System and method for detecting accuracy of bushing end screen current sensor

Abstract

The invention discloses a system and method for detecting the accuracy of a bushing end screen current sensor, and belongs to the technical field of sensor performance detection. The system comprises a test loop and a power frequency magnetic field generator, the test loop comprises a multifunctional electrical measuring instrument calibrating device, a standard digital multimeter and a terminal acquisition and display device, and a bushing end screen current sensor to be tested is connected in series between the standard digital multimeter and the terminal acquisition and display device. And determining the accuracy of the bushing end screen current sensor to be detected according to the amplitude and the phase angle difference of the equivalent current. According to the invention, power frequency magnetic field interference suffered by the bushing end screen current sensor can be simulated, and the accuracy of the sensor under the power frequency magnetic field interference can be accurately measured.

Description

Technical Field

[0001] The present invention relates to the technical field of sensor performance detection, and more specifically, to a system and method for detecting the accuracy of a bushing end screen current sensor. Background Art

[0002] As an important component of AC and DC power transmission systems, bushings play the role of insulation, conductive connection and support, and are the only way for electric energy transmission. With the continuous development of my country's ultra-high voltage transmission technology, the transmission capacity and voltage level have increased, and bushings carry higher voltages, larger currents and mechanical loads. The electrical, thermal, mechanical and other performance requirements are more stringent, and they are more prone to problems such as electric field concentration, conductor overheating, and mechanical damage. Bushing failures can cause the bushing to be damaged at the least, or even explode, damage the transformer, and cause power outages in the power grid, seriously affecting the safe operation of the power grid, causing economic losses and social impacts. At present, online bushing monitoring devices are often used to accurately sense the key parameters of the bushing in real time, and to issue fault warnings to ensure the safe and stable operation of the bushing.

[0003] The bushing end screen current is a key parameter for bushing online monitoring. The key parameters of bushing insulation status such as bushing dielectric loss factor, capacitance, partial discharge, etc. can be obtained through appropriate analysis methods. Therefore, it is necessary to ensure the accuracy and reliability of the bushing end screen current measurement results.

[0004] The bushing end screen current is generally measured using a non-contact electromagnetic induction element. This type of sensor is easily interfered by the power frequency magnetic field. According to research results, compared with the measurement results when the load current in the high-voltage bushing conductive rod is 0 (no power frequency magnetic field interference), when the load current in the high-voltage bushing conductive rod is 1600A, the maximum phase error of the measurement result is 11°, and the maximum amplitude error is +78%. Therefore, when selecting the bushing end screen current sensor, it is necessary to carry out its accuracy test experiment under power frequency magnetic field interference, but there is currently no solution for the accuracy test of the bushing end screen current sensor under magnetic field interference. Summary of the invention

[0005] In view of the above problems, the present invention proposes a system for detecting the accuracy of a bushing end screen current sensor, comprising:

[0006] Test circuit and power frequency magnetic field generator;

[0007] The test circuit includes: a multifunctional electric measuring instrument calibration device, a standard digital multimeter and a terminal acquisition and display device, wherein the standard digital multimeter and the terminal acquisition and display device are connected in series with the bushing end screen current sensor to be tested;

[0008] The power frequency magnetic field generator is used to generate a preset power frequency magnetic field interference, the multifunctional electrical measuring instrument calibration device is used to output a reference voltage signal and different standard test signals, the standard digital multimeter is used to measure the standard test signal and transmit the standard test signal to the bushing end screen current sensor to be tested, the terminal acquisition and display device is used to record the amplitude and phase angle before and after the power frequency magnetic field interference and under different standard test signals, the measurement result of the standard digital multimeter is used as the reference of the current amplitude, the phase angle difference between the reference voltage signal output by the multifunctional electrical measuring instrument calibration device and the standard current signal is used as the current phase reference, and compared with the amplitude and phase angle to obtain the amplitude and phase angle difference of the equivalent current, and the accuracy of the bushing end screen current sensor to be tested is determined according to the amplitude and phase angle difference of the equivalent current.

[0009] Optionally, a multifunctional electrical measuring instrument calibration device, a standard digital multimeter and a terminal acquisition and display device are connected in series to form a test circuit.

[0010] Optionally, the multifunctional electrical measuring instrument calibration device outputs a phase as a current phase reference.

[0011] Optionally, the power frequency magnetic field generator generates a preset power frequency magnetic field interference of 1 mT.

[0012] Optional, different standard test signals, including:

[0013] The standard test signal with a voltage amplitude of 5V, a current of 0-200mA and a phase angle difference of 0° is used to measure the amplitude of the equivalent current generated by the current sensor at the end screen of the bushing to be tested;

[0014] The standard test signal with a voltage amplitude of 5V, a current of 0mA and a phase angle difference of 0-80° is used to measure the phase angle difference generated by the current sensor at the end screen of the bushing to be tested.

[0015] Optionally, before the power frequency magnetic field interference, the amplitude and phase angle difference of the equivalent current generated under the standard test signal with a voltage amplitude of 5V, a current of 0mA, and a phase angle difference of 0° are recorded.

[0016] Optionally, after the power frequency magnetic field interference, the amplitude of the equivalent current generated under the standard test signal with a voltage amplitude of 5V, a current of 0-200mA, and a phase angle difference of 0° is recorded.

[0017] Optionally, after the power frequency magnetic field interference, the phase angle difference generated under the standard test signal with a voltage amplitude of 5V, a current of 0mA, and a phase angle difference of 0-80° is recorded.

[0018] Optionally, determine the accuracy of the bushing end screen current sensor to be tested, including:

[0019] Determine the changes in the amplitude and phase angle difference of the equivalent current, and judge whether the changes meet the preset conditions. If so, determine that the current sensor of the end screen of the bushing to be tested has accuracy under the interference of the power frequency magnetic field.

[0020] Optionally, if the absolute value of the change in the amplitude of the equivalent current is less than 100 μA and the absolute value of the change in the phase angle difference is less than 0.1°, the preset condition is met.

[0021] On the other hand, the present invention also provides a method for detecting the accuracy of a bushing end screen current sensor, comprising:

[0022] The power frequency magnetic field generator is used for preset power frequency magnetic field interference;

[0023] Output reference voltage signals and different standard test signals through the multifunctional electrical measuring instrument verification device;

[0024] Measuring the standard test signal by a standard digital multimeter, and transmitting the standard test signal to the end screen current sensor of the bushing to be tested;

[0025] The terminal acquisition and display device records the current before and after the power frequency magnetic field interference and under different standard test signals. The measurement results of the standard digital multimeter are used as the reference of the current amplitude, and the phase angle difference between the reference voltage signal output by the multi-function electrical measuring instrument calibration device and the standard current signal is used as the current phase reference. According to the amplitude and phase angle difference of the equivalent current, the accuracy of the current sensor at the end screen of the bushing to be tested is determined.

[0026] In yet another aspect, the present invention further provides a computing device, comprising: one or more processors;

[0027] a processor for executing one or more programs;

[0028] When the one or more programs are executed by the one or more processors, the above-described method is implemented.

[0029] In yet another aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed, the method described above is implemented.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention provides a system for detecting the accuracy of a bushing end screen current sensor, comprising: a test circuit and a power frequency magnetic field generator; the test circuit comprises: a multifunctional electric measuring instrument calibration device, a standard digital multimeter and a terminal acquisition and display device, the bushing end screen current sensor to be tested is connected in series between the standard digital multimeter and the terminal acquisition and display device; the power frequency magnetic field generator is used to generate a preset power frequency magnetic field interference, the multifunctional electric measuring instrument calibration device is used to output a reference voltage signal and different standard test signals, and the standard digital multimeter is used to perform a voltage test on the standard test signal. The terminal acquisition and display device is used to record the amplitude and phase angle before and after the power frequency magnetic field interference and under different standard test signals, and the measurement result of the standard digital multimeter is used as the reference of the current amplitude, and the phase angle difference between the reference voltage signal output by the multifunctional electrical measuring instrument calibration device and the standard current signal is used as the current phase reference, and compared with the amplitude and phase angle, the amplitude and phase angle of the equivalent current are obtained, and the accuracy of the current sensor of the end screen of the bushing to be tested is determined according to the amplitude and phase angle difference of the equivalent current. The present invention can simulate the power frequency magnetic field interference of the bushing end screen current sensor, and can accurately measure the accuracy of the sensor under the power frequency magnetic field interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a structural diagram of the system of the present invention;

[0033] Figure 2 Schematic diagram of the implementation principle of the system of the present invention. DETAILED DESCRIPTION

[0034] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0035] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0036] Embodiment 1:

[0037] The present invention proposes a system for detecting the accuracy of a bushing end screen current sensor. Figure 1As shown, including:

[0038] Test circuit and power frequency magnetic field generator;

[0039] The test circuit includes: a multifunctional electric measuring instrument calibration device, a standard digital multimeter and a terminal acquisition and display device, wherein the standard digital multimeter and the terminal acquisition and display device are connected in series with the bushing end screen current sensor to be tested;

[0040] The power frequency magnetic field generator is used to generate a preset power frequency magnetic field interference, the multifunctional electrical measuring instrument calibration device is used to output a reference voltage signal and different standard test signals, the standard digital multimeter is used to measure the standard test signal and transmit the standard test signal to the bushing end screen current sensor to be tested, the terminal acquisition and display device is used to record the amplitude and phase angle before and after the power frequency magnetic field interference and under different standard test signals, the measurement result of the standard digital multimeter is used as the reference of the current amplitude, the phase angle difference between the reference voltage signal output by the multifunctional electrical measuring instrument calibration device and the standard current signal is used as the current phase reference, and compared with the amplitude and phase angle to obtain the amplitude and phase angle difference of the equivalent current, and the accuracy of the bushing end screen current sensor to be tested is determined according to the amplitude and phase angle difference of the equivalent current.

[0041] Among them, the multifunctional electrical measuring instrument calibration device, the standard digital multimeter and the terminal acquisition and display equipment are connected in series to form a test circuit.

[0042] Among them, the multifunctional electrical measuring instrument calibration device outputs the phase as the current phase reference.

[0043] The power frequency magnetic field generator generates a preset power frequency magnetic field interference of 1 mT.

[0044] Among them, different standard test signals include:

[0045] The standard test signal with a voltage amplitude of 5V, a current of 0-200mA and a phase angle difference of 0° is used to measure the amplitude of the equivalent current generated by the current sensor at the end screen of the bushing to be tested;

[0046] The standard test signal with a voltage amplitude of 5V, a current of 0mA and a phase angle difference of 0-80° is used to measure the phase angle difference generated by the current sensor at the end screen of the bushing to be tested.

[0047] Among them, before the power frequency magnetic field interference, the amplitude and phase difference of the equivalent current generated under the standard test signal with a voltage amplitude of 5V, a current of 0mA, and a phase difference of 0° were recorded.

[0048] Among them, after the power frequency magnetic field interference, the amplitude of the equivalent current generated under the standard test signal with a voltage amplitude of 5V, a current of 0-200mA, and a phase angle difference of 0° is recorded.

[0049] Among them, after the power frequency magnetic field interference, the phase angle difference generated under the standard test signal with a voltage amplitude of 5V, a current of 0mA, and a phase angle difference of 0-80° is recorded.

[0050] Among them, determining the accuracy of the current sensor at the end screen of the bushing to be tested includes:

[0051] Determine the changes in the amplitude and phase angle difference of the equivalent current, and judge whether the changes meet the preset conditions. If so, determine that the current sensor of the end screen of the bushing to be tested has accuracy under the interference of the power frequency magnetic field.

[0052] If the absolute value of the change in the amplitude of the equivalent current is less than 100 μA and the absolute value of the change in the phase angle difference is less than 0.1°, the preset condition is met.

[0053] The present invention is described below in conjunction with specific cases:

[0054] The system connection diagram is as follows: Figure 1 As shown in the figure, the system consists of a power frequency magnetic field generator, a multifunctional electrical measuring instrument calibration device, a standard digital multimeter, and a terminal acquisition and display device. The power frequency magnetic field generator can provide the required power frequency magnetic field interference, the standard digital multimeter is connected in series in the circuit, and its measurement result is used as the reference of the current amplitude, the multifunctional electrical measuring instrument calibration device provides the reference voltage signal and standard current signal required for the experiment, and its output phase is used as the current phase reference, and the terminal acquisition and display device can collect and display the measurement results of the bushing end screen current sensor.

[0055] The principle of the detection method is: using the multifunctional electrical measuring instrument calibration device to output voltage and current signals, taking the displayed phase angle as the reference, and taking the current amplitude displayed by the standard digital multimeter in series in the circuit as the reference, the current amplitude and phase angle obtained by the bushing end screen current sensor before and after the magnetic field with a power frequency magnetic induction intensity of 1mT are compared, and the amplitude and phase angle difference change of the equivalent current generated by the magnetic field with a power frequency magnetic induction intensity of 1mT on the bushing end screen current sensor are obtained. The calculation formulas of the amplitude and phase angle difference change of the equivalent current are shown in formulas 1 and 2 respectively. If the absolute value of the amplitude of the equivalent current is less than 100μA and the absolute value of the phase angle difference change is less than 0.1°, it can be considered that the bushing end screen current sensor has good measurement accuracy under the interference of the power frequency magnetic field.

[0056] I m =I2-I1 (Formula 1)

[0057] Δθ=θ2-θ1 (Formula 2)

[0058] Where: I mis the equivalent current amplitude, I2 is the current amplitude measured after the action of the magnetic field with the industrial frequency magnetic induction intensity of 1mT, I1 is the current amplitude measured without the action of the magnetic field, Δθ is the change in the phase angle difference, θ2 is the phase angle difference measured after the action of the magnetic field with the industrial frequency magnetic induction intensity of 1mT, and θ1 is the phase angle difference measured without the action of the magnetic field.

[0059] The detection method flow of the system of the present invention is as follows Figure 2 As shown, including:

[0060] 1. Test steps for amplitude measurement accuracy:

[0061] (a) Arrange the bushing end screen current sensor, multi-function electric measuring instrument calibration device, power frequency magnetic field generating device, standard digital multimeter and terminal acquisition and display equipment.

[0062] (b) Use the multifunctional electrical measuring instrument calibration device to generate an output with a voltage amplitude of 5V, a current of 0mA, and a phase angle difference of 0°, and record the amplitude of the leakage current obtained by the bushing end screen current sensor.

[0063] (c) After the amplitude of the leakage current obtained by the bushing end screen current sensor becomes stable, a power frequency magnetic field generating device is used to generate a magnetic field with a power frequency magnetic induction intensity of 1 mT, and the amplitude of the leakage current obtained by the bushing end screen current sensor is recorded.

[0064] (d) Based on the amplitude of the leakage current obtained by the bushing end screen current sensor device obtained in (b) and (c), the two are subtracted to obtain the amplitude of the equivalent current generated by the bushing end screen current sensor when the test current is 0mA and the magnetic field with an industrial frequency magnetic induction intensity of 1mT.

[0065] (e) Ensure that the voltage and phase angle difference generated by the functional electrical measuring instrument calibration device remain unchanged, change the output current to 50mA, 100mA, 150mA, and 200mA, and repeat steps (b), (c), and (d) to obtain the amplitude of the equivalent current generated by the magnetic field with an industrial frequency magnetic induction intensity of 1mT on the bushing end screen current sensor under different current conditions.

[0066] 2. Test steps for phase angle measurement accuracy:

[0067] (a) Arrange the bushing end screen current sensor, multi-function electric measuring instrument calibration device, power frequency magnetic field generating device, standard digital multimeter and terminal acquisition and display equipment.

[0068] (b) Use the multifunctional electrical measuring instrument calibration device to generate an output with a voltage amplitude of 5 V, a current of 150 mA, and a phase angle difference of 0°, and record the phase angle difference obtained by the bushing end screen current sensor.

[0069] (c) After the phase angle difference obtained by the bushing end screen current sensor is stable, a power frequency magnetic field generator is used to generate a magnetic field with a power frequency magnetic induction intensity of 1 mT, and the phase angle difference obtained by the bushing end screen current sensor is recorded.

[0070] (d) The phase angle difference of the bushing end screen current sensor obtained according to (b) and (c) is subtracted from each other to obtain the phase angle difference of the bushing end screen current sensor generated by the magnetic field with an industrial frequency magnetic induction intensity of 1mT when the output phase angle difference is 0°.

[0071] (e) Keep the voltage and phase angle difference generated by the functional electrical measuring instrument calibration device unchanged, change the output phase angle difference to 10°, 20°, 40°, and 80°, and repeat steps (b), (c), and (d) to obtain the phase angle difference generated by the magnetic field with an industrial frequency magnetic induction intensity of 1 mT on the bushing end screen current sensor under different phase angle difference conditions.

[0072] 3. Determination of measurement accuracy:

[0073] If the absolute value of the amplitude of the equivalent current of all measurement results is less than 100 μA and the absolute value of the phase angle difference change is less than 0.1°, it can be considered that the bushing end screen current sensor has good measurement accuracy under power frequency magnetic field interference.

[0074] The invention can simulate the power frequency magnetic field interference to the bushing end screen current sensor and proposes a basis for determining the accuracy result.

[0075] Embodiment 2:

[0076] The present invention also proposes a method for detecting the accuracy of a bushing end screen current sensor, comprising:

[0077] Step 1, using a power frequency magnetic field generator for preset power frequency magnetic field interference;

[0078] Step 2: Output reference voltage signals and different standard test signals through the multifunctional electrical measuring instrument verification device;

[0079] Step 3, measuring the standard test signal by a standard digital multimeter, and transmitting the standard test signal to the end screen current sensor of the bushing to be tested;

[0080] Step 4: Record the amplitude and phase angle before and after the power frequency magnetic field interference and under different standard test signals through the terminal acquisition and display device, use the measurement result of the standard digital multimeter as the reference of the current amplitude, and the phase angle difference between the reference voltage signal output by the multi-function electrical measuring instrument calibration device and the standard current signal as the current phase reference, compare with the amplitude and phase angle, and obtain the amplitude and phase angle difference of the equivalent current. According to the amplitude and phase angle difference of the equivalent current, determine the accuracy of the current sensor of the end screen of the bushing to be tested.

[0081] Embodiment 3:

[0082] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding functions, so as to implement the steps of the method in the above embodiment.

[0083] Embodiment 4:

[0084] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both a built-in storage medium in a computer device and an extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the method in the above embodiment.

[0085] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The schemes in the embodiments of the present invention may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0086] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0087] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0088] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0089] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0090] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A system for detecting the accuracy of a bushing end screen current sensor, characterized in that: include: Test circuit and power frequency magnetic field generator; The test circuit includes: a multifunctional electric measuring instrument calibration device, a standard digital multimeter and a terminal acquisition and display device, wherein the standard digital multimeter and the terminal acquisition and display device are connected in series with the bushing end screen current sensor to be tested; The power frequency magnetic field generator is used to generate a preset power frequency magnetic field interference, the multifunctional electrical measuring instrument calibration device is used to output a reference voltage signal and different standard test signals, the standard digital multimeter is used to measure the standard test signal and transmit the standard test signal to the bushing end screen current sensor to be tested, the terminal acquisition and display device is used to record the amplitude and phase angle before and after the power frequency magnetic field interference and under different standard test signals, the measurement result of the standard digital multimeter is used as the reference of the current amplitude, the phase angle difference between the reference voltage signal output by the multifunctional electrical measuring instrument calibration device and the standard current signal is used as the current phase reference, and compared with the amplitude and phase angle to obtain the amplitude and phase angle difference of the equivalent current, and the accuracy of the bushing end screen current sensor to be tested is determined according to the amplitude and phase angle difference of the equivalent current.

2. The system according to claim 1, characterized in that The multifunctional electrical measuring instrument calibration device, the standard digital multimeter and the terminal acquisition and display device are sequentially connected in series to form a test circuit.

3. The system according to claim 1, characterized in that The multifunctional electric measuring instrument verification device outputs a phase as a current phase reference.

4. The system according to claim 1, characterized in that The power frequency magnetic field generator generates a preset power frequency magnetic field interference of 1 mT.

5. The system according to claim 1, characterized in that The different standard test signals include: The standard test signal with a voltage amplitude of 5V, a current of 0-200mA and a phase angle difference of 0° is used to measure the amplitude of the equivalent current generated by the current sensor at the end screen of the bushing to be tested; The standard test signal with a voltage amplitude of 5V, a current of 0mA and a phase angle difference of 0-80° is used to measure the phase angle difference generated by the current sensor at the end screen of the bushing to be tested.

6. The system according to claim 1, characterized in that Before the power frequency magnetic field interference, record the amplitude and phase difference of the equivalent current generated under the standard test signal with a voltage amplitude of 5V, a current of 0mA, and a phase difference of 0°.

7. The system according to claim 1, characterized in that After the power frequency magnetic field interference, record the amplitude of the equivalent current generated under the standard test signal with a voltage amplitude of 5V, a current of 0-200mA, and a phase angle difference of 0°.

8. The system according to claim 1, characterized in that After the power frequency magnetic field interference, the phase angle difference generated under the standard test signal with a voltage amplitude of 5V, a current of 0mA, and a phase angle difference of 0-80° is recorded.

9. The system according to claim 1, characterized in that The step of determining the accuracy of the current sensor of the end screen of the bushing to be tested comprises: Determine the changes in the amplitude and phase angle difference of the equivalent current, and judge whether the changes meet the preset conditions. If so, determine that the current sensor of the end screen of the bushing to be tested has accuracy under the interference of the power frequency magnetic field.

10. The system according to claim 9, characterized in that If the absolute value of the change in the amplitude of the equivalent current is less than 100 μA and the absolute value of the change in the phase angle difference is less than 0.1°, the preset condition is met.

11. A method for detecting the accuracy of a bushing end shield current sensor using a system for detecting the accuracy of a bushing end shield current sensor according to any one of claims 1 to 10, characterized in that: include: The power frequency magnetic field generator is used for preset power frequency magnetic field interference; Output reference voltage signals and different standard test signals through the multifunctional electrical measuring instrument verification device; Measuring the standard test signal by a standard digital multimeter, and transmitting the standard test signal to the end screen current sensor of the bushing to be tested; The amplitude and phase angle before and after the power frequency magnetic field interference and under different standard test signals are recorded by the terminal acquisition and display device. The measurement result of the standard digital multimeter is used as the reference of the current amplitude, and the phase angle difference between the reference voltage signal output by the multi-function electrical measuring instrument calibration device and the standard current signal is used as the current phase reference. The amplitude and phase angle are compared with each other to obtain the amplitude and phase angle difference of the equivalent current. According to the amplitude and phase angle difference of the equivalent current, the accuracy of the current sensor at the end screen of the bushing to be tested is determined.

12. A computer device, characterized in that: include: one or more processors; a processor for executing one or more programs; When the one or more programs are executed by the one or more processors, the method according to claim 11 is implemented.

13. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the method according to claim 11 is implemented.

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