Direct-current partial discharge detection device and method based on X-ray excitation

Abstract

The invention discloses a direct current partial discharge detection device and method based on X-ray excitation. The device comprises an experiment test board, a pressurization module, a detection processing module and an X-ray source. The pressurization module is used for carrying out a plurality of pressurization tests on the tested product; the detection processing module is used for judging whether the partial discharge phenomenon of the tested product is detected in the process of each pressurization test; if the partial discharge phenomenon is detected, determining that the tested product has an insulation defect; if the partial discharge phenomenon is not detected, receiving an electrical signal generated by the tested product after the X-ray source emits quantitative X-ray pulse, judging that the tested product has an insulation defect when determining that the tested product has the partial discharge phenomenon, and judging that the tested product has an insulation defect when determining that the tested product does not have the partial discharge phenomenon. And according to a preset step voltage, increasing the voltage value in the pressurization test by one step. According to the invention, the problem that the DC partial discharge signal is difficult to extract in the insulation detection of the power equipment can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of insulation detection of electric power equipment, and in particular to a direct current partial discharge detection device and method based on X-ray excitation. Background Art

[0002] Partial discharge refers to discharge that occurs between electrodes but does not penetrate the electrodes. It is caused by weaknesses in the insulation of the equipment or defects caused during the production process, and repeated breakdown and extinguishing occurs under high electric field strength. In high-voltage DC equipment, the detection and analysis of partial discharge is crucial to ensure the safe operation of the equipment. Partial discharge not only affects the insulation performance of the equipment, but may also cause serious failure or damage to the equipment. Therefore, in the power system, accurate detection and monitoring of partial discharge is of great significance.

[0003] Since there are many factors inducing partial discharge during the online operation and maintenance of DC power equipment, the uncertainty is significantly increased compared to traditional AC power transmission. The application of traditional AC partial discharge detection and identification methods is limited. In particular, DC partial discharge signals usually have a small amplitude and a wide frequency range, and are easily affected by external electromagnetic interference, which makes signal extraction difficult. Summary of the invention

[0004] The embodiment of the present invention provides a DC partial discharge detection device and method based on X-ray excitation. By implementing the present invention, the method based on X-ray excitation can be used to detect partial discharge of high-voltage DC equipment, thereby solving the problem of difficulty in extracting DC partial discharge signals of power equipment.

[0005] An embodiment of the present invention provides a DC partial discharge detection device based on X-ray excitation, including an experimental test bench, a pressurization module, a detection processing module and an X-ray source:

[0006] The experimental test bench is used to place the tested product.

[0007] The pressure module is used to perform several pressure tests on the tested product until insulation defects are detected in the tested product or the voltage value corresponding to the current pressure test is the maximum voltage value that the tested product can withstand; wherein the voltage value corresponding to the initial pressure test is the smallest voltage value in the preset step voltage.

[0008] The detection and processing module is used to determine whether partial discharge is detected in the tested product during each pressure test; if partial discharge is detected, it is determined that the tested product has insulation defects; if no partial discharge is detected, it is used to receive the electrical signal generated by the tested product after the X-ray source emits a quantitative X-ray pulse, and when it is determined that the tested product has partial discharge according to the electrical signal, it is determined that the tested product has insulation defects, and when it is determined that the tested product does not have partial discharge according to the electrical signal, the voltage value of the pressure module during the pressure test is increased by one step according to a preset step voltage as the updated voltage value.

[0009] Furthermore, the DC partial discharge detection device based on X-ray excitation also includes a signal preprocessing module:

[0010] The signal preprocessing module is used to perform noise suppression, filtering and amplitude adjustment on the electrical signal generated by the tested product during the detection process, and transmit the processed electrical signal to the detection processing module.

[0011] Furthermore, the pressurization module includes a withstand voltage test box, an experimental transformer, a rectifier silicon stack and a protective resistor: the grounding end of the withstand voltage test box is grounded, and the output end of the withstand voltage test box is connected to the input end of the experimental transformer.

[0012] The output end of the experimental transformer is connected to the input end of the rectifier silicon stack.

[0013] The output end of the rectifier silicon stack is connected to the input end of the protection resistor.

[0014] The output end of the protection resistor is connected to the signal preprocessing module.

[0015] Furthermore, the signal preprocessing module includes a current limiting resistor, a coupling capacitor, a filter capacitor and a voltage divider: the output end of the protection resistor is connected to the input end of the current limiting resistor.

[0016] The input end of the current limiting resistor is also connected to the input end of the filter capacitor.

[0017] The output end of the current limiting resistor is connected to the input end of the coupling capacitor.

[0018] The input terminal of the coupling capacitor is also connected to the input terminal of the voltage divider.

[0019] The output end of the coupling capacitor is connected to the input end of the experimental test bench.

[0020] The ground terminal of the coupling capacitor and the output terminal of the voltage divider are connected to the detection processing module.

[0021] The output terminal of the filter capacitor is grounded.

[0022] The output terminal of the experimental test bench is grounded.

[0023] Furthermore, the detection processing module includes an oscilloscope, a multi-device control unit, a data acquisition unit, an external detection impedance and a computer: the ground terminal of the coupling capacitor is connected to the input terminal of the oscilloscope.

[0024] The input terminal of the oscilloscope is also connected to the AC terminal of the data acquisition unit.

[0025] The output end of the voltage divider is connected to the input end of the external detection impedance IN.

[0026] The PD end of the external detection impedance is connected to the BNC end of the data acquisition unit.

[0027] The ground terminal of the external sense impedance is connected to ground.

[0028] The LC terminal of the data acquisition unit is connected to the input terminal of the multi-device control unit.

[0029] The output terminal of the multi-device control unit is connected to the input terminal of the computer.

[0030] Furthermore, the detection threshold of partial discharge is set to 10 pC.

[0031] Furthermore, the voltage value step difference of the preset step voltage is positively correlated with the size of the tested product.

[0032] Furthermore, the X-ray source is an XR 270kV pulse light source; wherein the distance between the exit port of the X-ray source and the tested object is 20cm, and the energy of each X-ray pulse is 1μSv.

[0033] Furthermore, the oscilloscope is a Teledyne high-speed oscilloscope WafeSurfer510, with a bandwidth of 1 GHz and a maximum sampling rate of 10 GS / s.

[0034] An embodiment of the present invention provides a DC partial discharge detection method based on X-ray excitation, comprising:

[0035] The tested product placed in the experimental test bench is subjected to several pressure tests until insulation defects are detected in the tested product or the voltage value corresponding to the pressure test is the maximum voltage value that the tested product can withstand. Among them, the voltage value corresponding to the initial pressure test is the smallest voltage value in the preset step voltage.

[0036] During each pressurization test, it is determined whether partial discharge is detected in the tested product. If partial discharge is detected, it is determined that the tested product has insulation defects; if partial discharge is not detected, the electrical signal generated by the tested product after the X-ray source emits a quantitative X-ray pulse is received, and when it is determined that the tested product has partial discharge according to the electrical signal, it is determined that the tested product has insulation defects, and when it is determined that the tested product does not have partial discharge according to the electrical signal, the voltage value of the pressurization module during the pressurization test is increased by one step according to the preset step voltage as the updated voltage value.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The embodiment of the present invention provides a DC partial discharge detection device and method based on X-ray excitation. The device is used to perform several pressure tests on the tested product, and determine whether the tested product has a partial discharge phenomenon during each pressure test. If the partial discharge phenomenon is detected, it is determined that the tested product has an insulation defect. If the partial discharge phenomenon is not detected, the electrical signal generated by the tested product after the X-ray source emits a quantitative X-ray pulse is received, and when it is determined that the tested product has a partial discharge phenomenon according to the electrical signal, it is determined that the tested product has an insulation defect. When it is determined that the tested product does not have a partial discharge phenomenon according to the electrical signal, the voltage value of the pressure module during the pressure test is increased by one step according to the preset step voltage as the updated voltage value. X-rays are an electromagnetic wave with an extremely short wavelength and strong ionization ability. Compared with the traditional method of using extra electrons released by overvoltage to excite partial discharge, X-rays reduce the applied voltage of partial discharge detection, thereby solving the problem of difficulty in extracting partial discharge signals of DC power equipment in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of a DC partial discharge detection device based on X-ray excitation provided by an embodiment of the present invention.

[0040] Figure 2 It is a flow chart of a DC partial discharge detection method based on X-ray excitation provided by one embodiment of the present invention.

[0041] Figure 3 It is a schematic diagram of the change of partial discharge amount of the sample when the pressure test voltage increases continuously with time in the insulation detection experiment of the air gap defect model provided by one embodiment of the present invention.

[0042] Figure 4 It is a schematic diagram of the change of partial discharge amount of the sample when the pressure test voltage of the defect-free model provided by an embodiment of the present invention increases continuously with time in the insulation detection experiment.

[0043] Description of reference numerals:

[0044] 1. Pressurization module; 2. Signal preprocessing module; 3. Detection and processing module; 4. Experimental test bench; 5. X-ray source; 11. Voltage test box; 12. Experimental transformer; 13. Rectifier silicon stack; 14. Protection resistor; 21. Current limiting resistor; 22. Coupling capacitor; 23. Filter capacitor; 24. Voltage divider; 31. Oscilloscope; 32. Multi-device control unit; 33. Data acquisition unit; 34 External detection impedance; 35. Computer. DETAILED DESCRIPTION

[0045] 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. 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.

[0046] like Figure 1 As shown, an embodiment of the present invention provides a DC partial discharge detection device based on X-ray excitation, including: an experimental test bench 4, a pressurizing module 1, a detection processing module 3 and an X-ray source 5.

[0047] The experimental test bench 4 is used to place the tested product.

[0048] In actual operation, the tested product (such as cables, transformers, etc.) is connected to the DC partial discharge detection device. Make sure that all connection parts are stable and reliable to ensure electrical safety and data accuracy during the test.

[0049] The pressurizing module 1 is used to perform several pressurizing tests on the tested product until insulation defects are detected in the tested product or the voltage value corresponding to the current pressurizing test is the maximum voltage value that the tested product can withstand; wherein the voltage value corresponding to the initial pressurizing test is the minimum voltage value in the preset step voltage.

[0050] In the specific implementation, the setting of the voltage value step difference is flexibly adjusted according to the size and characteristics of the tested object. Specifically, as the size of the tested object increases, the voltage value step difference also increases accordingly, so as to improve the detection efficiency and save detection time while ensuring the detection accuracy.

[0051] The detection processing module 3 is used to determine whether partial discharge is detected in the tested product during each pressure test. If partial discharge is detected, it is determined that the tested product has insulation defects; if partial discharge is not detected, the electrical signal generated by the tested product after the X-ray source 5 emits a quantitative X-ray pulse is received, and when it is determined that the tested product has partial discharge according to the electrical signal, it is determined that the tested product has insulation defects, and when it is determined that the tested product does not have partial discharge according to the electrical signal, the voltage value of the pressure module during the pressure test is increased by one step according to the preset step voltage as the updated voltage value.

[0052] It should be noted that the partial discharge detection method of the present invention complies with the IEC60270 international standard, in which the detection threshold of partial discharge is set at 10pC. That is, when a discharge of more than 10pC is detected, it will be regarded as a deterministic discharge. In addition, if the tested product is boosted to the maximum voltage value it can withstand and irradiated with X-ray pulses, and no partial discharge phenomenon is observed, it is considered that the insulation performance of the tested product is qualified, that is, there is no air gap defect of more than 1mm. This conclusion is based on strict experimental conditions and international standards, which ensures the accuracy and reliability of the evaluation results.

[0053] In a preferred embodiment, the present invention uses an XR 270kV pulse light source as an X-ray source, the distance between the exit port and the tested object is 20cm, the energy of each X-ray pulse is 1μSv, and the number of pulses of the X-ray source is set to 20 to ensure that potential partial discharge phenomena can be fully stimulated.

[0054] The detection and processing module can collect and analyze partial discharge signals in real time and output the results to the computer for display and storage. The system bandwidth of the detection and processing module is set to 300kHz, the center frequency is 250kHz, and the detection sensitivity can reach 10fC, which can accurately detect weak partial discharge signals.

[0055] like Figure 1 As shown, in an optional embodiment, the DC partial discharge detection device based on X-ray excitation, in addition to the above-mentioned experimental test bench 4, pressurization module 1, detection processing module 3 and X-ray source 5, also includes a signal preprocessing module 2:

[0056] The signal preprocessing module 2 is used to perform noise suppression, filtering and amplitude adjustment on the electrical signal generated by the tested product during the detection process, and transmit the processed electrical signal to the detection processing module.

[0057] like Figure 1As shown, in a preferred embodiment, the DC partial discharge detection device based on X-ray excitation includes an experimental test bench 4, a pressurization module 1, a signal preprocessing module 2, a detection processing module 3 and an X-ray source 5, wherein the pressurization module 1 includes a voltage withstand test box 11, an experimental transformer 12, a rectifier silicon stack 13 and a protection resistor 14: the signal preprocessing module 2 includes a current limiting resistor 21, a coupling capacitor 22, a filter capacitor 23 and a voltage divider 24: the detection processing module 3 includes an oscilloscope 31, a multi-device control unit 32, a data acquisition unit 33, an external detection impedance 34 and a computer 35.

[0058] The grounding terminal of the withstand voltage test box 11 is grounded, and the output terminal of the withstand voltage test box 11 is connected to the input terminal of the test transformer 12 .

[0059] The output end of the experimental transformer 12 is connected to the input end of the rectifier silicon stack 13 .

[0060] The output end of the rectifying silicon stack 13 is connected to the input end of the protection resistor 14 .

[0061] The output end of the protection resistor 14 is connected to the input end of the current limiting resistor 21 in the signal preprocessing module 2 .

[0062] The input end of the current limiting resistor 21 is also connected to the input end of the filter capacitor 23 .

[0063] The output end of the current limiting resistor 21 is connected to the input end of the coupling capacitor 22 .

[0064] The input terminal of the coupling capacitor 22 is also connected to the input terminal of the voltage divider 24 .

[0065] The output end of the coupling capacitor 22 is connected to the input end of the experimental test bench 4 .

[0066] The ground terminal of the coupling capacitor 22 is connected to the input terminal of the oscilloscope 31 in the detection processing module 3 .

[0067] The output end of the voltage divider 24 is connected to the IN input end of the external detection impedance 34 in the detection processing module 3 .

[0068] The output terminal of the filter capacitor 23 is grounded.

[0069] The output terminal of the experimental test bench 4 is grounded.

[0070] The input terminal 31 of the oscilloscope is also connected to the AC terminal of the data acquisition unit 33 .

[0071] The PD terminal of the external detection impedance 34 is connected to the BNC terminal of the data acquisition unit 33 .

[0072] The ground terminal of the external detection impedance 34 is connected to the ground.

[0073] The LC terminal of the data acquisition unit 33 is connected to the input terminal of the multi-device control unit 32 .

[0074] An output terminal of the multi-device control unit 32 is connected to an input terminal of a computer 35 .

[0075] like Figure 2 As shown, an embodiment of the present invention provides a DC partial discharge detection method based on X-ray excitation, which at least includes the following steps:

[0076] Step S1: Perform several pressure tests on the tested product placed in the experimental test bench until an insulation defect is detected in the tested product or the voltage value corresponding to the pressure test is the maximum voltage value that the tested product can withstand. The voltage value corresponding to the initial pressure test is the minimum voltage value in the preset step voltage.

[0077] Step S2: during each pressurization test, determine whether partial discharge is detected in the tested product. If partial discharge is detected, determine that the tested product has insulation defects; if partial discharge is not detected, receive the electrical signal generated by the tested product after the X-ray source emits a quantitative X-ray pulse, and when it is determined that the tested product has partial discharge according to the electrical signal, determine that the tested product has insulation defects, and when it is determined that the tested product does not have partial discharge according to the electrical signal, adjust the voltage value of the pressurization module during the pressurization test by one step as the updated voltage value according to the preset step voltage.

[0078] An embodiment of the present invention provides a defective sample insulation test based on the above device item. In the experiment, the discharge characteristics of a truncated cone-shaped epoxy resin block sample with an air gap of 30 mm in diameter and 0.5 mm in height (air gap defect model) and a truncated cone-shaped epoxy resin block sample without an air gap defect (non-defect model) under the same conditions are compared.

[0079] The two groups of samples were connected to the DC partial discharge detection device to ensure that the connection was stable and the electrical performance was good. The number of pulses of the X-ray source was set to 20, and the air gap defect model was tested for partial discharge by step-by-step boosting and emitting X-ray pulses. Figure 3 , Figure 4 As shown, the chart is a combination of a line chart and a bar chart. The line chart part shows the voltage change trend over time, with the left vertical axis representing voltage and the horizontal axis representing time; the bar chart part shares the time axis with the line chart, and the right vertical axis represents the local discharge amount. The bar chart is used to represent the local discharge amount at a specific time point.

[0080] like Figure 3As shown in the figure, when the applied voltage reaches 2kV, X-ray excitation is performed. At this time, partial discharge of more than 10pC is observed in the sample. Subsequently, the voltage is continued to increase, and X-ray excitation and partial discharge detection are performed at each voltage level. The results show that as the voltage increases, the amount of partial discharge gradually increases. When the voltage reaches 7kV, spontaneous partial discharge occurs in the sample, that is, the discharge phenomenon can be detected without external X-ray excitation.

[0081] The same operation is performed on the non-defective model on the same DC partial discharge detection device. Figure 4 As shown in the figure, no partial discharge phenomenon was observed after multiple X-ray excitations and partial discharge detections within the 10kV voltage range. This result confirms that the sample is defect-free.

[0082] In the experiment of the air gap defect model, the device was able to sensitively detect partial discharge phenomena. This proves that the X-ray excitation technology can effectively stimulate potential discharge phenomena and capture these signals through the corresponding detection mechanism. In the experiment of the defect-free model, the device did not make any misjudgments, that is, no partial discharge phenomena were detected incorrectly. This further verifies the accuracy and reliability of the detection method.

[0083] Since it can accurately distinguish between defective and non-defective DUTs, the detection method has a high degree of accuracy in evaluating the insulation condition of the DUT. This is essential to ensure the safe operation of electrical equipment. By giving correct measurement results, the device can not only help engineers and technicians to find potential insulation problems in a timely manner, but also provide them with effective solutions and improvement suggestions. Compared with traditional detection methods, the DC partial discharge detection method based on X-ray excitation has higher detection efficiency. This is mainly due to the fast response and high efficiency characteristics of X-ray excitation technology. In addition, the device can also quickly screen a large number of DUTs, thereby greatly saving detection time and cost. This makes the detection method have broad application prospects in industrial production, power system maintenance and other fields. The DC partial discharge detection test device and detection method based on X-ray excitation show high efficiency, sensitivity and accuracy in detecting the insulation condition of the DUT. This achievement not only provides a new solution for insulation monitoring of electrical equipment, but also provides strong technical support for research and application in related fields.

[0084] It should be noted that the embodiments of the device described above correspond to the above embodiments of the present invention, and can implement any of the methods described above in the present invention. In addition, the embodiments of the above-mentioned device are merely schematic, wherein the modules described as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, in the drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which can be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art can understand and implement it without paying any creative work.

[0085] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0086] 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 DC partial discharge detection device based on X-ray excitation, characterized in that: Including experimental test bench, pressurization module, detection and processing module and X-ray source: The experimental test bench is used to place the tested product; The pressure module is used to perform several pressure tests on the tested product until an insulation defect is detected in the tested product or the voltage value corresponding to the pressure test is the maximum voltage value that the tested product can withstand; wherein the voltage value corresponding to the initial pressure test is the minimum voltage value in the preset step voltage; The detection and processing module is used to determine whether partial discharge is detected in the tested product during each pressure test; if partial discharge is detected, it is determined that the tested product has insulation defects; if no partial discharge is detected, it is used to receive the electrical signal generated by the tested product after the X-ray source emits a quantitative X-ray pulse, and when it is determined that the tested product has partial discharge according to the electrical signal, it is determined that the tested product has insulation defects, and when it is determined that the tested product does not have partial discharge according to the electrical signal, the voltage value of the pressure module during the pressure test is increased by one step according to a preset step voltage as the updated voltage value.

2. The DC partial discharge detection device based on X-ray excitation according to claim 1, characterized in that: Also includes signal preprocessing modules: The signal preprocessing module is used to perform noise suppression, filtering and amplitude adjustment on the electrical signal generated by the tested product during the detection process, and transmit the processed electrical signal to the detection processing module.

3. The DC partial discharge detection device based on X-ray excitation according to claim 2, characterized in that: The pressurization module includes a withstand voltage test box, a test transformer, a rectifier silicon stack and a protective resistor: The grounding terminal of the withstand voltage test box is grounded, and the output terminal of the withstand voltage test box is connected to the input terminal of the test transformer; The output end of the experimental transformer is connected to the input end of the rectifier silicon stack; The output end of the rectifier silicon stack is connected to the input end of the protection resistor; The output end of the protection resistor is connected to the signal preprocessing module.

4. The DC partial discharge detection device based on X-ray excitation according to claim 3, characterized in that: The signal preprocessing module includes a current limiting resistor, a coupling capacitor, a filter capacitor and a voltage divider: The protection resistor output end is connected to the current limiting resistor input end; The input end of the current limiting resistor is also connected to the input end of the filter capacitor; The output end of the current limiting resistor is connected to the input end of the coupling capacitor; The input end of the coupling capacitor is also connected to the input end of the voltage divider; The output end of the coupling capacitor is connected to the input end of the experimental test bench; The ground terminal of the coupling capacitor and the output terminal of the voltage divider are connected to the detection processing module; The output terminal of the filter capacitor is grounded; The output terminal of the experimental test bench is grounded.

5. The DC partial discharge detection device based on X-ray excitation according to claim 4, characterized in that: The detection processing module includes an oscilloscope, a multi-device control unit, a data acquisition unit, an external detection impedance and a computer: The ground terminal of the coupling capacitor is connected to the input terminal of the oscilloscope; The input terminal of the oscilloscope is also connected to the AC terminal of the data acquisition unit; The output end of the voltage divider is connected to the input end of the external detection impedance IN; The PD end of the external detection impedance is connected to the BNC end of the data acquisition unit; The ground terminal of the external detection impedance is grounded; The LC terminal of the data acquisition unit is connected to the input terminal of the multi-device control unit; The output terminal of the multi-device control unit is connected to the input terminal of the computer.

6. The DC partial discharge detection device based on X-ray excitation according to claim 1, characterized in that: The detection threshold of partial discharge is set to 10pC.

7. The DC partial discharge detection device based on X-ray excitation according to claim 1, characterized in that: The voltage value step difference of the preset step voltage is positively correlated with the size of the tested product.

8. The DC partial discharge detection device based on X-ray excitation according to claim 1, characterized in that: The X-ray source is an XR 270kV pulse light source; wherein the distance between the X-ray source outlet and the tested object is 20cm, and the energy of each X-ray pulse is 1μSv.

9. The DC partial discharge detection device based on X-ray excitation according to claim 5, characterized in that: The oscilloscope is a Teledyne high-speed oscilloscope WafeSurfer510, with a bandwidth of 1 GHz and a maximum sampling rate of 10 GS / s.

10. A DC partial discharge detection method based on X-ray excitation, characterized in that: include; The tested product placed in the experimental test bench is subjected to several pressure tests until insulation defects are detected in the tested product or the voltage value corresponding to the pressure test is the maximum voltage value that the tested product can withstand; wherein, the voltage value corresponding to the initial pressure test is the minimum voltage value in the preset step voltage; During each pressure test, it is determined whether partial discharge is detected in the tested product; if partial discharge is detected, it is determined that the tested product has insulation defects; if no partial discharge is detected, an electrical signal generated by the tested product after the X-ray source emits a quantitative X-ray pulse is received, and when it is determined that partial discharge is present in the tested product based on the electrical signal, it is determined that the tested product has insulation defects, and when it is determined that no partial discharge is present in the tested product based on the electrical signal, the voltage value of the pressure module during the pressure test is increased by one step according to the preset step voltage as the updated voltage value.

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