance microcontroller as the core controller, it has a built-in dynamic correction algorithm for the capacity rise effect, closed-loop power factor adjustment logic and step-by-step boost control program. It can adaptively adjust the output parameters according to the monitoring data to ensure the safety and controllability of the test process.

[0022] In this preferred embodiment, each inductor module is configured with a multi-position tap structure, and the inductance of different phase lengths can be adjusted by adjusting the position.

[0023] Embodiment 2 of the present invention proposes a field induced withstand voltage test method for electromagnetic voltage transformers used in GIS based on the system described in Embodiment 1 of the present invention, specifically as follows: Open the GIS busbar isolating switch and reliably ground the tail end of the primary winding of the electromagnetic voltage transformer, the equipment support, the casing and the iron core. Ground the tail ends of all secondary windings of the electromagnetic voltage transformer and keep the head end of the uncompensated winding in a floating state. The uncompensated winding is the secondary winding of the electromagnetic voltage transformer. Adjust the test frequency and voltage amplitude of the variable frequency power supply output, calculate the compensation inductance based on the reading of the secondary winding current of any electromagnetic voltage transformer, and configure the tap position of each inductor module of the adjustable resonant compensation inductor unit so that the total inductance value of all inductor modules reaches the compensation inductance. Keeping the amplitude constant, adjust the output frequency converter voltage of the frequency converter power supply, and detect the power factor of the secondary winding of each electromagnetic voltage transformer. If the power factor is not in the set range, adjust the corresponding inductor module until the power factor is in the set range. Specifically, if cosΦ is in the range of 0.5-0.9, it indicates that the compensation amount is appropriate; if cosΦ is too large, increase the inductance value of the inductor module by 0.5-1Ω; if cosΦ is too small, decrease the inductance value of the inductor module by 0.5-1Ω.

[0024] Adjust the frequency converter to perform a stepped voltage boost. After the stepped voltage boost is completed, the previously set withstand voltage time is used. If the insulation medium of the electromagnetic voltage transformer does not break down within the set withstand voltage time, and the voltage and current waveforms of all windings on the secondary side of the electromagnetic voltage transformer do not change abruptly, and the power factor remains within the set range, then the corresponding electromagnetic voltage transformer is deemed to have passed the induced withstand voltage test; otherwise, it is deemed to be unqualified.

[0025] In this preferred embodiment, the set test frequency is specifically: The set test frequency is between the set first frequency threshold and the third frequency threshold, and the rated frequency is preferred. If core saturation is detected during the process of calculating the compensation inductance based on the read secondary winding current of any electromagnetic voltage transformer, or during the process of setting the tap position of the adjustable resonant compensation inductor unit to make the corresponding inductor module reach the compensation inductance, the frequency is adjusted to between the second frequency threshold and the third frequency threshold. The first frequency is less than or equal to the rated frequency, the second frequency and the third frequency are both greater than or equal to the rated frequency, and the second frequency is less than the third frequency.

[0026] Specifically, in this embodiment, the rated frequency is 150Hz, the first frequency is 120Hz, the second frequency is 200Hz, and the third frequency is 300Hz.

[0027] In this preferred embodiment, the calculation of the compensation inductance based on the read secondary winding current of any electromagnetic voltage transformer specifically involves: The amplitude is set to the rated voltage, specifically 100V in this embodiment. The input capacitive reactance is obtained by dividing the rated voltage by the product of the ratio of the secondary winding current of the corresponding electromagnetic voltage transformer to the number of turns on the primary and secondary sides. Input capacitive reactance value The formula is:

[0028] in, To set the amplitude, This refers to the secondary winding current of the corresponding electromagnetic voltage transformer. The secondary winding includes auxiliary windings and non-auxiliary windings. The current detected in the auxiliary windings and non-auxiliary windings are different, resulting in different input capacitive reactance values, target capacitive reactance values, and compensation inductance values. The ratio of the number of turns on the primary side to the number of turns on the secondary side is given in this embodiment. .

[0029] Different capacitance increase factors are set for different voltage levels to obtain the capacitance increase factor corresponding to the voltage level of the electromagnetic voltage transformer; Multiply the input capacitive reactance value by the capacitive rise factor corresponding to the electromagnetic voltage transformer to obtain the target inductive reactance value, and divide the target inductive reactance value by 2π and then by the set test frequency to obtain the compensation inductance. The formula is:

[0030] in, The target's resistance value; The capacity factor is 1.25 in this embodiment; The set test frequency; To compensate for the inductance.

[0031] In this preferred embodiment, the stepped voltage boost specifically refers to... like Figure 2 As shown, the first stage: apply voltage to the ratio of the system's highest voltage Um to √3, and continue for the first set period; Second stage: The second cycle involves boosting the voltage to the system's highest voltage Um and maintaining the system's highest voltage Um continuously. Third stage: Increase the voltage to the withstand voltage value U f and maintain the withstand voltage value U f The third cycle is continuously set, and the third cycle is calculated as 120 multiplied by the rated frequency f. n With test frequency f S If the product of the two values ​​is not less than the set time threshold, then the product of the two values ​​is used as the third cycle; otherwise, the set time threshold is used as the third cycle.

[0032] During the stepped voltage boost process, if the current of any electromagnetic voltage transformer secondary winding monitored in real time by the intelligent control unit exceeds the set secondary winding current, or if the voltage of any electromagnetic voltage transformer secondary auxiliary winding or any electromagnetic voltage transformer secondary winding (specifically, in this embodiment, the voltage of winding 3a3n is measured) shows a voltage surge or resonance characteristic signal, the voltage boost is paused and the inductance of each inductor module is adjusted until the current of each electromagnetic voltage transformer secondary winding does not exceed the set secondary winding current. Once the voltage of the electromagnetic voltage transformer secondary auxiliary winding or any electromagnetic voltage transformer secondary winding has not shown a voltage surge or resonance characteristic signal, the stepped voltage boost continues.

[0033] In this preferred embodiment, the occurrence of voltage sudden change or resonance characteristic signal specifically refers to: If the absolute value of the rate of change of the voltage amplitude compared to the voltage amplitude at the previous moment exceeds a set threshold, or if the total harmonic distortion rate calculated after performing a Fourier transform of the voltage signal or the set subharmonic content rate exceeds a set threshold, then a voltage sudden change or resonance characteristic signal is determined to have occurred.

[0034] This embodiment uses a 220kV GIS electromagnetic voltage transformer (model JDQXF3-220) in a 220kV substation in Liaoyang as an example to perform the above steps. The core parameters of JDQXF3-220 are as follows: Rated primary voltage: 220 / √3kV; Rated insulation level: 252 / 460 / 1050kV; Rated frequency: 50Hz; Rated voltage ratio: 220 / √3 / 0.1 / √3 / 0.1 / √3 / 0.1 / √3 / 0.1kV; Maximum permissible secondary current: 40A (1min) In this embodiment, after applying a 150Hz, 100V voltage, the secondary winding current was measured to be i. udxd =0.87A, calculate X C =100 / (0.87×√3)≈66.3Ω,X L =66.3×1.25≈82.9Ω, L=82.9 / (2×π×150)≈88.7mH (actual configuration: 2.26mH auxiliary winding compensation inductor, 1.87mH non-auxiliary winding compensation inductor); the measured cosΦ=0.72, which meets the requirements; For the secondary auxiliary winding of the electromagnetic voltage transformer (i.e. Figure 1 The voltage of the secondary windings in this embodiment is increased by 106V / 5min → 184V / 3min → 268V / 20s (capacitance increase of 8%) after the turns ratio is calculated. During the process, the maximum current on the secondary side is 32A, which does not exceed 40A. The voltage and current waveforms are stable, and cosΦ is maintained between 0.68 and 0.75. The final test result showed that the transformer insulation did not break down during the 268V / 20s withstand voltage test, and all parameters were normal. The test was therefore deemed passed.

[0035] This embodiment verifies the feasibility and reliability of the present invention, and is applicable to the field induced withstand voltage test of electromagnetic voltage transformers for GIS with voltage levels of 220kV and similar.

[0036] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0037] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0038] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0039] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A field induced withstand voltage test system for electromagnetic voltage transformers used in GIS, comprising a frequency converter power supply unit, an adjustable resonant compensation inductor unit, a multi-parameter monitoring unit, and an intelligent control unit, characterized in that: The secondary winding of an electromagnetic voltage transformer includes an auxiliary winding and several non-auxiliary windings. The frequency converter power supply unit is connected to the secondary auxiliary winding of the electromagnetic voltage transformer to output a continuously adjustable sinusoidal voltage. The adjustable resonant compensation inductor unit includes multiple inductor modules, each inductor module being connected in parallel with the secondary winding of an electromagnetic voltage transformer, and the inductance of each inductor module is adjustable; The multi-parameter monitoring unit includes multiple voltage sensing modules, current sensing modules, and power factor detection modules, which respectively collect the effective voltage value, effective current value, and power factor data of each secondary winding in real time. The intelligent control unit is communicatively connected to the frequency converter, the adjustable resonant compensation inductor, and the multi-parameter monitoring unit, respectively, and is used to dynamically adjust the output frequency of the frequency converter and the inductance of the adjustable resonant compensation inductor based on the data monitored by the multi-parameter monitoring unit.

2. The on-site inductive withstand voltage test system for electromagnetic voltage transformers used in GIS according to claim 1, characterized in that: Each inductor module is equipped with a multi-position tap structure, which allows for adjustment of the inductance of different lengths by adjusting the position.

3. A method for on-site induced withstand voltage testing of an electromagnetic voltage transformer for GIS based on the system described in claim 2, characterized in that: Open the GIS busbar isolating switch and reliably ground the tail end of the primary winding of the electromagnetic voltage transformer, the equipment support, the casing and the iron core. Ground the tail ends of all secondary windings of the electromagnetic voltage transformer and keep the head end of the uncompensated winding in a floating state. The uncompensated winding is the secondary winding of the electromagnetic voltage transformer. Adjust the test frequency and voltage amplitude of the variable frequency power supply output, calculate the compensation inductance based on the reading of the secondary winding current of any electromagnetic voltage transformer, and configure the tap position of each inductor module in the adjustable resonant compensation inductor unit so that the total inductance value of all inductor modules reaches the compensation inductance. Keeping the amplitude constant, adjust the output frequency converter voltage of the frequency converter power supply, and detect the power factor of the secondary winding of each electromagnetic voltage transformer. If the power factor is not in the set range, adjust the corresponding inductor module until the power factor is in the set range. Adjust the frequency converter to perform a stepped voltage boost. After the stepped voltage boost is completed, the previously set withstand voltage time is used. If the insulation medium of the electromagnetic voltage transformer does not break down within the set withstand voltage time, and the voltage and current waveforms of all windings on the secondary side of the electromagnetic voltage transformer do not change abruptly, and the power factor remains within the set range, then the corresponding electromagnetic voltage transformer is deemed to have passed the induced withstand voltage test; otherwise, it is deemed to be unqualified.

4. The method for on-site induced withstand voltage testing of an electromagnetic voltage transformer for GIS according to claim 3, characterized in that: The set test frequency is specifically as follows: If, during the process of calculating the compensation inductance based on the secondary winding current of any electromagnetic voltage transformer, or during the process of configuring the tap position of the adjustable resonant compensation inductor unit to make the corresponding inductor module reach the compensation inductance, core saturation is detected, the frequency is adjusted to be between the second and third frequency thresholds. The first frequency is less than or equal to the rated frequency, the second and third frequencies are both greater than or equal to the rated frequency, and the second frequency is less than the third frequency.

5. The method for on-site induced withstand voltage testing of an electromagnetic voltage transformer for GIS according to claim 4, characterized in that: The calculation of the compensation inductance based on the read secondary winding current of any electromagnetic voltage transformer is specifically as follows: The amplitude is set to the rated voltage. The input capacitive reactance value is obtained by dividing the rated voltage by the product of the ratio of the secondary winding current of the corresponding electromagnetic voltage transformer to the number of turns on the primary and secondary sides. Different capacitance increase factors are set for different voltage levels to obtain the capacitance increase factor corresponding to the voltage level of the electromagnetic voltage transformer; The target inductive reactance is obtained by multiplying the input capacitive reactance value by the capacitive rise factor corresponding to the electromagnetic voltage transformer. The target inductive reactance value is then divided by 2π and then by the set test frequency to obtain the compensation inductance.

6. The method for on-site induced withstand voltage testing of an electromagnetic voltage transformer for GIS according to claim 3, characterized in that: The stepped voltage boost is specifically as follows: Phase 1: Apply voltage to the ratio of the system's highest voltage Um to √3, and continue for the first set period; Second stage: The second cycle of boosting the voltage to the highest system voltage Um and maintaining the highest system voltage Um continuously. Third stage: Increase the voltage to the withstand voltage value U f and maintain the withstand voltage value U f The third cycle is continuously set, and the third cycle is calculated as 120 multiplied by the rated frequency f. n With test frequency f S If the product of the two values ​​is not less than the set time threshold, then the product of the two values ​​is used as the third cycle; otherwise, the set time threshold is used as the third cycle.

7. The method for on-site induced withstand voltage testing of an electromagnetic voltage transformer for GIS according to claim 3, characterized in that: During the stepped voltage boost process, if the current of any electromagnetic voltage transformer's secondary winding exceeds the set current that the secondary winding can withstand, or if the voltage of any electromagnetic voltage transformer's secondary auxiliary winding or any winding on the secondary side shows a voltage surge or resonance characteristic signal, the voltage boost will be paused and the inductance of each inductor module will be adjusted until the current of each electromagnetic voltage transformer's secondary winding does not exceed the set current that the secondary winding can withstand. Once the voltage of any electromagnetic voltage transformer's secondary auxiliary winding or any winding on the secondary side has stopped showing a voltage surge or resonance characteristic signal, the stepped voltage boost will continue.

8. The method for on-site induced withstand voltage testing of an electromagnetic voltage transformer for GIS according to claim 7, characterized in that: The occurrence of voltage abrupt changes or resonance characteristic signals specifically refers to: If the absolute value of the rate of change of the voltage amplitude compared to the voltage amplitude at the previous moment exceeds a set threshold, or if the total harmonic distortion rate calculated after performing a Fourier transform of the voltage signal or the set subharmonic content rate exceeds a set threshold, then a voltage sudden change or resonance characteristic signal is determined to have occurred.

9. An apparatus comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor performing the steps of the field induced withstand voltage test method for electromagnetic voltage transformers for GIS according to any one of claims 3-8.

10. A computer-readable storage medium storing a computer program that, when executed by a processor, uses the steps of the on-site induced withstand voltage test method for electromagnetic voltage transformers for GIS according to any one of claims 3-8.

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