A multi-band series resonant high-voltage test device and its impedance matching method

Abstract

This invention relates to the field of insulation performance testing technology, specifically to a multi-band series resonant high-voltage testing device and its impedance matching method. The method involves multi-band frequency sweeping of the device under test (DUT) to acquire and finely sweep the target frequency band. Based on the frequency, peak width, and amplitude of the peak points during the fine sweep, a reference degree is obtained to screen out the true resonant points within the target frequency band. The load on the DUT is adjusted, and based on the changes in the reference degree, quality factor, and amplitude of the true resonant points under different loads, a predominance degree is obtained to distinguish between the main resonant point and local resonant points. Impedance matching is performed based on the frequency of the main resonant point to conduct a voltage boost test. The insulation performance of the DUT is evaluated for each voltage boost test based on the predominance degree of the main resonant point and the number of local resonant points after voltage boost. This invention effectively improves the accuracy of impedance matching and insulation assessment by accurately screening out the main resonant point, avoiding test deviations caused by interference, and ensuring the reliability and safety of high-voltage testing.

Description

Technical Field

[0001] This invention relates to the field of insulation performance testing technology, specifically to a multi-band series resonant high-voltage testing device and its impedance matching method. Background Technology

[0002] In power systems and industrial electrical fields, the insulation performance of core power equipment such as large transformers and high-voltage reactors directly determines the safe and stable operation of the entire system. High-voltage testing is a key means of verifying the insulation status of such equipment. Its core objective is to accurately identify weak points in the insulation by simulating the extreme voltage environment during equipment operation, thus preventing equipment failures caused by insulation breakdown in actual operation. Multi-band series resonant high-voltage testing equipment has become the mainstream equipment for high-voltage insulation testing due to its advantages such as low energy loss, high test voltage amplitude, and waveform close to power frequency. This type of equipment adjusts the excitation frequency of the variable frequency power supply to make the test circuit resonate in series with the equipment under test, thereby generating high voltage across the equipment under test to achieve insulation performance assessment. Its core logic is to conduct testing based on the resonant characteristics of the equipment under test, and the accurate identification of the resonant point and the effective selection of the main resonant point are prerequisites for ensuring the accuracy of the test.

[0003] However, existing multi-band series resonant high-voltage testing technology does not take into account the complex electromagnetic interference that the device under test (DUT) will be subject to in practical applications, which can easily lead to false resonant points in the test data. At the same time, the internal structure of the DUT is complex, naturally forming a complex network of multiple capacitors and inductors, which can easily generate multiple local resonant points. This makes it impossible to accurately identify the main resonant point that reflects the overall insulation state of the DUT, which in turn can lead to impedance matching deviation, uneven test voltage distribution and local overvoltage, affecting the accuracy and reliability of the insulation performance assessment of the DUT and making it difficult to meet the stringent testing requirements of core power equipment. Summary of the Invention

[0004] To address the technical problem that existing multi-band series resonant high-voltage testing techniques cannot accurately identify the main resonant point reflecting the overall insulation state of the device under test, thus hindering accurate evaluation of the device's insulation performance, this invention aims to provide a multi-band series resonant high-voltage testing device and its impedance matching method. The specific technical solution adopted is as follows:

[0005] In a first aspect, one embodiment of the present invention provides an impedance matching method for a multi-band series resonant high-voltage test device, the method comprising the following steps:

[0006] Perform multi-band frequency sweep test on the device under test to obtain the current amplitude-frequency curve of the device under test and each frequency band under test in the current amplitude-frequency curve;

[0007] For each frequency band to be tested, a predetermined number of fine scans are performed. The target fine scan for each frequency band to be tested is determined based on the peak points in each fine scan. Based on the similarity of each peak point in the target fine scan of each frequency band to be tested with the peak points in other fine scans in terms of frequency, peak width, and amplitude, as well as the size and symmetry of the peak width, the reference degree of each peak point in the target fine scan is obtained, and then the true resonant points in each frequency band to be tested are selected.

[0008] Adjust the load of the device under test, and based on the reference degree and quality factor of each real resonant point under different loads, as well as the change in amplitude, obtain the degree of dominance of each real resonant point, and then distinguish the main resonant point from the local resonant point;

[0009] Impedance matching is performed based on the frequency corresponding to the main resonant point. After impedance matching, the device under test is subjected to a voltage boost test with a preset step size. The insulation performance of the device under test is evaluated based on the degree of dominance of the main resonant point and the change in the degree of dominance after each voltage boost, as well as the increase in the number of local resonant points.

[0010] Furthermore, the method for obtaining the target fine scan is as follows:

[0011] For any frequency band to be tested, the number of peak points of the frequency band to be tested in each specified fine scan is obtained and used as the reference number;

[0012] The specified fine scan corresponding to the largest reference quantity is taken as the target fine scan for the frequency band under test.

[0013] Furthermore, the method for obtaining the peak width is as follows:

[0014] For any specified fine scan of any frequency band to be measured, the mean value of the current amplitude corresponding to all frequencies except for all peak points and one adjacent frequency point in the specified fine scan is obtained as the current segmentation value of the specified fine scan.

[0015] For any peak point in the current amplitude-frequency curve corresponding to the specified fine scan, frequency points are searched one by one from the peak point towards the low frequency direction. When the first point with a current amplitude less than or equal to the current division value is found, it is taken as the target point to the left of the peak point.

[0016] From the peak point, frequency points are searched one by one in the high-frequency direction. When the first point with a current amplitude less than or equal to the current division value is found, it is taken as the target point to the right of the peak point.

[0017] The length of the frequency band formed by the frequencies corresponding to the left and right target points is taken as the peak width of the peak point.

[0018] Furthermore, the method for obtaining the reference level is as follows:

[0019] For any frequency band to be measured, all other fine scans other than the target fine scan of the frequency band to be measured shall be used as reference fine scans of the frequency band to be measured, and the peak points in the current amplitude-frequency curves corresponding to each reference fine scan shall be used as reference peak points.

[0020] For any peak point in the fine scan of the target frequency band under test and any reference peak point in any reference fine scan, the result of normalizing the difference between the frequency corresponding to the peak point and the reference peak point is used as the first analysis value.

[0021] The result of normalizing the difference in peak width between the peak point and the reference peak point is used as the second analytical value.

[0022] The result of normalizing the difference in amplitude between the peak point and the reference peak point is used as the third analysis value.

[0023] The sum of the first, second, and third analytical values, followed by negative correlation and normalization, is used as the degree of matching between the peak point and the reference peak point.

[0024] The matching degree between the peak point and each reference peak point in the reference fine scan is obtained and used as the reference matching degree. When the maximum reference matching degree is greater than the preset matching degree threshold, the reference peak point corresponding to the maximum reference matching degree is used as the matching peak point of the peak point in the reference fine scan.

[0025] When the maximum reference matching degree is less than or equal to the preset matching degree threshold, there is no matching peak point in the reference fine scan;

[0026] The average of the reference matching degree between the peak point and each of its matching peak points is obtained and used as the matching analysis value of the peak point;

[0027] The result of negatively correlating the absolute values ​​of the tangent slopes corresponding to the target points to the left and right of the peak point is used as the degree of symmetry of the peak point.

[0028] The result of normalizing the product of the peak width, symmetry, matching analysis value, and number of matching peak points of the peak point is used as the reference level of the peak point.

[0029] Furthermore, the method for obtaining the actual resonant point is as follows:

[0030] When the reference level is greater than the preset reference level threshold, the corresponding peak point is taken as the true resonant point.

[0031] Furthermore, the method for obtaining the degree of importance is as follows:

[0032] Adjust the load of the device under test in the specified order, and obtain the reference level, quality factor and corresponding amplitude of each true resonant point after each load adjustment;

[0033] For any true resonant point, the amplitude corresponding to each load adjustment at the true resonant point is arranged according to the load adjustment order to obtain the amplitude sequence of the true resonant point.

[0034] The difference between each amplitude in the amplitude sequence and its previous adjacent amplitude is taken as the first difference;

[0035] The mean and standard deviation of the first difference are added together, negatively correlated, and normalized. This result is taken as the first principal analytical value of the true resonance point.

[0036] The average of the reference level after all load adjustments at the true resonant point is taken as the second principal analytical value of the true resonant point.

[0037] The average quality factor after all load adjustments at the true resonant point is taken as the third principal analytical value of the true resonant point.

[0038] The normalized product of the first, second, and third principal analytical values ​​of the true resonant point is taken as the degree of principality of the true resonant point.

[0039] Furthermore, the method for obtaining the main resonant point and the local resonant point is as follows:

[0040] The true resonance point corresponding to the greatest degree of preponderance is taken as the principal resonance point;

[0041] All real resonant points other than the main resonant point are considered as local resonant points.

[0042] Furthermore, the method for evaluating the insulation performance of the device under test in each voltage boost test is as follows:

[0043] For any given boost test, the degree of dominance of the main resonance point under that boost test and each boost test prior to that boost test is arranged according to the boost test sequence to obtain a sequence of dominance.

[0044] The difference between each majority in the majority sequence and its preceding adjacent majority is taken as the second difference;

[0045] The second difference that is negative is taken as the reference difference. The product of the number of reference differences and the absolute value of the smallest reference difference is negatively correlated and normalized, and the result is taken as the first insulation analysis value of this voltage boost test.

[0046] The second insulation analysis value for this voltage boost test is obtained by negatively correlating and normalizing the difference between the number of local resonant points in this voltage boost test and the number of local resonant points in the first voltage boost test.

[0047] The normalized result of the product of the primary degree of this voltage boost test, the first insulation analysis value, and the second insulation analysis value is taken as the insulation degree of this voltage boost test;

[0048] When the insulation level is less than the preset insulation level threshold, it is determined that the insulation performance of the device under test is abnormal during this voltage boost test.

[0049] When the insulation level is greater than or equal to the preset insulation level threshold, the insulation performance of the device under test is determined to be normal under this voltage boost test.

[0050] Furthermore, the method for obtaining the frequency band to be tested is as follows:

[0051] For any maximum point in the current amplitude-frequency curve, a continuous frequency band is formed by extending a preset length to both sides of the frequency corresponding to the maximum point as a test frequency band.

[0052] Secondly, another embodiment of the present invention provides a multi-band series resonant high voltage testing device, the device comprising: a memory, a processor, and a computer program stored in the memory and running on the processor, wherein when the processor executes the computer program, it implements the steps of any of the above methods.

[0053] The present invention has the following beneficial effects:

[0054] This invention first performs a predetermined number of fine scans on each frequency band under test. Based on the peak points in each fine scan, a target fine scan for each frequency band is determined. This facilitates subsequent focusing on effective data intervals, eliminates interference from invalid fine scans, and improves the efficiency of resonant point identification. Furthermore, based on the similarity of each peak point in the target fine scan of each frequency band to peak points in other fine scans in terms of frequency, peak width, and amplitude, as well as the size and symmetry of the peak width, the reference level of each peak point in the target fine scan is obtained. This accurately reflects the reproducibility and stability of each peak point, which is beneficial for quantitatively distinguishing between true feature points and interference spikes. This allows for accurate screening of true resonant points in each frequency band under test, facilitating the subsequent elimination of false resonant points and laying a reliable data foundation for resonant point classification. To further verify the inherent properties of resonant points and distinguish between overall and local characteristics of the device, the load on the device under test is adjusted. Based on the reference level of each true resonant point under different loads... By analyzing the degree, quality factor, and amplitude changes, the predominance of each true resonant point is obtained, accurately reflecting the degree to which each true resonant point represents the overall electromagnetic characteristics of the equipment. This allows for accurate differentiation between the main resonant point and local resonant points, facilitating subsequent locking of the core resonant reference and ensuring the accuracy of impedance matching. To optimize energy and accurately assess insulation performance during high-voltage testing, impedance matching is performed based on the frequency corresponding to the main resonant point. After impedance matching, a voltage boost test with a preset step size is conducted on the equipment under test, which helps reduce energy loss in the test circuit and avoids damage to the equipment from local overvoltage. Furthermore, based on the predominance and changes in the predominance of the main resonant point after each voltage boost, as well as the increase in the number of local resonant points, the insulation performance of the equipment under test is accurately assessed for each voltage boost test. This allows for real-time detection of insulation degradation trends and early warning of potential fault risks, effectively improving the accuracy, safety, and reliability of multi-band series resonant high-voltage testing. Attached Figure Description

[0055] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 A schematic flowchart illustrating an impedance matching method for a multi-band series resonant high-voltage test device according to an embodiment of the present invention;

[0057] Figure 2 This is a structural diagram of an impedance matching system for a multi-band series resonant high-voltage test device according to an embodiment of the present invention;

[0058] Figure 3This is a schematic diagram of a computer device provided according to an embodiment of the present invention. Detailed Implementation

[0059] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a multi-band series resonant high-voltage test device and its impedance matching method proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0061] The following description, in conjunction with the accompanying drawings, details the specific scheme of the multi-band series resonant high-voltage test equipment and its impedance matching method provided by the present invention.

[0062] Example 1:

[0063] This invention proposes an impedance matching method for a multi-band series resonant high-voltage test device. Please refer to [link / reference]. Figure 1 The diagram illustrates a schematic flowchart of an impedance matching method for a multi-band series resonant high-voltage test device according to an embodiment of the present invention. The method includes the following steps:

[0064] Step S1: Perform a multi-band frequency sweep test on the device under test to obtain the current amplitude-frequency curve of the device under test and each frequency band under test in the current amplitude-frequency curve.

[0065] Specifically, this embodiment uses a large transformer as the device under test (DUT) to obtain its frequency response characteristics under series resonance test conditions. Specifically, the output of a frequency response analyzer is connected to the input of a multi-band series resonance high-voltage test device, and the output of the multi-band series resonance high-voltage test device is then connected to the test winding terminal of the DUT. To ensure the safety and accuracy of the test circuit, all non-test windings and the casing of the DUT must be reliably grounded to form a complete test circuit. A high-frequency response current sensor is connected in series in the test circuit to acquire the circuit current signal in real time; a high-voltage withstand voltage sensor is connected in parallel across the test winding to synchronously monitor the winding terminal voltage. It should be noted that the current sensor and voltage sensor must undergo zero-point calibration and accuracy verification before installation. The signal output terminals of the current sensor and voltage sensor are connected to the data processing unit via a double-shielded coaxial cable to ensure the real-time performance and integrity of the acquired data.

[0066] To balance the efficiency and accuracy of resonant point scanning, this embodiment employs a phased strategy of coarse scanning followed by target frequency band locking. The core purpose of coarse scanning is to quickly locate the approximate range of potential resonant points across a wide frequency band, narrowing the scanning range for subsequent fine scanning and avoiding the inefficiency caused by full-band fine scanning. It should be noted that the scanning frequency band for coarse scanning covers the common resonant frequency bands of large transformers, typically 10kHz-200kHz (adjusted according to transformer capacity; when the transformer capacity is greater than or equal to 100MVA, the lower limit of the resonant frequency band can be appropriately lowered to 5kHz). This embodiment sets the step size for coarse scanning to 1kHz (balancing scanning efficiency and initial positioning accuracy; a step size that is too wide may miss resonant points, while a step size that is too narrow will prolong the scanning time). The excitation signal amplitude for coarse scanning is set to 5% of the rated test voltage (to avoid potential damage to the transformer insulation caused by high voltage during the coarse scanning stage, while ensuring that the current signal amplitude meets the sensor's measurement sensitivity requirements). Implementers can set the scanning frequency band, step size, and excitation signal amplitude for coarse scanning according to actual conditions; these are not limited here.

[0067] The multi-band series resonant high-voltage test equipment and frequency response analyzer are started, and a coarse scan is performed according to the set parameters: the frequency response analyzer outputs a sinusoidal excitation signal from low to high in 1kHz steps, which is amplified by the multi-band series resonant high-voltage test equipment and then input to the winding under test; the data processing unit synchronously collects the current data and voltage data corresponding to each frequency point, and plots a wide-band current amplitude-frequency curve based on the current data (the horizontal axis is frequency, in kHz; the vertical axis is current amplitude, in A); after the coarse scan is completed, the current amplitude-frequency curve is characterized and all the maximum points in the current amplitude-frequency curve are marked; for any maximum point, a continuous frequency band is formed by extending a preset length to both sides of the frequency corresponding to the maximum point as the center, which is taken as a frequency band to be tested. In this embodiment, the preset length is set to 1 coarse scan step size. The implementer can set the size of the preset length according to the actual situation, which is not limited here. For example, if the frequency corresponding to a certain maximum point in the current amplitude-frequency curve is 50kHz, then the frequency band to be measured corresponding to that maximum point is 49kHz-51kHz; if the distance between multiple maximum points is less than 2kHz, that is, the extended frequency bands overlap, then they are merged into one frequency band to be measured to avoid repeated scanning.

[0068] At this point, each frequency band to be measured in the current amplitude-frequency curve has been obtained.

[0069] By constructing the test circuit and performing phased scanning as described above, the basic response data of the device under test under series resonant excitation can be effectively obtained. Furthermore, through grounding optimization, sensor calibration, and coarse scanning strategies, external interference and measurement errors are minimized, laying a reliable data foundation for subsequent screening of the true resonant point and determination of the main resonant point.

[0070] Step S2: Perform a preset number of specified fine scans on each frequency band to be tested. Determine the target fine scan for each frequency band to be tested based on the peak points in each specified fine scan. Based on the similarity of each peak point in the target fine scan of each frequency band to be tested with the peak points in other fine scans in terms of frequency, peak width and amplitude, as well as the size and symmetry of the peak width, obtain the reference degree of each peak point in the target fine scan, and then screen out the true resonant points in each frequency band to be tested.

[0071] Specifically, it is known that the device under test (DUT) is typically deployed in strong electromagnetic environments such as substations and power plants. External electromagnetic energy, such as power frequency interference from surrounding high-voltage transmission lines and radiation interference from high-frequency communication equipment, can randomly superimpose onto the current signal in the test circuit, causing non-resonant peaks in the current amplitude-frequency curve. These noise-induced peaks may have amplitudes comparable to the true resonant point, rendering existing logic that relies solely on whether the current amplitude exceeds a threshold or is the maximum peak of the curve ineffective. This makes it impossible to accurately distinguish between noise interference points and true resonant points, leading to subsequent impedance matching deviations and distortions in insulation performance assessments.

[0072] Considering that the true resonant point is an inherent property of the capacitance-inductance network of the device under test (DUT), its generation depends on the series resonance condition where the test signal frequency matches the natural frequency of the transformer's equivalent circuit. Therefore, excluding irreversible changes such as equipment structural damage and insulation aging, the appearance of the true resonant point is fixed when performing multiple fine scans on the same test frequency band. That is, the frequency, current amplitude, and peak shape of the corresponding peak point remain highly consistent in multiple fine scan tests, without random drift or disappearance. In addition, the current peak corresponding to the true resonant point is not an isolated sharp pulse, but a complete peak shape with a certain width. This is because there is a certain energy loss in the transformer's equivalent circuit (such as copper loss and iron loss), which makes the change in current amplitude under resonance state show a trend of gradual rise-peak value-gradual decrease, with a relatively large peak width and high peak symmetry.

[0073] Noise interference points are caused by random injection of external electromagnetic energy or instantaneous fluctuations of internal parasitic parameters. Their essence is the signal superposition effect under non-resonant conditions. Therefore, they will exhibit characteristics completely opposite to the true resonant points. Noise interference points are difficult to repeat in multiple fine scans. That is, when the same frequency band is tested continuously, the noise peak point that appears in a certain fine scan may completely disappear in subsequent fine scans, or its corresponding frequency and amplitude may drift significantly, with no fixed recurrence pattern. In addition, the current peak corresponding to the noise interference point is usually an isolated sharp peak with a very small peak width. This is because the injection of noise energy has instantaneous and narrow frequency band characteristics, which only causes a brief increase in current amplitude within a very narrow frequency range. The current amplitude on both sides of the peak point quickly falls back to the normal level, forming a sharp, isolated peak shape with poor peak symmetry, often accompanied by obvious spikes or steep edges.

[0074] To accurately detect the true resonant point, this embodiment first performs a preset number of specified fine scans on each frequency band under test. Based on the peak points in each specified fine scan, a target fine scan for each frequency band under test is determined, which facilitates more accurate and efficient identification of the true resonant point in each frequency band under test. Then, based on the similarity of each peak point in the target fine scan of each frequency band under test with the peak points in other fine scans in terms of frequency, peak width, and amplitude, as well as the size and symmetry of the peak width, the reference level of each peak point in the target fine scan is obtained. The greater the reference level, the more likely the corresponding peak point is to be the true resonant point. Thus, the true resonant point in each frequency band under test can be accurately screened based on the reference level. In this embodiment, the preset number is set to 3, and the step size of the specified fine scan is set to 1 / 50 of the coarse scan step size. Implementers can set the preset number and the specified fine scan step size according to actual conditions; no limitation is imposed here. To ensure accurate identification of the true resonant point in each frequency band under test through the fine scan results, the preset number should be no less than 3.

[0075] Preferably, in one feasible method of this embodiment, the method for obtaining the target fine scan is as follows: for any frequency band to be tested, the number of peak points of the frequency band to be tested in each specified fine scan is obtained and used as a reference number; the larger the reference number, the more peak points the specified fine scan covers. In order to avoid the situation of missing the resonant point, the specified fine scan corresponding to the largest reference number is used as the target fine scan of the frequency band to be tested.

[0076] Preferably, in one feasible embodiment of this method, the peak width is obtained as follows: for any specified fine scan of any frequency band to be measured, the average value of the current amplitude corresponding to all frequencies except for all peak points and their adjacent frequency points in the specified fine scan is obtained as the current segmentation value of the specified fine scan; considering that there may be isolated sharp peaks caused by noise in the fine scan curve, which will significantly increase the average value of the current amplitude of all frequencies, making the peak width of subsequent peak points inaccurate, therefore, this embodiment removes the current amplitude corresponding to all peak points and their adjacent frequency points in the specified fine scan, effectively avoiding the high amplitude of the true resonance peak or noise peak. The average value of the interference data is calculated to ensure that the current segmentation value can reflect the background current level of the test circuit and meet the peak width determination requirements of the real resonant point. For any peak point in the current amplitude-frequency curve corresponding to the specified fine scan, frequency points are searched one by one from the peak point to the low frequency direction. When the first point with a current amplitude less than or equal to the current segmentation value is found, it is taken as the left target point of the peak point. Frequency points are searched one by one from the peak point to the high frequency direction. When the first point with a current amplitude less than or equal to the current segmentation value is found, it is taken as the right target point of the peak point. The length of the frequency band formed by the frequencies corresponding to the left and right target points is taken as the peak width of the peak point.

[0077] It should be noted that if the peak point is located at the boundary of the frequency band under test, resulting in the absence of a target point on one side, the current amplitude curve of the target frequency band under test is extended outward by 1-2 fine scan steps. The current amplitude at the extended point is calculated by linear interpolation of the current amplitude at the adjacent point and the current segmentation value, and then the target point is retrieved. For example, if the peak point is located at the low-frequency boundary of the frequency band under test and there is no target point on the left, the current amplitude-frequency curve corresponding to the frequency band under test is extended in the low-frequency direction by 1 fine scan step. The current amplitude at the extended point is calculated by linear interpolation of the current amplitude at the adjacent frequency point to the left of the peak point and the current segmentation value. Value calculation: Specifically, assuming the current amplitude of the point adjacent to the left of the peak point is 0.8A and the current division value is 0.5A, the current amplitude corresponding to the extended point is: 0.8A - (0.8A - 0.5A) × (extension step size / distance between the peak point and the adjacent frequency point on the left). After extension, the extended point is checked according to the target point determination condition to see if the current amplitude is less than or equal to the current division value. If it is, it is taken as the target point; if it is not, it continues to extend by 1 step size (maximum extension of 2 steps). If it is still not satisfied, the farthest point after extension is taken as the target point to avoid over-extension causing peak width distortion. If the current amplitude corresponding to the points between the peak point and the adjacent peak point on the right is greater than the current division value, the average of the frequencies corresponding to the peak point and the adjacent peak point on the right is taken as the frequency corresponding to the target point on the right of the peak point, and also the frequency corresponding to the target point on the left of the adjacent peak point on the right of the peak point.

[0078] Preferably, in one feasible embodiment of this invention, the method for obtaining the reference level is as follows: For any frequency band to be tested, all other fine scans besides the target fine scan of the frequency band to be tested are taken as reference fine scans of the frequency band to be tested, and the peak points in the current amplitude-frequency curves corresponding to each reference fine scan are taken as reference peak points; for any peak point in the target fine scan of the frequency band to be tested and any reference peak point in any of its reference fine scans, the result of normalizing the absolute value of the difference between the frequency corresponding to the peak point and the reference peak point is taken as the first analysis value; the result of normalizing the absolute value of the difference between the peak width corresponding to the peak point and the reference peak point is taken as the second analysis value; the result of normalizing the absolute value of the difference between the amplitude corresponding to the peak point and the reference peak point is taken as the third analysis value; the smaller the first analysis value, the second analysis value, and the third analysis value are, the more closely the peak point matches the reference peak point, that is, the more likely the reference peak point is to be a reproduction of the peak point; in this embodiment, the above-mentioned absolute values ​​of difference are normalized by a linear normalization method. The linear normalization method is a well-known technique and will not be elaborated further.

[0079] To accurately analyze the matching between the peak point and the reference peak point, the first, second, and third analytical values ​​are summed, negatively correlated, and normalized. This result is used as the degree of matching between the peak point and the reference peak point. The greater the degree of matching, the more likely the reference peak point is a reproduction of the peak point in the reference fine scan. This embodiment uses... The sum of the first, second, and third analytical values ​​is negatively correlated and normalized, where norm is the normalization function, and linear normalization is used in this embodiment; x represents the sum of the first, second, and third analytical values. To determine whether the peak point reappears in the reference fine scan, the matching degree between the peak point and each reference peak point in the reference fine scan is obtained, and each is used as a reference matching degree. When the maximum reference matching degree is greater than a preset matching degree threshold, the reference peak point corresponding to the maximum reference matching degree is taken as the matching peak point of the peak point in the reference fine scan. When the maximum reference matching degree is less than or equal to the preset matching degree threshold, the peak point does not have a matching peak point in the reference fine scan. In this embodiment, the preset matching degree threshold is set to 0.5. Implementers can set the size of the preset matching degree threshold according to the actual situation, which is not limited here.

[0080] The more matching peaks a peak point has, and the greater the reference matching degree between the peak point and each of its matching peaks, the more frequently the peak point recurs in the reference fine scan, indirectly indicating that the peak point is more stable and more likely to be a true resonant point. Since the peak width corresponding to a true resonant point is relatively large and the peak shape symmetry is high, this embodiment obtains the average of the reference matching degree between the peak point and each of its matching peaks as the matching analysis value of the peak point. The result of negatively correlated between the absolute values ​​of the differences in the absolute values ​​of the tangent slopes corresponding to the left and right target points of the peak point is used as the symmetry degree of the peak point. This embodiment uses the negative of the absolute value of the difference in the absolute values ​​of the tangent slopes as the power of an exponential function with the natural constant as the base. The output of this exponential function is the result of negatively correlated between the absolute values ​​of the differences in the absolute values ​​of the tangent slopes. Finally, the result of normalizing the product of the peak width, symmetry degree, matching analysis value, and the number of matching peaks is used as the reference degree of the peak point. In this embodiment, the peak width, symmetry, matching analysis value, and number of matching peak points of the peak point are normalized using a linear normalization method.

[0081] At this point, the reference level of each peak point in the fine scan of each target frequency band under test is obtained.

[0082] The greater the reference level, the more likely the corresponding peak point is to be the true resonant point in the corresponding frequency band under test. Therefore, this embodiment sets a preset reference level threshold of 0.6. Implementers can set the size of the preset reference level threshold according to the actual situation, which is not limited here. When the reference level is greater than the preset reference level threshold, the corresponding peak point is taken as the true resonant point in the corresponding frequency band under test.

[0083] Thus, the true resonant point in each frequency band to be tested is accurately selected.

[0084] Step S3: Adjust the load of the device under test. Based on the reference degree and quality factor of each real resonant point under different loads, as well as the change in amplitude, obtain the degree of dominance of each real resonant point, and then distinguish between the main resonant point and the local resonant point.

[0085] Specifically, the device under test (DUT) is known to have an internal electrical circuit that is not a single circuit, but a complex capacitor-inductor network composed of inter-winding capacitance, inter-turn capacitance, and winding inductance. This structural characteristic means that in series resonant high-voltage testing, the current amplitude-frequency curve will not only show a main resonant peak reflecting the overall electrical characteristics of the transformer, but also generate multiple local resonant peaks due to the coupling effect of local capacitance and corresponding inductance. If the main resonant point and local resonant points cannot be effectively distinguished, and high-voltage testing is carried out directly based on all real resonant points, there will be significant safety risks and test deviations: the equivalent circuit corresponding to a local resonant point is limited to a local area of ​​the winding, and its insulation withstand capability is much lower than that of the entire winding. If it is mistakenly used as the main resonant point to apply full voltage for high-voltage testing, it is very easy to induce overvoltage in the local area, which may lead to inter-turn or inter-section insulation breakdown and cause permanent damage to the equipment; at the same time, the existence of local resonant points will also interfere with the stable transmission and accurate matching of the test signal, ultimately affecting the authenticity of the insulation assessment results. Therefore, accurately distinguishing between the main resonant point and local resonant points among the real resonant points is a key link to ensure the safety and accuracy of insulation performance testing.

[0086] It is known that the main resonant point corresponds to the entire winding circuit of the transformer, with large electromagnetic inertia. Under changes in operating conditions such as load adjustment and voltage fluctuation, its resonant frequency, peak shape, and amplitude remain stable. In contrast, the local resonant point originates from the local capacitance and inductance between turns and segments within the winding, with small electromagnetic inertia, high sensitivity to changes in operating conditions, and its resonant parameters are prone to significant drift. On the other hand, the main resonant point is the inherent resonant frequency of the transformer's overall equivalent circuit, with the lowest energy loss and the strongest energy storage capacity, resulting in the highest quality factor. The local resonant point only corresponds to the energy coupling in a local area, with greater energy loss and a significantly lower quality factor than the main resonant point. The quality factor is a well-known technique and will not be elaborated further.

[0087] Therefore, this embodiment actively adjusts the load of the device under test, and obtains the degree of dominance of each real resonant point based on the reference degree and quality factor of each real resonant point under different loads, as well as the change in amplitude. The greater the degree of dominance, the more likely the corresponding real resonant point is to be the main resonant point. Thus, the main resonant point and the local resonant point can be distinguished based on the degree of dominance, laying the foundation for subsequent safe and targeted high-voltage testing.

[0088] Preferably, in one feasible embodiment of this invention, the method for obtaining the degree of primacy is as follows: the load of the device under test is adjusted sequentially according to a specified order, and the reference degree and corresponding amplitude of each true resonant point after each load adjustment are obtained sequentially according to the process of step S2. At the same time, the quality factor of each true resonant point after each load adjustment is also obtained. It should be noted that in this embodiment, the specified order is set from low to high, that is, the load of the device under test is adjusted sequentially from low to high according to the fixed position of the load cabinet in the device under test. The implementer can set the specified order according to the actual situation, and it is not limited here.

[0089] Considering that the actual resonant point may deviate after each load adjustment in practice, this embodiment uses the matching degree acquisition method in step S2 to obtain the matching degree between the actual resonant point after each load adjustment and the actual resonant point after the previous adjacent load adjustment, thereby determining the actual resonant point corresponding to each actual resonant point after each load adjustment in the previous load adjustment. It should be noted that if, after a load adjustment other than the first load adjustment, there is no corresponding actual resonant point after the previous adjacent load adjustment for a certain actual resonant point, then this actual resonant point is defaulted to a false resonant point and directly deleted, without further analysis; therefore, the actual resonant points analyzed subsequently are all actual resonant points that appear after each load adjustment.

[0090] For any true resonant point, the amplitudes corresponding to each load adjustment are arranged according to the load adjustment order to obtain the amplitude sequence of the true resonant point. The absolute value of the difference between each amplitude in the amplitude sequence and its previous adjacent amplitude is taken as the first difference. It should be noted that the first amplitude in the amplitude sequence does not have a previous adjacent amplitude, therefore, the first difference of the first amplitude in the amplitude sequence is not obtained. When the first difference is smaller and more equal, it indicates that the amplitude of the true resonant point is more stable under different loads, indirectly reflecting that the true resonant point is more likely to be the master resonant point. Therefore, in this embodiment, the mean and standard deviation of the first difference are added together and then negatively correlated and normalized as the first primary analysis value of the true resonant point. The larger the first primary analysis value, the more likely the true resonant point is to be the master resonant point. This embodiment uses... The sum of the mean and standard deviation of the first difference is negatively correlated and normalized; where norm is the normalization function, and linear normalization is used in this embodiment; y represents the sum of the mean and standard deviation of the first difference.

[0091] Further, the average value of the reference level after all load adjustments for the true resonant point is obtained as the second principal analysis value for the true resonant point. The larger the second principal analysis value, the more stable the peak shape and frequency corresponding to the true resonant point are under different loads, and the more likely the true resonant point is to be the principal resonant point. At the same time, the average value of the quality factor after all load adjustments for the true resonant point is obtained as the third principal analysis value for the true resonant point. The larger the third principal analysis value, the more likely the true resonant point is to be the principal resonant point.

[0092] To accurately characterize the probability that the true resonant point is a principal resonant point, the normalized result of the product of the first, second, and third principal analysis values ​​of the true resonant point is taken as the degree of principality of the true resonant point. In this embodiment, the product of the first, second, and third principal analysis values ​​is normalized using a linear normalization method.

[0093] Thus, the degree of principality of each true resonant point is obtained. It is known that the greater the degree of principality, the more likely the corresponding true resonant point is to be a principal resonant point. Therefore, in this embodiment, the true resonant point corresponding to the highest degree of principality is taken as the principal resonant point. If there are at least two true resonant points corresponding to the highest degree of principality, the true resonant point with the largest third principal analysis value is selected as the principal resonant point to ensure its uniqueness, because the quality factor of the principal resonant point is significantly greater than that of the local resonant points. Finally, all true resonant points other than the principal resonant points are taken as local resonant points.

[0094] Step S4: Perform impedance matching based on the frequency corresponding to the main resonant point. After impedance matching, perform a voltage boost test with a preset step size on the device under test. Based on the degree of dominance of the main resonant point and the change in the degree of dominance after each voltage boost, as well as the increase in the number of local resonant points, evaluate the insulation performance of the device under test for each voltage boost test.

[0095] Specifically, the main resonant point, as the core inherent electromagnetic characteristic of the device under test (DUT), is directly related to the overall state of the device's insulation system. Simultaneously, changes in the number of local resonant points reflect the uniformity of capacitance distribution within the DUT under high voltage conditions. When insulation performance deteriorates, the core capacitance distribution is prone to imbalance, leading to decreased stability of the main resonant point and an abnormal increase in the number of local resonant points. Therefore, this embodiment first completes system impedance matching based on the characteristic frequency corresponding to the main resonant point. Then, through a step-by-step voltage ramp-up test with a preset step size, it combines two core indicators—the degree of dominance of the main resonant point and its change, and the increase in the number of local resonant points—to achieve accurate and dynamic evaluation of the DUT's insulation performance. This ensures that the test results truly reflect the DUT's insulation withstand capability at different voltage levels and accurately analyze the DUT's insulation performance.

[0096] The impedance matching process is as follows: The frequency corresponding to the main resonant point is used as the reference frequency for impedance matching. This reference frequency reflects the series resonance characteristics of the core capacitance of the device under test (DUT) and the test system. Further, using existing techniques, the equivalent capacitance to ground of the DUT at the reference frequency is measured. The target inductance required for optimal impedance matching is calculated based on the series resonance principle. Then, by adjusting the inductance value of the adjustable reactor in the test system, the target inductance is gradually approximated, while the current signal and power supply output voltage signal of the test circuit are monitored in real time. When the current in the test circuit reaches its maximum value and the power supply output voltage drops to its minimum value, it indicates that the test system and the DUT have achieved optimal impedance matching. At this point, the energy loss in the circuit is minimal, ensuring optimal accuracy and safety for subsequent high-voltage testing. It should be noted that the method for impedance matching is well-known and will not be elaborated further.

[0097] This embodiment uses the rated voltage of the device under test (DUT) as a benchmark and sets a preset step size to gradually increase the voltage for testing. In this embodiment, the preset step size is set to 10% of the rated voltage. The implementer can set the size of the preset step size according to the actual situation, which is not limited here. At the same time, the maximum voltage after voltage increase is limited to 1.3 times the rated voltage to avoid the actual voltage exceeding the insulation withstand limit and reduce the test risk. The implementer can limit the maximum voltage after voltage increase according to the actual situation, which is not limited here. The test voltage is gradually increased according to the preset step size, and a stable voltage state is maintained for 1-2 minutes after each voltage increase to ensure that the device fully responds to the insulation stress under the current voltage level, while avoiding test errors caused by voltage sudden changes. During the voltage stabilization phase of each voltage increase test, the current amplitude-frequency curve collected is scanned in detail according to the process in step S2, and the main resonance point and local resonance point in the curve are identified simultaneously. The degree of dominance of the main resonance point is calculated, and the number of local resonance points is counted.

[0098] The insulation performance of the device under test (DUT) is directly related to the stability of the main resonant point and the change in the number of local resonant points during the voltage boosting process. When the insulation performance of the DUT is poor, its core capacitance distribution is prone to unevenness, and under high voltage conditions, local capacitance increases are more likely to occur. This leads to a significant decrease in the peak stability of the main resonant point; that is, the dominance of the main resonant point decreases with increasing voltage and is accompanied by unstable fluctuations. Furthermore, the number of local resonant points increases significantly. Therefore, this embodiment evaluates the insulation performance of the DUT for each voltage boost test based on the dominance and changes in the dominance of the main resonant point after each voltage boost, as well as the increase in the number of local resonant points.

[0099] Preferably, in one feasible manner of this embodiment, the method for evaluating the insulation performance of the device under test in each voltage boost test is as follows: for any voltage boost test, the degree of dominance of the main resonant point under the voltage boost test and each voltage boost test prior to the voltage boost test is arranged according to the voltage boost test sequence to obtain a degree of dominance sequence; the difference between each degree of dominance in the degree of dominance sequence and its previous adjacent degree of dominance is taken as a second difference; it should be noted that the first degree of dominance in the degree of dominance sequence does not have a previous adjacent degree of dominance, therefore, the second difference of the first degree of dominance in the degree of dominance sequence is not obtained;

[0100] The negative second difference is taken as the reference difference. When there are more reference differences and the larger the absolute value of the minimum reference difference, it indicates that the degree of the main resonance point decreases more significantly with the increase of voltage. The insulation performance of the device under test is more likely to be abnormal under this voltage boost test. Therefore, the product of the number of reference differences and the absolute value of the minimum reference difference is negatively correlated and normalized as the first insulation analysis value of this voltage boost test. The larger the first insulation analysis value, the less likely the insulation performance of the device under test is to be abnormal under this voltage boost test. In this embodiment, the negative of the product of the number of reference differences and the absolute value of the minimum reference difference is taken as the power of an exponential function with the natural constant as the base. The output of this exponential function is the result of negatively correlated and normalized product of the number of reference differences and the absolute value of the minimum reference difference.

[0101] Further, the difference between the number of local resonant points in this voltage boost test and the number of local resonant points in the first voltage boost test is negatively correlated and normalized to obtain the second insulation analysis value for this voltage boost test. The larger the second insulation analysis value, the more consistent the number of local resonant points in this voltage boost test is with the number of local resonant points in the first voltage boost test, and the less likely there is an abnormality in the insulation performance of the device under test under this voltage boost test. This embodiment uses... The difference between the number of local resonant points in this boost test and the number of local resonant points in the first boost test is negatively correlated and normalized; where norm is the normalization function, and linear normalization is used in this embodiment; n represents the difference between the number of local resonant points in this boost test and the number of local resonant points in the first boost test.

[0102] To comprehensively analyze the insulation performance of the device under test (DUT) during this voltage boost test, the normalized result of the product of the primary insulation level, the first insulation analysis value, and the second insulation analysis value is used as the insulation level for this voltage boost test. A higher insulation level indicates a less likely insulation performance anomaly under this voltage boost test. This implementation uses a linear normalization method to normalize the product of the primary insulation level, the first insulation analysis value, and the second insulation analysis value. This embodiment sets a preset insulation level threshold of 0.6. The implementer can set the preset insulation level threshold according to actual conditions; no limitation is imposed here. When the insulation level is less than the preset insulation level threshold, the insulation performance of the DUT under this voltage boost test is considered abnormal. When the insulation level is greater than or equal to the preset insulation level threshold, the insulation performance of the DUT under this voltage boost test is considered normal. It should be noted that the initial voltage boost test uses the rated voltage as a reference. Therefore, the core function of the initial voltage boost test is to provide reference data; the insulation level is not calculated, and all subsequent voltage boost tests use this reference.

[0103] This allows for real-time assessment of the insulation performance of the device under test during each voltage boost test. This facilitates the timely detection of insulation weaknesses, avoids the risk of equipment damage during high-voltage testing, and provides accurate and quantitative technical basis for diagnosing the insulation status of the device under test, ensuring the safety of the testing process and the reliability of the assessment results.

[0104] In summary, this embodiment performs multi-band frequency sweeping on the device under test (DUT) to acquire and finely scan the target frequency band. Based on the frequency, peak width, and amplitude of the peak points during the fine scan, a reference degree is obtained to screen out the true resonant points within the target frequency band. The load on the DUT is adjusted, and based on the changes in the reference degree, quality factor, and amplitude of the true resonant points under different loads, a predominance degree is obtained to distinguish between the main resonant point and local resonant points. Impedance matching is performed based on the frequency of the main resonant point to conduct a voltage boost test. The insulation performance of the DUT is evaluated for each voltage boost test based on the predominance degree of the main resonant point and the number of local resonant points after voltage boost. This invention effectively improves the accuracy of impedance matching and insulation assessment by accurately screening out the main resonant point, avoiding test deviations caused by interference, and ensuring the reliability and safety of high-voltage testing.

[0105] Example 2:

[0106] This invention also proposes an impedance matching system for a multi-band series resonant high-voltage test device. Please refer to [link to relevant documentation]. Figure 2 The diagram shows an impedance matching system structure of a multi-band series resonant high-voltage test device according to an embodiment of the present invention. The system includes: a test frequency band acquisition module 10, a real resonant point acquisition module 20, a resonant point differentiation module 30, and an insulation performance evaluation module 40.

[0107] The test frequency band acquisition module 10 is used to perform multi-band frequency sweep test on the device under test, and acquire the current amplitude-frequency curve of the device under test and each test frequency band in the current amplitude-frequency curve.

[0108] The real resonant point acquisition module 20 is used to perform a preset number of specified fine scans on each frequency band to be tested, and to determine the target fine scan for each frequency band to be tested based on the peak points in each specified fine scan; based on the similarity of each peak point in the target fine scan of each frequency band to be tested with the peak points in other fine scans in terms of frequency, peak width and amplitude, as well as the size and symmetry of the peak width, the reference degree of each peak point in the target fine scan is obtained, and then the real resonant points in each frequency band to be tested are selected.

[0109] The resonant point differentiation module 30 is used to adjust the load of the device under test, and based on the reference degree and quality factor of each real resonant point under different loads, as well as the change in amplitude, to obtain the main degree of each real resonant point, and thus distinguish the main resonant point from the local resonant point.

[0110] The insulation performance evaluation module 40 is used to perform impedance matching based on the frequency corresponding to the main resonant point. After impedance matching, the device under test is subjected to a voltage boost test with a preset step size. Based on the degree of dominance of the main resonant point and the change in the degree of dominance after each voltage boost, as well as the increase in the number of local resonant points, the insulation performance of the device under test is evaluated for each voltage boost test.

[0111] It should be noted that the system provided in the above embodiments is only an example of the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device can be divided into different functional modules to complete all or part of the functions described above. In addition, the multi-band series resonant high voltage test device and the impedance matching method embodiment of the multi-band series resonant high voltage test device provided in the above embodiments belong to the same concept, and their specific implementation process can be found in the method embodiment, which will not be repeated here.

[0112] Example 3:

[0113] This invention also proposes a multi-band series resonant high-voltage test device, including a memory and a processor. The memory stores executable program code, and the processor calls and executes the executable program code to perform the impedance matching method for a multi-band series resonant high-voltage test device provided in the embodiments of this application. Specifically, the device may be a chip, component, or module. The chip may include a connected processor and memory; the memory stores instructions, and when the processor calls and executes the instructions, the chip can perform the impedance matching method for a multi-band series resonant high-voltage test device provided in the above embodiments.

[0114] In addition, this embodiment also protects a computer device; please refer to [link to relevant documentation]. Figure 3 The computer device includes a memory 401, a processor 402, and a computer program 403 stored in the memory 401 and running on the processor 402. When the processor 402 executes the computer program 403, the computer device can execute any of the impedance matching methods of the multi-band series resonant high voltage test equipment described above.

[0115] Example 4:

[0116] The present invention also provides a computer-readable storage medium storing computer program code, which, when executed on a computer, causes the computer to perform the aforementioned method steps to implement the impedance matching method for a multi-band series resonant high-voltage test device provided in the above embodiments.

[0117] Example 5:

[0118] The present invention also provides a computer program product that, when run on a computer, causes the computer to perform the above-mentioned related steps to implement the impedance matching method of a multi-band series resonant high voltage test device provided in the above embodiments.

[0119] In this embodiment, the device, computer-readable storage medium, computer program product, or chip are all used to execute the corresponding methods provided above. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0120] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0121] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. An impedance matching method for a multi-band series resonant high-voltage test device, characterized in that, The method includes the following steps: Perform multi-band frequency sweep test on the device under test to obtain the current amplitude-frequency curve of the device under test and each frequency band under test in the current amplitude-frequency curve; For each frequency band to be tested, a predetermined number of fine scans are performed. The target fine scan for each frequency band to be tested is determined based on the peak points in each fine scan. Based on the similarity of each peak point in the target fine scan of each frequency band to be tested with the peak points in other fine scans in terms of frequency, peak width, and amplitude, as well as the size and symmetry of the peak width, the reference degree of each peak point in the target fine scan is obtained, and then the true resonant points in each frequency band to be tested are selected. Adjust the load of the device under test, and based on the reference degree and quality factor of each real resonant point under different loads, as well as the change in amplitude, obtain the degree of dominance of each real resonant point, and then distinguish the main resonant point from the local resonant point; Impedance matching is performed based on the frequency corresponding to the main resonant point. After impedance matching, the device under test is subjected to a voltage boost test with a preset step size. The insulation performance of the device under test is evaluated based on the degree of dominance of the main resonant point and the change in the degree of dominance after each voltage boost, as well as the increase in the number of local resonant points. The method for obtaining the peak width is as follows: For any specified fine scan of any frequency band to be measured, the mean value of the current amplitude corresponding to all frequencies except for all peak points and one adjacent frequency point in the specified fine scan is obtained as the current segmentation value of the specified fine scan. For any peak point in the current amplitude-frequency curve corresponding to the specified fine scan, frequency points are searched one by one from the peak point towards the low frequency direction. When the first point with a current amplitude less than or equal to the current division value is found, it is taken as the target point to the left of the peak point. From the peak point, frequency points are searched one by one in the high-frequency direction. When the first point with a current amplitude less than or equal to the current division value is found, it is taken as the target point to the right of the peak point. The length of the frequency band formed by the frequencies corresponding to the left and right target points is taken as the peak width of the peak point.

2. The impedance matching method for a multi-band series resonant high-voltage test device as described in claim 1, characterized in that, The method for obtaining the target fine scan is as follows: For any frequency band to be tested, the number of peak points of the frequency band to be tested in each specified fine scan is obtained and used as the reference number; The specified fine scan corresponding to the largest reference quantity is taken as the target fine scan for the frequency band under test.

3. The impedance matching method for a multi-band series resonant high-voltage test device as described in claim 1, characterized in that, The method for obtaining the reference level is as follows: For any frequency band to be measured, all other fine scans other than the target fine scan of the frequency band to be measured shall be used as reference fine scans of the frequency band to be measured, and the peak points in the current amplitude-frequency curves corresponding to each reference fine scan shall be used as reference peak points. For any peak point in the fine scan of the target frequency band under test and any reference peak point in any reference fine scan, the result of normalizing the difference between the frequency corresponding to the peak point and the reference peak point is used as the first analysis value. The result of normalizing the difference in peak width between the peak point and the reference peak point is used as the second analytical value. The result of normalizing the difference in amplitude between the peak point and the reference peak point is used as the third analysis value. The sum of the first, second, and third analytical values, followed by negative correlation and normalization, is used as the degree of matching between the peak point and the reference peak point. The degree of matching between this peak point and each reference peak point in the reference fine scan is obtained, and each of these is used as a reference matching degree; When the maximum reference matching degree is greater than the preset matching degree threshold, the reference peak point corresponding to the maximum reference matching degree is taken as the matching peak point of that peak point in the reference fine scan. When the maximum reference matching degree is less than or equal to the preset matching degree threshold, there is no matching peak point in the reference fine scan; The average of the reference matching degree between the peak point and each of its matching peak points is obtained and used as the matching analysis value of the peak point; The result of negatively correlating the absolute values ​​of the tangent slopes corresponding to the target points to the left and right of the peak point is used as the degree of symmetry of the peak point. The result of normalizing the product of the peak width, symmetry, matching analysis value, and number of matching peak points of the peak point is used as the reference level of the peak point.

4. The impedance matching method for a multi-band series resonant high-voltage test device as described in claim 1, characterized in that, The method for obtaining the actual resonant point is as follows: When the reference level is greater than the preset reference level threshold, the corresponding peak point is taken as the true resonant point.

5. The impedance matching method for a multi-band series resonant high-voltage test device as described in claim 1, characterized in that, The method for obtaining the degree of importance is as follows: Adjust the load of the device under test in the specified order, and obtain the reference level, quality factor and corresponding amplitude of each true resonant point after each load adjustment; For any true resonant point, the amplitude corresponding to each load adjustment at the true resonant point is arranged according to the load adjustment order to obtain the amplitude sequence of the true resonant point. The difference between each amplitude in the amplitude sequence and its previous adjacent amplitude is taken as the first difference; The mean and standard deviation of the first difference are added together, negatively correlated, and normalized. This result is taken as the first principal analytical value of the true resonance point. The average of the reference level after all load adjustments at the true resonant point is taken as the second principal analytical value of the true resonant point. The average quality factor after all load adjustments at the true resonant point is taken as the third principal analytical value of the true resonant point. The normalized product of the first, second, and third principal analytical values ​​of the true resonant point is taken as the degree of principality of the true resonant point.

6. The impedance matching method for a multi-band series resonant high-voltage test device as described in claim 1, characterized in that, The method for obtaining the main resonance point and the local resonance point is as follows: The true resonance point corresponding to the greatest degree of preponderance is taken as the principal resonance point; All real resonant points other than the main resonant point are considered as local resonant points.

7. The impedance matching method for a multi-band series resonant high-voltage test device as described in claim 1, characterized in that, The method for evaluating the insulation performance of the device under test in each voltage boost test is as follows: For any given boost test, the degree of dominance of the main resonance point under that boost test and each boost test prior to that boost test is arranged according to the boost test sequence to obtain a sequence of dominance. The difference between each majority in the majority sequence and its preceding adjacent majority is taken as the second difference; The second difference that is negative is taken as the reference difference. The product of the number of reference differences and the absolute value of the smallest reference difference is negatively correlated and normalized, and the result is taken as the first insulation analysis value of this voltage boost test. The second insulation analysis value for this voltage boost test is obtained by negatively correlating and normalizing the difference between the number of local resonant points in this voltage boost test and the number of local resonant points in the first voltage boost test. The normalized result of the product of the primary degree of this voltage boost test, the first insulation analysis value, and the second insulation analysis value is taken as the insulation degree of this voltage boost test; When the insulation level is less than the preset insulation level threshold, it is determined that the insulation performance of the device under test is abnormal during this voltage boost test. When the insulation level is greater than or equal to the preset insulation level threshold, the insulation performance of the device under test is determined to be normal under this voltage boost test.

8. The impedance matching method for a multi-band series resonant high-voltage test device as described in claim 1, characterized in that, The method for obtaining the frequency band to be tested is as follows: For any maximum point in the current amplitude-frequency curve, a continuous frequency band is formed by extending a preset length to both sides of the frequency corresponding to the maximum point as a test frequency band.

9. A multi-band series resonant high-voltage testing device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the impedance matching method for a multi-band series resonant high-voltage test device as described in any one of claims 1-8.

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