A power switch failure testing device and testing method

Abstract

The present application relates to the technical field of switch fault test, and especially relates to a power switch fault test device and a test method. The method comprises the following steps: deploying a switch multiplexing test fixture; controlling the switch multiplexing test fixture to perform contact current pulse excitation test on a power switch to be tested, and synchronously collecting contact group pulse response data; performing contact abnormal jump event evaluation, contact resistance fluctuation rate analysis and contact magnetic field abnormal mode analysis according to the contact group pulse response data; and then performing single-contact fault type analysis according to the contact magnetic field abnormal mode, the contact resistance fluctuation rate and the contact jump abnormal event evaluation data, so as to obtain power switch fault data. The present application realizes single-contact level fault detection by performing independent current pulse excitation test on each contact of the power switch.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of switch fault testing, in particular to a power switch fault testing device and testing method. BACKGROUND

[0002] As a core basic component in power electronic systems, power transmission and distribution networks, industrial automation control and various electronic devices, power switches bear the key task of turning on, carrying and breaking circuit current. In high-voltage and high-current application scenarios, such as power circuit breakers, high-power contactors, heavy-load relays, etc., in order to improve the current-carrying capacity, reduce the single contact temperature rise and electrical wear, enhance the breaking performance and improve the overall reliability, the design structure of multiple contacts in parallel is often used. In this structure, multiple independent moving and stationary contacts are connected in parallel to jointly undertake the task of turning on and off the load current. Ideally, each parallel contact should act synchronously, share the current evenly, and maintain a low and consistent contact resistance. However, traditional power switch testing methods, such as simple on-off test, static contact resistance measurement (e.g. using micro-ohmmeter), insulation resistance test, voltage withstand test, action time measurement (closing time, opening time, different phase of closing and opening, etc.) and temperature rise test under rated load, etc., although can reflect the basic performance and some fault modes of the switch to some extent, cannot realize fine fault testing of each independent contact, and it is difficult to distinguish between normal current fluctuation and abnormal contact jump phenomenon. SUMMARY

[0003] Therefore, the present application provides a power switch fault testing device and testing method to solve at least one of the above technical problems.

[0004] To achieve the above-mentioned purpose, a power switch fault testing method comprises the following steps:

[0005] Step S1: deploying a switch multiplexing test fixture to the power switch to be tested; performing contact pulse signal processing on the power switch to be tested to generate an independent contact pulse excitation sequence; controlling the switch multiplexing test fixture through the independent contact pulse excitation sequence, and performing contact current pulse excitation test on the power switch to be tested to synchronously collect contact group pulse response data;

[0006] Step S2: performing contact excitation current aggregation according to the contact group pulse response data to obtain each contact shunt data; performing contact jump feature analysis according to the contact shunt data to obtain contact jump feature data;

[0007] Step S3: performing contact abnormal jump event evaluation according to the contact jump feature data to generate each contact jump abnormal event evaluation data;

[0008] Step S4: contact resistance fluctuation rate analysis is performed according to the contact group pulse response data, and contact resistance fluctuation rate is generated;

[0009] Step S5: abnormal contact magnetic field analysis is performed based on the contact group pulse response data, and a contact magnetic field abnormal mode is obtained; single contact fault type analysis is performed according to the contact magnetic field abnormal mode, the contact resistance fluctuation rate, and each contact jump abnormal event evaluation data, to obtain power switch fault data.

[0010] The present application realizes independent excitation and response measurement of each parallel contact in the power switch by introducing a multiplexing test fixture and contact pulse signal processing, breaking through the limitation of traditional test methods that can only perform overall evaluation and cannot accurately quantify the state of a single contact. Compared with traditional on-off test, static contact resistance measurement and voltage resistance test, etc., the present application can dynamically test each contact in the process of contact action in the form of pulse excitation, thereby obtaining its independent pulse response characteristics, and further improving the detection ability of current distribution between contacts, dynamic jump characteristics and micro-fault signs. Through aggregated analysis of the pulse response data of the contact group, not only can the shunt of each contact be quantified, but also the abnormal current distribution problems caused by potential contact poor contact, oxidation or mechanical wear, etc. can be detected. Based on the evaluation of the contact jump characteristics, the abnormal jump events of a single contact at the opening and closing moments can be further identified, so that early faults affecting the reliability of the switch can be found in advance. At the same time, the fluctuation rate analysis of the contact resistance can effectively represent the stability of the contact state, avoiding the problem that the traditional static resistance measurement cannot reflect the dynamic contact quality of the contact, and improving the identification accuracy of the contact aging, ablation and other faults. In addition, the present application combines abnormal contact magnetic field analysis, which can identify phenomena such as unstable contact, welding or local arc discharge through electromagnetic characteristic changes, further expanding the detectable range of fault types. Finally, by fusing the contact magnetic field abnormal mode, the contact resistance fluctuation rate and the jump abnormal event evaluation data, fine fault type analysis at the single contact level is realized, breaking through the limitation of traditional methods that can only perform overall discrimination, and improving the fault detection precision and diagnosis ability of the multi-contact parallel power switch. Therefore, the power switch fault test method of the present application realizes effective detection and accurate diagnosis of deep, dynamic, early and implicit faults of the single contact level of the multi-contact parallel power switch through fine pulse excitation and response monitoring, dynamic current distribution analysis, micro-jump characteristic evaluation, dynamic resistance stability consideration and multi-source information fusion diagnosis, greatly improving the comprehensiveness, sensitivity and accuracy of the test.

[0011] Preferably, the step S1 includes:

[0012] The switch multiplexing test fixture is constructed, wherein the switch multiplexing test fixture comprises a programmable current source, a high-speed multiplexer, a data acquisition card, a current probe and a magnetic field sensor;

[0013] An output signal end of the current probe is electrically connected to a group of input channels of the high-speed multiplexer; an output signal of the magnetic field sensor is electrically connected to another group of input channels of the high-speed multiplexer; an output channel of the high-speed multiplexer is electrically connected to the data acquisition card; the data acquisition card is connected to a terminal device through a wireless network;

[0014] The input end of the power switch to be tested is electrically connected to the programmable current source,

[0015] The output end of each contact of the power switch to be tested is clamped by the current probe in contact, and a corresponding magnetic field sensor is placed near each current probe, so that the switch multiplexing test fixture is deployed for the target power switch.

[0016] The switch multiplexing test fixture constructed by the application integrates key components such as a programmable current source, a high-speed multiplexer, a data acquisition card, a current probe and a magnetic field sensor, and constructs a complete and controllable dynamic test platform. The programmable current source can provide accurate contact pulse excitation, ensuring the quality and repeatability of the test signal. By clamping the output end of each contact of the power switch to be tested by the current probe in contact and configuring a corresponding magnetic field sensor for each contact, the current pulse response of each contact and the magnetic field information around each contact can be directly and independently obtained, avoiding the problem of signal aliasing of multiple contacts in the traditional method, and providing raw data support for subsequent accurate single-contact shunt data calculation and magnetic field anomaly analysis. This independent monitoring method for each contact enables in-depth understanding of the actual working state of each contact, thereby discovering local problems hidden under the overall performance.

[0017] Preferably, the contact pulse signal processing of the power switch to be tested in step S1 comprises:

[0018] The switch rated current and the number of contacts are extracted according to the power switch to be tested;

[0019] The current pulse amplitude of each contact is set based on the switch rated current and the number of contacts;

[0020] The duration and interval time of the safety test current pulse are processed based on the current pulse amplitude, and the test pulse duration and interval time are obtained;

[0021] The current pulse sub-sequence is processed according to the contact current pulse amplitude, the test pulse duration and interval time, and then the contact pulse signal is sorted to generate an independent contact pulse excitation sequence.

[0022] The application sets the current pulse amplitude of each contact reasonably according to the rated current and the number of contacts of the switch. This parameterized setting method can ensure that the applied excitation signal can effectively stimulate the electrical characteristics of the contacts and will not cause potential damage to the switch due to excessive current impact, embodying the unity of safety and effectiveness of the test. By considering the requirements of the safety test current pulse, reasonably setting the duty cycle and repetition frequency of the pulse, it can avoid overheating or other unintended effects of the contacts caused by long-time or high-frequency excitation, and ensure the stability of the test process and the reliability of the data. By processing the current pulse sub-sequence of the current pulse amplitude, test pulse duration and interval time, and sorting the contact pulse signals, the final independent contact pulse excitation sequence is generated, realizing the accurate and controllable excitation of each contact. This way of customizing independent excitation sequence for each contact can avoid mutual interference caused by simultaneous action of all contacts when testing multi-contact parallel switch, so as to obtain the response characteristics of a single contact more clearly. The ordered pulse excitation sequence also provides a time reference for subsequent data analysis, facilitating the differentiation and correlation of response signals of different contacts.

[0023] Preferably, the step S1 of controlling the switch multiplexing test fixture by the independent contact pulse excitation sequence and exciting the test power switch by the contact current pulse includes:

[0024] The terminal device sends the independent contact pulse excitation sequence to the switch multiplexing test fixture for control signal coding to obtain a pulse excitation control signal;

[0025] The test state of the switch multiplexing test fixture is judged to obtain a test state flag;

[0026] The test state flag is used to control the switch multiplexing test fixture for contact current pulse excitation test by the pulse excitation control signal, and the current probe, magnetic field sensor and switch power voltage of each contact are synchronously controlled for signal acquisition, to obtain the excitation current signal of each contact, the electromagnetic signal of each contact and the power voltage signal, respectively;

[0027] The excitation current signal of each contact, the electromagnetic signal of each contact and the power voltage signal are transmitted to the terminal device, and then digital signal conversion is performed to obtain the contact group pulse response data.

[0028] The independent contact pulse excitation sequence generated by the terminal device is sent to the switch multiplexing test fixture, and the control signal coding is performed, so that the excitation signal can be accurately recognized and executed by the test fixture, and reliable transmission of the test instruction is realized. Before the excitation test is performed, the test state of the switch multiplexing test fixture is judged, so that the test error or damage caused by abnormal equipment state can be effectively avoided, and the safety and reliability of the test process are ensured. Based on the test state flag, the pulse excitation control signal is used to accurately control the test fixture to apply current pulse excitation to each contact of the power switch, so that independent and orderly excitation of each contact is realized. While the contact current pulse excitation is performed, the current probe, the magnetic field sensor and the switch power voltage of each contact are synchronously controlled for signal acquisition, and the excitation current signal, the electromagnetic signal and the power voltage signal of each contact are acquired respectively.

[0029] Preferably, step S2 comprises the following steps:

[0030] Step S21: performing current calibration processing on each contact according to the excitation current signal of each contact in the contact group pulse response data, to obtain calibrated current data of each contact;

[0031] Step S22: performing contact excitation current aggregation on the calibrated current data of each contact, to obtain shunt data of each contact;

[0032] Step S23: calculating the current change rate of each contact according to the shunt data of each contact, to generate a current change rate curve of each contact;

[0033] Step S24: identifying a jump edge interval according to the current change rate curve of each contact, to obtain jump edge interval data of each contact; wherein the jump edge interval identification comprises rising edge identification, steady state segment identification and falling edge identification;

[0034] Step S25: calculating the maximum jump rate of each contact according to the jump edge interval data of each contact;

[0035] Step S26: calculating the jump time of each contact according to the jump edge interval data of each contact;

[0036] Step S27: extracting the jump edge jitter value of each contact from the current change rate curve of each contact based on the jump edge interval data of each contact;

[0037] Step S28: combining the maximum jump rate of each contact, the jump time of each contact and the jump edge jitter value of each contact to obtain contact jump feature data.

[0038] The application calibrates the contact excitation current signal, effectively eliminates sensor errors and system deviations, aggregates the contact excitation current, directly obtains the instantaneous shunt current data of each contact, clearly reveals the specific situation of current distribution between parallel contacts, and quantifies the current imbalance. By calculating the current change rate of each contact and generating the corresponding curve, the scheme can more carefully observe the dynamic response of the contact in the on-off process. Based on these current change rate curves, the scheme can accurately identify the jump edge interval, including the rising edge, steady state segment and falling edge, so as to divide the contact action process into more detailed stages for analysis. This fine interval division provides an accurate time reference for subsequent calculation of the maximum jump rate and jump time. The calculation of the maximum jump rate and jump time of each contact directly reflects the rapidity and synchronicity of the contact action, which is a key indicator for evaluating the performance of the contact mechanism, and can effectively identify mechanical failures such as slow action and jamming. The jitter of the jump edge is usually related to unstable factors in the contact process, such as slight vibration of the contact surface, foreign matter intervention, etc., which is a potential representation of early contact failure and mechanism loosening. Quantifying the jitter of the jump edge can more sensitively capture these subtle abnormal phenomena.

[0039] Preferably, step S3 comprises the following steps:

[0040] Step S31: determining whether each contact has a jump too fast or too slow event according to the maximum jump rate of each contact, to obtain a rate abnormality flag of each contact; wherein when the maximum jump rate of the contact exceeds 500A / s or is lower than 50A / s, it is determined that the contact has a jump rate abnormality;

[0041] Step S32: determining whether each contact has a jump timeout or too short event according to the maximum jump rate of each contact, to obtain a time abnormality flag of each contact; wherein when the jump duration of the contact exceeds 5ms or is lower than 0.5ms, it is determined that the contact has a jump time abnormality;

[0042] Step S33: determining whether each contact has a jump jitter abnormality event by a preset jitter threshold value for the jump edge jitter value of each contact, to obtain a jitter abnormality flag of each contact; wherein when the jump time deviation between adjacent two pulses of the contact jump edge exceeds 15%, it is determined that the contact has a jump jitter abnormality;

[0043] Step S34: performing comprehensive evaluation of the contact abnormal jump event based on the rate abnormality flag of each contact, the time abnormality flag of each contact and the jitter abnormality flag of each contact, to generate jump abnormality event evaluation data of each contact; wherein when a certain contact simultaneously satisfies the conditions of any two or more abnormality flags, or the same type of abnormality flag appears at least 5 times in 10 consecutive tests of the contact, it is determined that the contact has a serious jump abnormality event.

[0044] The application can quickly identify the abnormal events of the contact action speed by presetting the rate threshold (too fast or too slow) to judge the maximum jump rate of each contact, which is often related to the problems of contact mechanism blocking, poor lubrication or insufficient driving force, etc. The preset time threshold (timeout or too short) is used to evaluate the jump time of each contact, which can effectively detect the abnormal events of contact action time, such as contact opening and closing delay, rapid disconnection caused by poor contact, etc. These time abnormalities directly reflect the potential problems of contact mechanism or electrical circuit. The jump edge jitter value analysis based on the preset jitter threshold is introduced to judge whether there is a jump jitter abnormal event. By quantifying the deviation of the jump time between adjacent pulses, the instability of the contact during the action process can be sensitively captured, such as the slight separation and coincidence of the contact surface, the loosening of the mechanism parts, etc. Based on the rate abnormality flag, the time abnormality flag and the jitter abnormality flag, a more strict serious jump abnormal event judgment condition is set, such as meeting multiple abnormal flags at the same time or frequently appearing the same type of abnormality in multiple tests, which can effectively exclude the interference of accidental factors, improve the reliability of fault judgment, and distinguish different severity of abnormal events.

[0045] Preferably, step S4 comprises the following steps:

[0046] Step S41: Calculate the total current of the switch according to the shunt data of each contact;

[0047] Step S42: Calculate the equivalent total resistance of the total current of the switch by the power voltage signal in the group pulse response data of the contact, and generate the equivalent total resistance data;

[0048] Step S43: Perform iterative distribution of the instantaneous contact resistance of the contact based on the equivalent total resistance data and the shunt data of each contact, and obtain the instantaneous resistance sequence of each contact;

[0049] Step S44: Calculate the average resistance of each contact according to the instantaneous resistance sequence of each contact;

[0050] Step S45: Calculate the standard deviation of the resistance of each contact according to the instantaneous resistance sequence of each contact and the average resistance;

[0051] Step S46: Calculate the resistance fluctuation rate of each contact in the power switch to be tested based on the average resistance and the standard deviation of the resistance of each contact, and generate the contact resistance fluctuation rate.

[0052] The application obtains the total current of the switch by aggregating the shunt data of each contact, and combines the synchronously collected power voltage signal, adopts the iterative distribution method of contact instantaneous contact resistance, and calculates the instantaneous resistance sequence of each contact based on the equivalent total resistance and the shunt data of each contact, so that the resistance change of the contact under the current pulse excitation can be reflected, and the average contact resistance level and the fluctuation degree of each contact are quantified. The average value reflects the overall conductivity of the contact, and the standard deviation represents the stability of the contact resistance. Based on the calculated average value and standard deviation of the resistance, the resistance fluctuation rate is a comprehensive index, which reflects the change degree of the contact resistance relative to the average value, and can effectively evaluate the stability and reliability of the contact, and a higher resistance fluctuation rate usually means that the contact is unstable, and there are problems such as oxidation, pollution and looseness of the contact surface, which will affect the conductivity and long-term reliability of the switch.

[0053] Preferably, step S5 comprises the following steps:

[0054] Step S51: grouping the abnormal contacts of the to-be-tested power switch through the abnormal contact grouping of each contact jump event evaluation data, to obtain the abnormal contact group of the switch;

[0055] Step S52: performing abnormal contact magnetic field analysis on the abnormal contact group of the switch through the electromagnetic signal of each contact in the contact group pulse response data, to obtain the contact magnetic field abnormal mode;

[0056] Step S53: performing single-contact fault type rule matching based on the contact magnetic field abnormal mode, the contact resistance fluctuation rate and the jump abnormal event evaluation data of each contact, to generate single-contact fault type data;

[0057] Step S54: performing health degree evaluation on the to-be-tested power switch through the single-contact fault type data, and then performing overall fault type processing and fault positioning of the switch, to obtain the fault data of the power switch.

[0058] The application groups the contacts of the measured power switch by using the previously generated jump abnormal event evaluation data of each contact, identifies the abnormal contacts, effectively focuses on the target of fault analysis, and improves the efficiency. For the identified abnormal contact group, the electromagnetic signal of each contact in the contact group pulse response data is used for in-depth abnormal contact magnetic field analysis, and the magnetic field information can reflect the local characteristics of the contact current distribution and the potential physical structure abnormality. Comprehensive analysis of the contact magnetic field abnormal mode, the contact resistance fluctuation rate and the jump abnormal event evaluation data of each contact can more comprehensively and accurately judge the specific fault type of each abnormal contact, such as mechanism failure (such as slow action and jitter), contact failure (such as excessive and unstable contact resistance), or electromagnetic abnormality, and perform overall health degree evaluation on the to-be-tested power switch, to realize the automation and intelligentization of fault diagnosis.

[0059] Preferably, step S52 is specifically:

[0060] According to the electromagnetic signals of each contact in the contact group impulse response data, three-axis orthogonal direction magnetic field intensity processing is performed to obtain contact three-axis magnetic field intensity data;

[0061] The spatial position of the magnetic sensor is obtained, and the spatial position of the magnetic sensor is spatially mapped with the contact three-axis magnetic field intensity data, and then magnetic field gradient calculation is performed to obtain magnetic field gradient distribution data;

[0062] According to the magnetic field gradient distribution data, the gradient vector modulus value is calculated, and then the maximum vector modulus value position is extracted to obtain the maximum magnetic field gradient data;

[0063] The magnetic field center offset of the abnormal contact group is analyzed by the magnetic field gradient distribution data to obtain the abnormal contact magnetic field offset;

[0064] According to the maximum magnetic field gradient data, the abnormal contact magnetic field offset, and the magnetic field gradient distribution data, the contact magnetic field abnormal mode processing is performed to obtain the contact magnetic field abnormal mode.

[0065] The present application processes the three-axis orthogonal direction magnetic field intensity of each contact electromagnetic signal, captures the magnetic field intensity of three orthogonal directions, can more comprehensively reflect the magnetic field distribution around the contact, combines the spatial position information of the magnetic sensor, spatially maps the magnetic field intensity data, and calculates the magnetic field gradient distribution data, which can more sensitively reveal the local abnormality of the current path, such as current contraction or diffusion caused by poor contact of the contact. Calculate the magnetic field gradient distribution. Calculate the gradient vector modulus value and extract the maximum value and its position, the maximum magnetic field gradient and its position usually indicate the area where the current density changes most sharply, which is the key part of the fault. Under ideal conditions, the magnetic field center around the contact should be aligned with the physical center of the contact; when the contact occurs poor contact or uneven current distribution, the magnetic field center will be offset. The size and direction of the magnetic field offset can reflect the nature and degree of the fault. Considering the maximum magnetic field gradient data, the abnormal contact magnetic field offset, and the overall magnetic field gradient distribution data, the contact magnetic field abnormal mode processing can identify a variety of magnetic field abnormal modes, such as abnormal increase or decrease of magnetic field intensity, uneven magnetic field gradient distribution, magnetic field center offset, etc. These modes are associated with specific contact fault types (such as increased contact resistance, reduced contact area, changed current path, etc.).

[0066] Preferably, the present application also provides a power switch fault testing device, comprising a control system for executing the power switch fault testing method as described above, the control system comprising:

[0067] The switch pulse test module is used to deploy a switch multiplexing test fixture for the power switch to be tested; process the contact pulse signal of the power switch to be tested to generate an independent contact pulse excitation sequence; control the switch multiplexing test fixture to perform contact current pulse excitation testing on the power switch to be tested through the independent contact pulse excitation sequence, and simultaneously collect contact group pulse response data;

[0068] The contact feature analysis module is used to aggregate the contact excitation current according to the contact group pulse response data to obtain the shunt data of each contact; and to perform contact jump feature analysis according to the shunt data of each contact to obtain the contact jump feature data;

[0069] The contact abnormal jump evaluation module is used to evaluate the contact abnormal jump event based on the contact jump characteristic data and generate evaluation data of each contact abnormal jump event;

[0070] Resistance fluctuation analysis module, used to analyze contact resistance fluctuation rate based on contact group pulse response data and generate contact resistance fluctuation rate;

[0071] The comprehensive fault diagnosis module is used to analyze abnormal contact magnetic fields based on the contact group pulse response data to obtain the contact magnetic field abnormality pattern; and to analyze the single contact fault type based on the contact magnetic field abnormality pattern, contact resistance fluctuation rate, and each contact jump abnormal event evaluation data to obtain the power switch fault data. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 This is a schematic flow chart of the steps of the power switch fault testing method of the present invention;

[0073] Figure 2 for Figure 1 Detailed implementation steps of step S5;

[0074] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0075] The following is a clear and complete description of the technical method of the present invention in conjunction with the accompanying drawings. It is obvious that the embodiments described are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts are within the scope of protection of the present invention.

[0076] Furthermore, the accompanying drawings are included to provide a further understanding of the present application, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In the drawings:

[0077] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Pronouns in the masculine form include the feminine form, and vice versa, and the singular form also includes the plural form, unless the context clearly dictates otherwise. Pronouns in the plural form include the singular form, unless the context clearly dictates otherwise. The term "and / or" includes any and all combinations of one or more of the associated listed items. The term "at least one of' includes any and all combinations of one or more of the associated listed items.

[0078] To achieve the above object, there is provided Figures 1 to 2 The present application provides a power switch fault test method, comprising the following steps:

[0079] Step S1: deploying a switch multiplexing test fixture to the power switch to be tested; performing contact pulse signal processing on the power switch to be tested to generate an independent contact pulse excitation sequence; controlling the switch multiplexing test fixture through the independent contact pulse excitation sequence, and performing contact current pulse excitation test on the power switch to be tested to synchronously collect contact group pulse response data;

[0080] Step S2: performing contact excitation current aggregation according to the contact group pulse response data to obtain contact shunt data; performing contact jump characteristic analysis according to the contact shunt data to obtain contact jump characteristic data;

[0081] Step S3: performing contact abnormal jump event evaluation according to the contact jump characteristic data to generate contact jump abnormal event evaluation data;

[0082] Step S4: performing contact resistance fluctuation rate analysis according to the contact group pulse response data to generate contact resistance fluctuation rate;

[0083] Step S5: performing abnormal contact magnetic field analysis based on the contact group pulse response data to obtain contact magnetic field abnormal mode; performing single contact fault type analysis according to the contact magnetic field abnormal mode, the contact resistance fluctuation rate, and the contact jump abnormal event evaluation data to obtain power switch fault data.

[0084] The power switch fault test method comprises the following steps:

[0085] Step S1: deploying a switch multiplexing test fixture on the power switch to be tested; performing contact pulse signal processing on the power switch to be tested to generate an independent contact pulse excitation sequence; controlling the switch multiplexing test fixture through the independent contact pulse excitation sequence, and performing contact current pulse excitation test on the power switch to be tested to synchronously collect contact group pulse response data;

[0086] In one embodiment of the present invention, a switch multiplexing test fixture is constructed. The fixture includes a programmable DC current source (range 0-10A, accuracy 0.1mA), an 8-channel high-speed multiplexer (switching speed <10ns), a 4-channel high-precision data acquisition card (sampling rate 1MS / s), two current probes with a bandwidth of 50MHz (range 0-5A, accuracy 1mA), and two miniature three-axis magnetic field sensors (range ±2mT, resolution 0.1mT). The output signals of current probes 1 and 2 are connected to channels 1 and 2 of the high-speed multiplexer, respectively; the X, Y, and Z axis output signals of magnetic field sensors 1 and 2 are connected to channels 3-5 and channels 6-8 of the high-speed multiplexer, respectively; the output of the high-speed multiplexer is connected to channel 1 of the data acquisition card; and the data acquisition card is connected to a terminal device equipped with a test control and data analysis program via Wi-Fi. The common input of the power switch to be tested is then connected to the positive and negative terminals of the programmable current source, and the current direction is set. Use current probe 1 to clamp the output leads of contact A, and current probe 2 to clamp the output leads of contact B. Magnetic field sensor 1 is fixed near current probe 1, with its sensitive axis roughly aligned with the direction of current flow through contact A. Similarly, magnetic field sensor 2 is fixed near current probe 2, with its sensitive axis roughly aligned with the direction of current flow through contact B. To process the contact pulse signals, the terminal device sets the current pulse amplitude for each contact to 80% of the rated current, or 4A, based on the power switch's rated current of 5A and the number of two output contacts. Based on this amplitude and taking into account the power switch's heat dissipation characteristics, the test pulse duration is set to 5ms, with an interval of 50ms. Ten current pulse subsequences containing identical pulse parameters are generated for contacts A and B, respectively. When sequencing the contact pulse signals, an alternating excitation strategy is employed: the path of contact A is stimulated 10 times, followed by the path of contact B, generating a separate contact pulse excitation sequence containing 20 pulses. The terminal device sends this excitation sequence to the test fixture via Wi, controls the programmable current source to output current pulses according to the set timing and parameters, and synchronously collects the excitation current signals of contacts A and B (through current probes), three-axis electromagnetic signals (through magnetic field sensors), and the voltage signal at the power input end through a high-speed multiplexer and a data acquisition card to obtain the contact group pulse response data containing current, magnetic field, and voltage time series.

[0087] Step S2: performing contact excitation current aggregation based on the contact group pulse response data to obtain the shunt data of each contact; performing contact jump characteristic analysis based on the shunt data of each contact to obtain the contact jump characteristic data;

[0088] In the embodiment of the present application, for example, taking a single-pole double-throw power switch as an example, including but not limited to a single-pole double-throw power switch, since the power switch is a single-pole double-throw, only one contact is turned on in each excitation test, so the shunt current data of each contact is the excitation current signal of each contact. For example, during the 10 pulses of exciting contact A, the current waveform of contact A is recorded; during the 10 pulses of exciting contact B, the current waveform of contact B is recorded. Then, the current change rate of each contact is calculated based on the current waveform data of each contact, and the current change rate curves of contact A and contact B are obtained. According to these curves, the rising edge, steady state section and falling edge section of each pulse are identified. For each pulse of each contact, the maximum jump rate of the rising edge and the falling edge, the rising time and the falling time are calculated. Further, for each contact, the deviation of the jump time between consecutive pulses is calculated, and the jump edge jitter value of each contact is obtained. Finally, the maximum jump rate, the jump time and the jump edge jitter value of each contact are combined to form the contact jump feature data of contact A and contact B respectively.

[0089] Step S3: evaluating the abnormal jump event of each contact according to the contact jump feature data, and generating the abnormal jump event evaluation data of each contact;

[0090] In the embodiment of the present application, the abnormal jump event of each contact is evaluated. For each pulse of contact A, it is judged whether the maximum jump rate of the rising edge exceeds 500A / s or is lower than 50A / s, if it exceeds, it is marked as a fast / slow rate abnormal flag. It is judged whether the rising time exceeds 5ms or is lower than 0.5ms, if it exceeds, it is marked as a time-out / short abnormal flag. It is compared whether the rising time deviation of the two consecutive pulses of contact A exceeds 15%, if it exceeds, it is marked as a jitter abnormal flag. The same judgment is made for contact B. For example, if the rising time of a certain pulse of contact A is 6ms, it is marked as a time-out abnormal flag. If the maximum jump rate of the rising edge of contact B is lower than 40A / s for 6 times in 10 consecutive tests, it is marked that contact B has a slow jump rate abnormality (satisfying the condition of continuous multiple abnormalities). The abnormal flags of each contact are comprehensively analyzed. For example, if contact A has both slow jump and jitter abnormal flags in a test, it is determined that contact A has a serious jump abnormal event, and the event is recorded.

[0091] Step S4: analyzing the contact resistance fluctuation rate according to the contact group pulse response data, and generating the contact resistance fluctuation rate;

[0092] In the embodiment of the present application, the equivalent total resistance of the power switch in each excitation process is calculated by using the power supply voltage and the total current. Since it is a single-pole double-throw switch, only one contact is turned on each time, so the equivalent total resistance is approximately equal to the resistance of the turned-on contact. For each excitation of contact A, the instantaneous resistance sequence of contact A is obtained; for each excitation of contact B, the instantaneous resistance sequence of contact B is obtained. Then, the resistance average of the instantaneous resistance sequence of contact A and contact B is calculated respectively. Further, the resistance standard deviation of the instantaneous resistance sequence of contact A and contact B is calculated. Finally, the contact resistance fluctuation rate of contact A and contact B is obtained by dividing the resistance standard deviation of contact A and contact B by the resistance average of contact A and contact B respectively.

[0093] Step S5: Abnormal contact magnetic field analysis is performed based on the contact group impulse response data to obtain a contact magnetic field anomaly pattern; single contact fault type analysis is performed according to the contact magnetic field anomaly pattern, the contact resistance fluctuation rate, and the evaluation data of each contact jump anomaly event to obtain power switch fault data.

[0094] In the embodiment of the present application, it is assumed that contact B is identified as having a serious jump slow anomaly, and the three-axis electromagnetic signals corresponding to contact B collected in step S1 are analyzed. The three-axis magnetic field intensity data of contact B in each excitation process is calculated, and the magnetic field gradient calculation is performed to obtain the magnetic field gradient distribution data. The gradient vector modulus value is calculated, and the maximum vector modulus value position is extracted to obtain the maximum magnetic field gradient data. The offset of the magnetic field center of contact B relative to its physical position is analyzed to obtain the magnetic field offset of the abnormal contact B. In combination with the maximum magnetic field gradient data of contact B, the magnetic field offset, and the overall morphology of the magnetic field gradient distribution, it is determined whether there is a specific magnetic field anomaly pattern, such as weak magnetic field intensity, slow magnetic field signal rise, etc. Then, the magnetic field anomaly pattern of contact B, the resistance fluctuation rate (for example, 0.6) of contact B obtained in step S4, and the jump slow anomaly evaluation data obtained in step S3 are matched with the preset fault rules. For example, if there is a rule of “jump slow + weak magnetic field intensity + high resistance fluctuation rate -> poor contact (oxidation)” in the rule library, it is determined that the fault type of contact B is poor contact (oxidation). If contact A is evaluated as normal in step S3, the fault type of contact A is “no fault”. Finally, the fault types of contact A and contact B are summarized to form the fault data of the power switch, for example: “contact A: no fault; contact B: poor contact (oxidation)”. According to the number and type of fault contacts, the health degree evaluation of the power switch is given, for example: “minor fault, please check contact B”.

[0095] Preferably, the deployment of the switch multiplexing test fixture to the power switch to be tested in step S1 comprises:

[0096] A switch multiplexing test fixture is constructed, wherein the switch multiplexing test fixture comprises a programmable current source, a high-speed multiplexer, a data acquisition card, current probes and magnetic field sensors;

[0097] An output signal end of the current probe is electrically connected to a group of input channels of the high-speed multiplexer; an output signal of the magnetic field sensor is electrically connected to another group of input channels of the high-speed multiplexer; an output channel of the high-speed multiplexer is electrically connected to the data acquisition card; the data acquisition card is connected to a terminal device through a wireless network;

[0098] An input end of the power switch to be tested is electrically connected to the programmable current source,

[0099] The output end of each contact of the power switch to be tested is clamped by a current probe in a contact manner, and a corresponding magnetic field sensor is placed near each current probe, so that the switch multiplexing test fixture is deployed for the target power switch.

[0100] In the embodiment of the present application, a DC programmable current source with at least 500A output capability, ripple coefficient less than 0.1%, and remote programming control through standard command set (such as SCPI) is selected. Secondly, a high-speed multiplexer module based on solid-state relay technology, with switching time less than 1 microsecond, and at least 8 differential input channels is selected, such as the module installed in the PXI chassis. At the same time, a multi-channel data acquisition card (DAQ) with 16-bit resolution, sampling rate not less than 1MS / s, and synchronous sampling capability is selected, also installed in the PXI chassis. Prepare several (the number is equal to the number of contacts to be tested, for example 3) open-loop or closed-loop Hall effect current probes with measurement range covering the expected test current and bandwidth not less than 1MHz, and the same number of three-axis magnetic field sensors with sufficient sensitivity to detect the magnetic field transient generated by the on-off current near the switch contact. When assembling, connect the BNC output signal cable of the current probe to channel 1 to channel N (N is the number of contacts) of the high-speed multiplexer through a low-noise coaxial cable. Connect the signal output cable of the magnetic field sensor (usually including X, Y, Z axis signals) to channel N+1 to channel M of the high-speed multiplexer through shielded twisted pair. The common output channel of the high-speed multiplexer is connected to the analog input port AIN0 of the data acquisition card through a high-shielded coaxial cable. The data acquisition card is connected to a preset wireless local area network access point with WPA2 encryption through its integrated wireless network interface module (such as a module supporting the 802.11ac standard). The wireless network is also connected to an industrial tablet or notebook computer running a specific data receiving and analysis program as a terminal device. Select a flexible copper cable with a cross-sectional area sufficient to carry at least 250A current (considering the margin), and an insulation level that meets the test voltage requirements, and crimp a high-conductivity copper nose (wire nose) at both ends of the cable. Check the input terminals (such as marked as L1, L2, L3) of the contactor to be tested and the positive and negative output terminals of the programmable current source to ensure that they are clean and free of oxidation. Using a torque wrench, according to the torque specified by the manufacturer of the contactor and the current source, firmly connect one end of the cable copper nose to the positive output terminal of the programmable current source, and the other end to the L1 input terminal of the contactor to be tested. For a three-phase switch, if the test target is single-phase current carrying capacity or multi-phase independent test, only one phase input is connected; if three-phase load simulation is required, L1, L2, L3 terminals are connected in parallel or series to the current source output (or use a three-phase power supply, but this description is for single current source connection). Connect the other cable of the same specification to the negative (or return) output terminal of the programmable current source, and the other end to the return end of the load circuit matched with the output end of the contactor to be tested or directly to the expected common return end of the contactor, to avoid additional voltage drop and heat generation in subsequent high-current tests.Select the first Hall-effect current probe, open its jaws, and precisely clamp around the wire or busbar connected to the T1 output terminal. When operating, make sure the wire is in the center area of the probe's sensing window, and the jaws are fully closed without any gap, and the probe body does not directly contact the live conductor (depending on the wire insulation). Select the first three-axis magnetic field sensor, and use a non-magnetic, high-temperature-resistant custom fixture or high-strength insulating tape to fix it in a position close to the T1 output terminal contact area, about 5-10 mm away from the contact gap. The specific axis of the sensor (e.g., Z-axis) should be approximately perpendicular to the expected current path or parallel to the contact movement direction, in order to maximize the capture of the magnetic field characteristics generated by switch action and potential electric arcs. Repeat this process to clamp the second current probe around the wire of the T2 output terminal, and fix the second magnetic field sensor near the T2 contact; and clamp the third current probe around the wire of the T3 output terminal, and fix the third magnetic field sensor near the T3 contact. Ensure that each current probe is placed in a one-to-one correspondence with its corresponding magnetic field sensor, forming a one-to-one measurement unit. The signal cables of all sensors should be properly arranged and connected to the corresponding input channels reserved on the high-speed multiplexer earlier. After deployment, check the firmness of all sensor fixings to avoid displacement under the mechanical vibration of switch action.

[0101] Preferably, the contact pulse signal processing of the power switch to be tested in step S1 comprises:

[0102] According to the rated current and the number of contacts of the power switch to be tested, the rated current and the number of contacts of the power switch to be tested are extracted;

[0103] Based on the rated current and the number of contacts, the current pulse amplitude of each contact is set;

[0104] Based on the current pulse amplitude, the duration and interval time of the safety test current pulse are processed by the contact current pulse amplitude, to obtain the test pulse duration and interval time;

[0105] According to the contact current pulse amplitude, the test pulse duration and interval time, the current pulse sub-sequence processing is performed, and then the contact pulse signal sorting is performed to generate an independent contact pulse excitation sequence.

[0106] In the embodiment of the application, the test type is taken as an example of a three-pole molded case circuit breaker. An operator first visually inspects the side or front nameplate of the circuit breaker body. For example, the nameplate clearly indicates "In = 400A", thereby determining that the rated current of the power switch is 400 amperes. At the same time, the wiring terminals of the circuit breaker are observed or the product data manual thereof is consulted to confirm that the circuit breaker has three independent phase line paths, L1, L2 and L3, and therefore has three contacts (without considering auxiliary contacts). According to the obtained rated current (400A) and the number of contacts (3), the test device built-in parameter calculation logic is used to determine the peak value of the test current pulse applied to each contact. The setting logic follows a preset rule: the peak value of the test current applied to each contact is 120% of its rated current. The control unit (for example, a controller based on an embedded processor) of the test device performs this calculation: target pulse amplitude = rated current x 1.20 = 400A x 1.20 = 480A. Since the test target is to evaluate the performance of a single contact or to perform independent excitation between contacts, the pulse amplitude value of 480A is set as the target peak value of the current pulse subsequently applied to each measured contact (T1, T2, T3, usually sequentially applied or controlled through a specific route). Based on the current pulse amplitude set in the previous step, and the thermal characteristic parameters (for example, the allowable temperature rise and thermal time constant of a copper alloy contact) of the contact material obtained from the switch data manual or through pre-experiment, the test control application performs a thermal energy limitation calculation. Using the I²t (current square times time) criterion, the upper limit of the energy of a single pulse injection is set, for example, to limit the instantaneous temperature rise of a single pulse to no more than 10% of the long-term working temperature rise limit of the contact. To meet this temperature rise limitation, the maximum allowed pulse duration is 125 milliseconds. At the same time, in order to ensure that the contact has sufficient time to cool between pulses and avoid heat accumulation, the pulse interval time (2500) is set. The interval time is set according to the average power limitation, for example, the average power of the pulse sequence is required to be no more than 5% of the rated loss power of the switch. A basic "current pulse sub-sequence unit" is defined, which includes a complete pulse event: the current rises from 0A to 480A, maintains for 125ms, and then falls to 0A, followed by a 2500ms current-free interval. Then, the sequence generator module of the test device creates a repeated sub-sequence according to the preset test strategy (for example, 10 pulses are applied to each contact to evaluate its stability). For example, a list containing 10 "current pulse sub-sequence units" is generated to form a "single contact test block". Finally, the contact pulse signals are sorted to generate the final "independent contact pulse excitation sequence". One way of sorting is sequential testing: the "single contact test block" is sequentially assigned to each contact.The specific sequence of instructions is as follows: [(target contact T1, amplitude 480A, duration 125ms, interval 2500ms) repeated 10 times; (target contact T2, amplitude 480A, duration 125ms, interval 2500ms) repeated 10 times; (target contact T3, amplitude 480A, duration 125ms, interval 2500ms) repeated 10 times]. This complete sequence of instructions is formatted into a command list recognizable by the programmable current source and, if any, the output switching matrix, stored in the memory of the test controller, ready to be issued in sequence during the test execution phase to drive the hardware to generate precise, independent pulse excitation for each contact.

[0107] Preferably, the step S1 controls the switch multiplexing test fixture through the independent contact pulse excitation sequence and performs the contact current pulse excitation test on the power switch to be tested:

[0108] The terminal device sends the independent contact pulse excitation sequence to the switch multiplexing test fixture for control signal coding to obtain a pulse excitation control signal;

[0109] The test state of the switch multiplexing test fixture is judged to obtain a test state flag;

[0110] The switch multiplexing test fixture is controlled through the pulse excitation control signal based on the test state flag to perform the contact current pulse excitation test, and the current probe, the magnetic field sensor, and the switch power supply voltage of each contact are synchronously controlled for signal acquisition to respectively obtain the contact excitation current signal, the contact electromagnetic signal, and the power supply voltage signal;

[0111] The contact excitation current signal, the contact electromagnetic signal, and the power supply voltage signal are transmitted to the terminal device, and then digital signal conversion is performed to obtain the contact group pulse response data.

[0112] In the embodiments of the present application, the JSON sequence data packet is sent to the preset IP address and port number of the switch multiplexing test fixture (specifically, the embedded controller in the PXI chassis) using the TCP / IP protocol stack through its wireless network interface (for example, a Wi-Fi module). The firmware or special control logic running on the PXI controller receives the data packet, parses the JSON structure, and extracts the target contact, current amplitude, duration, interval time, and repetition number of each excitation step. Then, the control logic converts these high-level parameters "encoding" into the underlying instruction set for specific hardware. For example, "contact: T1" is converted into a specific register write value or digital I / O signal pattern that configures the high-speed multiplexer to switch to channel 1 and channel (N+1) connected to the T1 sensor. Before executing any high-current pulse, the PXI controller of the test fixture must perform a series of strict self-tests and state confirmations. First, the controller sends a query command to the programmable current source through the PXI backplane or communication bus (such as GPIB, Ethernet) to confirm that the current source has no internal failure, is not in an overheating or overload protection state, and its output is currently in the OFF state. Second, the controller detects the state of the high-speed multiplexer module, confirms that it has correctly responded to the configuration command and has no hardware failure report. Third, the controller checks the state of the data acquisition card (DAQ), confirms that it has passed the self-test, the clock is stable, and the communication with the controller is normal. In addition, the controller also reads the state of the external safety interlock signal connected to its digital input port, such as checking whether the test protection door is closed in place (corresponding input is high level). The controller integrates all these query results and input states: if the current source is normal, the MUX responds, the DAQ is ready, and the safety interlock is closed, then set a Boolean variable or a specific register bit in the internal memory, denoted as "Test_Ready_Flag", with a value of TRUE (or 1). If any of the checks fails, set "Test_Ready_Flag" to FALSE (or 0), and prevent the execution of subsequent pulse excitation, while displaying specific error information on the terminal device interface. Only when the internal "Test_Ready_Flag" is TRUE, the PXI controller starts to execute the previously generated "pulse excitation control signal" sequence. For the first pulse instruction in the sequence (for example, for T1 contact, 480A, 125ms): the controller first sends an instruction to configure the high-speed multiplexer, connecting its output to the current probe corresponding to the T1 contact (for example, channel 1) and the input of the magnetic field sensor (for example, channel N+1).Meanwhile, the controller configures the data acquisition card (DAQ) with a sampling rate of 1 MS / s, sets the acquisition duration (e.g. 200 ms to cover the pre- and post-pulse), specifies the channels to be acquired (MUX output channels, as well as a channel connected to another one for monitoring the power supply voltage, e.g. AIN1), and configures the hardware trigger mechanism (e.g. based on the rising edge of a digital trigger signal from the controller). Then, the controller sends a command to the programmable current source to execute the pulse (e.g. INITiate: IMMediate), and at the same precise moment (or with nanosecond-level synchronization via the PXI backplane trigger bus) sends a digital trigger signal to the DAQ card to start data acquisition. During the 125 ms duration of the current pulse and within the set acquisition window, the DAQ card synchronously digitizes the analog voltages from the MUX (carrying the T1 current probe signal and the magnetic field sensor signal) and the power supply voltage monitoring channel at a rate of 1 MHz, and stores the digitized sample points into its on-board FIFO buffer or the memory of the PXI controller. After the pulse ends, the controller sends a command to turn off the current source output. After the acquisition is completed, the controller reads the data stored by the DAQ to obtain time series arrays of the raw excitation current signal of the T1 contact (from the current probe), the raw electromagnetic signal (from the magnetic field sensor), and the power supply voltage signal. The execution is repeated strictly according to the sequence instructions, a specified number of repetitions are performed for T1, then the MUX configuration is switched to the T2-related channels, and the pulse and acquisition for T2 are performed, until all the pulses for all the contacts are completed. The data packet is sent to the network port listened by the test control application running on the terminal device using the TCP protocol. After receiving the data packet, the application on the terminal device first parses the data of each signal channel according to the metadata. Then, the "digital signal conversion" is performed: the raw integer values (ADC counts) acquired by the DAQ are converted into floating-point values with physical units according to the pre-calibrated sensor sensitivity and the voltage range and gain settings of the DAQ.

[0113] Preferably, step S2 comprises the following steps:

[0114] Step S21: performing current calibration processing for each contact according to the excitation current signal of each contact in the contact group pulse response data, to obtain calibrated current data of each contact;

[0115] Step S22: performing contact excitation current aggregation on the calibrated current data of each contact, to obtain shunt data of each contact;

[0116] Step S23: calculating the current change rate of each contact according to the shunt data of each contact, to generate a current change rate curve of each contact;

[0117] Step S24: identifying the jump edge interval according to the contact current rate of change curve to obtain contact jump edge interval data; wherein, the jump edge interval identification includes rising edge, steady state section and falling edge identification;

[0118] Step S25: calculating the maximum jump rate of each contact according to the contact jump edge interval data;

[0119] Step S26: calculating the contact jump time according to the contact jump edge interval data;

[0120] Step S27: extracting the contact jump edge jitter value of the contact current rate of change curve based on the contact jump edge interval data;

[0121] Step S28: combining the maximum jump rate of each contact, the contact jump time and the contact jump edge jitter value to obtain the contact jump feature data.

[0122] In the embodiment of the present application, from the "contact group impulse response data", the time series array of original current signal collected during all pulse excitations for the first contact (e.g. T1) is extracted. For the current data array of one of the pulses, the silent time period before the actual occurrence of the pulse is determined, for example, according to the 10 millisecond interval before the trigger signal timestamp. The values of all current sampling points in this interval are extracted, and the arithmetic mean of these sampling points is calculated, which is the zero point offset of this measurement. The value of each sampling point in the entire current data array of this pulse is subtracted by the calculated zero point offset. Repeat this zero point calibration process for all the remaining pulses of the T1 contact. Then, in the same way, the independent zero point offset calculation and subtraction calibration are sequentially performed on the current signal of each pulse excitation of the second contact (T2) and the third contact (T3). The final data set obtained is the current data of all contacts and all pulses after zero point calibration, denoted as "calibrated current data of each contact". The "calibrated current data of each contact" for the first contact (T1) includes 10 calibrated current time series arrays obtained from, for example, 10 pulse excitation tests. These 10 time series are accurately aligned based on the pulse trigger time points. A new empty array is created, with the same length as the time series of a single pulse. For the first time point in the new array, the arithmetic mean of the current values of the 10 original arrays at this time point is calculated and stored in the first position of the new array. For the second time point in the new array, the arithmetic mean of the current values of the 10 original arrays at this time point is calculated and stored in the second position of the new array. Similarly, all time points are processed until all time points are processed. The average current time series obtained in this way is the "aggregated current data" of the T1 contact. In the same way, the 10 calibrated current time series of the T2 contact are aligned and averaged point by point to obtain the aggregated current data of the T2 contact; and the 10 calibrated current time series of the T3 contact are processed to obtain the aggregated current data of the T3 contact. The three aggregated current time series are collectively referred to as "contact shunt data" (here "shunt" is understood as distinguishing the data of different contacts), which reflects the average response characteristics of each contact under multiple excitations. Take the "aggregated current data" of the first contact (T1) (i.e. the average current time series obtained in the previous step). The sequence consists of current values at a series of discrete time points, with a time point interval of the sampling period of the data acquisition card (e.g. 1 microsecond). To calculate the current rate of change (dI / dt), a first-order backward difference method is used: for the i-th point in the sequence (i starts from 1 to N-1, N is the length of the sequence), the corresponding current rate of change is calculated as (current value[i]-current value[i-1]) / sampling period.For example, if the current value [i] = 105 A, the current value [i-1] = 100 A, and the sampling period is 1 microsecond, then the rate of change at this point is (105-100) / 0.000001 = 5,000,000 A / s or 5 A / µs. This calculation is performed for all applicable points in the aggregated current sequence of Tl (typically all points except the first one), resulting in a new time sequence, the "current rate of change curve" of Tl. Similarly, the backward difference method is applied to the aggregated current data of T2 and T3, generating the current rate of change curves of T2 and T3, respectively. These three curves constitute the "current rate of change curves" set. A threshold is determined for distinguishing significant changes from noise, for example, set to 10% of the maximum absolute value of the rate of change. The timestamp of the first point on the curve that exceeds the positive threshold is found and recorded as the rising edge start time. Next, the timestamp of the first point that falls below the positive threshold after the rate of change peak is found and recorded as the rising edge end time. Subsequently, the timestamp of the first point on the curve that falls below the negative threshold (i.e., less than -threshold) is found and recorded as the falling edge start time. Finally, the timestamp of the first point that rises above the negative threshold (i.e., greater than -threshold) after the rate of change valley is found and recorded as the falling edge end time. Then, the time interval [rising edge start time, rising edge end time] defines the rising edge interval of Tl. The time interval [falling edge start time, falling edge end time] defines the falling edge interval of Tl. The time interval [rising edge end time, falling edge start time] defines the steady state interval of Tl. These three intervals (each containing a start and end timestamp) are recorded. The exact same thresholding and interval finding logic is performed on the current rate of change curves of T2 and T3, resulting in the rising edge, steady state, and falling edge interval data of T2 and T3, respectively. Using the "jump edge interval data" of the first contact (Tl) obtained in the previous step, namely the rising edge interval [rising edge start time, rising edge end time] and the falling edge interval [falling edge start time, falling edge end time], we go back to the "current rate of change curve" of Tl. In this curve, the maximum value within the time period from the rising edge start time to the rising edge end time is found. This maximum value is the "maximum rising jump rate" of Tl. Similarly, the minimum value (typically a negative value) within the time period from the falling edge start time to the falling edge end time is found. This minimum value is the "maximum falling jump rate" of Tl (representing the fastest falling speed). These two rate values (in units of amperes per second) are recorded. For T2 and T3, the maximum and minimum values are also found from their respective current rate of change curves within their corresponding rising and falling edge intervals, resulting in the maximum rising and falling jump rates of T2 and T3, respectively. The set of all contact maximum rates is the sought-after result. The rise time is typically defined as the time interval required for the current to rise from 10% to 90% of its steady state low value. The fall time is defined as the time interval required for the current to fall from 90% to 10% of its steady state high value.The specific calculation method is that, in the rising edge interval, two time points are found at which the current value is close to 10% and 90% of the steady-state low value respectively, and the time difference between the two time points is calculated, that is, the rising time. Similarly, in the falling edge interval, two time points are found at which the current value is close to 90% and 10% of the steady-state high value respectively, and the time difference between the two time points is calculated, that is, the falling time. The rising time and the falling time of each contact point are recorded. The calibrated current data and its corresponding rate curve are obtained for each pulse excitation. For the first contact point (T1), for example, 10 pulse excitations, the logic of step S24 is independently performed for each excitation, and 10 groups of independent transition edge interval data are obtained, that is, 10 rising edge start time values, 10 rising edge end time values, 10 falling edge start time values and 10 falling edge end time values. Collect the 10 rising edge start time values, calculate the standard deviation, and the standard deviation is defined as the "rising edge start jitter value" of T1. Similarly, the standard deviation of the 10 rising edge end time values is calculated to obtain the "rising edge end jitter value"; the standard deviation of the 10 falling edge start time values is calculated to obtain the "falling edge start jitter value"; and the standard deviation of the 10 falling edge end time values is calculated to obtain the "falling edge end jitter value". The four jitter values (usually in nanoseconds or microseconds) are recorded as the transition edge jitter characteristics of T1. For T2 and T3, repeat the complete process: calculate the rate of change, identify the interval, collect the four types of time points, and calculate the standard deviation respectively to obtain the four transition edge jitter values of T2 and T3 respectively. After completing the calculation of the maximum transition rate (rising edge and falling edge), the transition time (rising time and falling time), and the transition edge jitter value (rising edge and falling edge) of each contact point, these independent characteristic parameters are combined to form contact transition characteristic data that can comprehensively describe the dynamic characteristics of the contact point. For each contact point, its contact transition characteristic data can include a feature vector containing its maximum rising transition rate, maximum falling transition rate, rising time, falling time, rising edge jitter value and falling edge jitter value, and the like.

[0123] Preferably, step S3 comprises the following steps:

[0124] Step S31: determining whether each contact point has a transition too fast or too slow event according to the maximum transition rate of each contact point, to obtain a rate anomaly flag of each contact point; wherein when the maximum transition rate of the contact point exceeds 500 A / s or is lower than 50 A / s, it is determined that the contact point has a transition rate anomaly;

[0125] Step S32: determining whether each contact point has a transition timeout or too short event according to the transition time of each contact point, to obtain a time anomaly flag of each contact point; wherein when the transition duration of the contact point exceeds 5 ms or is lower than 0.5 ms, it is determined that the contact point has a transition time anomaly;

[0126] Step S33: Determine whether each contact exists a jump jitter abnormal event by presetting a jitter threshold to each contact jump edge jitter value, and obtain a contact jitter abnormal flag; wherein, when the jump time deviation between adjacent two pulses of the contact jump edge exceeds 15%, it is determined that the contact exists a jump jitter abnormal event;

[0127] Step S34: Perform a comprehensive evaluation of the contact abnormal jump event based on the contact rate abnormal flag, the contact time abnormal flag and the contact jitter abnormal flag, and generate contact jump abnormal event evaluation data; wherein, when a certain contact simultaneously satisfies more than two abnormal flag conditions, or the same type of abnormal flag appears at least 5 times in 10 consecutive tests of the contact, it is determined that the contact has a serious jump abnormal event.

[0128] In the embodiments of the present application, the "maximum rising rate" and "maximum falling rate" of the first contact (e.g., T1) are extracted. The "maximum rising rate" is compared with the preset upper threshold of 500 A / s and lower threshold of 50 A / s. If the "maximum rising rate" is greater than 500 A / s or less than 50 A / s, it is determined that T1 has an abnormal rising rate. Similarly, the absolute value of the "maximum falling rate" is compared with 500 A / s and 50 A / s. If the absolute value of the "maximum falling rate" is greater than 500 A / s or less than 50 A / s, it is determined that T1 has an abnormal falling rate. A Boolean variable "T1 rate abnormality flag" is set to TRUE if the rising rate or falling rate (or both) is determined to be abnormal, and FALSE otherwise. For example, if the maximum rising rate of T1 is 620 A / s and the absolute value of the maximum falling rate is 100 A / s, the T1 rate abnormality flag is set to TRUE due to the abnormal rising rate. The comparison process is repeated for the second contact (T2) and the third contact (T3) to determine and record their respective "rate abnormality flags" (T2 rate abnormality flag, T3 rate abnormality flag). The "rising time" and "falling time" values in the record of the first contact (T1) are extracted. The "rising time" is compared with the preset upper threshold of 5 ms and lower threshold of 0.5 ms. If the "rising time" is greater than 5 ms or less than 0.5 ms, it is determined that T1 has an abnormal rising time. Similarly, the "falling time" is compared with 5 ms and 0.5 ms. If the "falling time" is greater than 5 ms or less than 0.5 ms, it is determined that T1 has an abnormal falling time. A Boolean variable "T1 time abnormality flag" is set to TRUE if the rising time or falling time (or both) is determined to be abnormal, and FALSE otherwise. For example, if the rising time of T1 is 0.3 ms and the falling time is 2 ms, the T1 time abnormality flag is set to TRUE due to the short rising time. The comparison process is repeated for the second contact (T2) and the third contact (T3) to determine and record their respective "time abnormality flags" (T2 time abnormality flag, T3 time abnormality flag). For the same contact, the rising time or falling time is calculated in two consecutive current pulse excitation tests. If the deviation between the two measured rising times exceeds 15% of their average, or the deviation between the two measured falling times exceeds 15% of their average, it is determined that the contact has a jump jitter abnormality, and a jitter abnormality flag is assigned to the contact.For example, in the first test, the rise time of a certain contact is 1 ms, in the second test, it is 1.3 ms, the average value is 1.15 ms, the deviation is 0.3 ms, and the deviation rate is about 0.3 / 1.15x100%≈26%, which exceeds the threshold of 15%, so the contact will be marked as having a rising edge jitter abnormality. The evaluation rules are as follows: if a certain contact simultaneously meets any two or more abnormal flag conditions in one test (for example, both fast transition and transition timeout exist, or both slow transition and jitter abnormality exist), it is determined that the contact has a serious transition abnormal event. In addition, considering that occasional factors may cause an abnormality in a single test, a judgment condition based on the results of multiple tests is also set: if a certain contact has the same type of abnormal flag in at least 5 of the 10 consecutive current pulse excitation tests (for example, 5 or more of the 10 consecutive tests have the rate abnormal flag of fast transition), it is also determined that the contact has a serious transition abnormal event. For the contacts determined to have a serious transition abnormal event, corresponding evaluation data will be generated, such as recording the number of the contact, the type of abnormality (including single multiple abnormality and multiple repeated abnormality), and the number of tests in which the abnormality occurs, etc. For example, if T1 has "rate abnormal flag"=TRUE, "time abnormal flag"=TRUE, and "jitter abnormal flag"=FALSE, it is determined that T1 is "serious abnormal" because it meets condition one (two flags are TRUE). For another example, although the aggregate data of T2 appears to be normal, it is still determined that T2 is "serious abnormal" because it meets condition two, although all three aggregate flags of T2 are FALSE, but in 10 pulse tests, there are 6 times of "time abnormality" (such as too short pulse duration). The same comprehensive evaluation logic is performed on T3. The final generated data set containing the evaluation results of T1, T2, and T3 (for example: "T1: serious abnormal, T2: serious abnormal, T3: normal") is the "contact transition abnormal event evaluation data".

[0129] Preferably, step S4 comprises the following steps:

[0130] Step S41: Calculate the total switch current according to the contact shunt data;

[0131] Step S42: Calculate the equivalent total resistance data by performing equivalent total resistance calculation on the total switch current using the power supply voltage signal in the contact group pulse response data;

[0132] Step S43: Perform contact instantaneous contact resistance iterative distribution based on the equivalent total resistance data and the contact shunt data to obtain a contact instantaneous resistance sequence;

[0133] Step S44: Calculate the resistance average value of each contact according to the contact instantaneous resistance sequence;

[0134] Step S45: Calculate the standard deviation of each contact resistance according to the sequence of the instantaneous resistance of each contact and the average value of the resistance;

[0135] Step S46: Calculate the resistance fluctuation rate of each contact in the power switch to be measured based on the average value of the resistance and the standard deviation of the resistance of each contact, and generate the contact resistance fluctuation rate.

[0136] In the embodiment of the present application, the currents of the parallel contacts working at the same time are superimposed. Therefore, at each sampling time, the instantaneous current values in the shunt data of all the contacts in the closed state are added to obtain the total current value flowing through the power switch at that time. Arranging the total current values calculated at each sampling time in time sequence, the time sequence of the total current of the switch is obtained. For example, assuming that the two output contacts corresponding to the two blades of a double-pole double-throw switch are closed at the same time to conduct current in a certain test stage, if the current value of the first contact is 2.5 amperes and the current value of the second contact is 2.3 amperes at a certain sampling time, then the total current of the switch at that time is 2.5+2.3=4.8 amperes. Performing the addition operation for all the sampling times, the complete total current data of the switch is obtained. The time sequence of the total current of the switch obtained using step S41 is used. The steady-state interval of the current pulse is determined, and the interval information can be obtained from the "steady-state section interval" in the "contact jump edge interval data" obtained in step S24 (for example, the intersection of the steady-state intervals of all the contacts is selected). A new time sequence array is created for storing the equivalent total resistance. Only in the identified steady-state time interval, the following calculation is performed for each time point t: the power supply voltage value V(t) at that time (it is necessary to confirm that this voltage is the accurately measured voltage drop across the switch, if not, compensation or differential voltage measurement needs to be used) and the total current value I_total(t) of the switch are read. The Ohm's law is applied to calculate the instantaneous equivalent total resistance R_total(t)=V(t) / I_total(t). The calculation result R_total(t) is stored in the corresponding time point position of the equivalent total resistance array. The division operation is repeated for all the time points in the steady-state interval. If I_total(t) approaches zero at some points, anti-division zero processing needs to be added (for example, the calculation is only performed when the current is greater than a certain threshold). The final resistance time sequence array in the steady-state interval, that is, the "equivalent total resistance data". Assuming that in the initial state, the contact resistances of all the parallel contacts are equal. At each sampling time, according to the equivalent total resistance at that time and the shunt current values of the contacts, the instantaneous resistance of each contact is preliminarily estimated by using the calculation formula of parallel resistance. Then, based on the preliminarily estimated contact resistance values, the shunt current of each contact is recalculated and compared with the actually measured shunt current. If there is a difference, the resistance estimation value of each contact is adjusted according to the size of the difference, the shunt current calculation and comparison are performed again, and the iteration process is repeated until the error between the calculated shunt current and the actually measured shunt current is less than a certain preset threshold or the maximum number of iterations is reached. The final resistance estimation value sequence of each contact at each sampling time is the instantaneous resistance sequence of each contact. For the instantaneous resistance sequence R_T1(t) of the first contact T1, the arithmetic mean of all the resistance values in the sequence is calculated.The specific operation is: sum up all the resistance values ​​in the sequence and then divide it by the total number of data points in the sequence (that is, the number of sampling points in the steady-state interval). The formula is: Average resistance_T1=(. ) / N, where Σ represents the sum of all time points t within the steady-state interval, and N is the number of points in the steady-state interval. This single value is the "average resistance" of contact T1. In exactly the same way, the arithmetic mean of the instantaneous resistance series R_T2(t) for T2 is calculated to obtain the "average resistance" of T2. The arithmetic mean of the instantaneous resistance series R_T3(t) for T3 is then calculated to obtain the "average resistance" of T3. Finally, the average resistance of the three contacts is obtained. For each instantaneous resistance value in the series, the square of the difference from the average is calculated. All squared differences are summed, then divided by the total number of sampling points minus one (as an unbiased estimate), and the square root of the result is taken to obtain the standard deviation of the resistance of the contact. A larger standard deviation indicates greater fluctuation in the instantaneous resistance of the contact around its average value, indicating a more unstable contact. For example, if the instantaneous resistance of a contact fluctuates significantly from its average value, the standard deviation of the resistance of that contact will be relatively large. Resistance standard deviation is an important indicator for determining whether a contact has transient faults such as poor contact or chatter. For the first contact, T1, calculate its resistance fluctuation using the formula: Fluctuation_T1 = (Standard Deviation_T1 / Average Resistance_T1) × 100%. The result is expressed as a percentage. For example, if Average Resistance_T1 = 0.5 milliohms and Standard Deviation_T1 = 0.05 milliohms, then Fluctuation_T1 = (0.05 / 0.5) × 100% = 10%. This 10% is the "Resistance Fluctuation" of contact T1. For the second contact, T2, use its Average Resistance_T2 and Standard Deviation_T2 and apply the same formula to calculate T2's "Resistance Fluctuation." For the third contact, T3, use its Average Resistance_T3 and Standard Deviation_T3 to calculate T3's "Resistance Fluctuation." The resulting set of three percentage values, {Fluctuation_T1, Fluctuation_T2, Fluctuation_T3}, constitutes the "Contact Resistance Fluctuation" data.

[0137] As an example of the present invention, refer to Figure 2 As shown, Figure 1 Detailed implementation steps of step S5 are shown in the flowchart. In this example, step S5 includes:

[0138] Step S51: grouping abnormal contacts of the power switch to be tested based on the evaluation data of abnormal contact transition events to obtain an abnormal switch contact group;

[0139] In the embodiment of the present application, each contact in the power switch is analyzed to identify the contact with abnormality. The evaluation data records the jump rate abnormality, jump time abnormality and jump jitter abnormality of each contact. All the contacts evaluated as having serious jump abnormality events are classified into a set to form a switch abnormal contact group. For example, if a four-contact power switch is evaluated by step S3, contact 1 and contact 3 are determined to have serious jump abnormality events (jump too slow and jitter too large), and the jump characteristics of contact 2 and contact 4 are normal, then the switch abnormal contact group contains contact 1 and contact 3.

[0140] Step S52: Perform abnormal contact magnetic field analysis on the switch abnormal contact group through the electromagnetic signals of each contact in the contact group pulse response data to obtain a contact magnetic field abnormality mode;

[0141] In the embodiment of the present application, the T1 and T3 corresponding magnetic field sensor time sequence data (including X, Y, Z three-axis components) after digital signal conversion are extracted from the original "contact group pulse response data". For the magnetic field signal of T1, the fast Fourier transform (FFT) is used to calculate its frequency spectrum in the jump edge interval (rising edge and falling edge, interval information from S24). The obtained frequency spectrum is compared with the frequency spectrum of the normal contact (for example, T2) in the same interval. If it is found that the energy of the frequency spectrum of T1 in a specific high frequency band (for example, above 10 kHz) is significantly higher than that of T2 (for example, more than 20 decibels), then the magnetic field abnormality mode of T1 is recorded as "switch transient high frequency magnetic field radiation enhancement". For the magnetic field signal of T3, the steady-state conduction interval (interval information from S24) is analyzed. The root mean square (RMS) value or peak-to-peak value of the magnetic field signal in the interval is calculated. If the RMS value of T3 is significantly higher than that of T2 (for example, more than a set threshold of 0.5 millitesla), or the signal waveform presents unexpected, amplitude exceeding noise level, continuous fluctuation or intermittent spikes, then the magnetic field abnormality mode of T3 is recorded as "magnetic field instability during steady-state conduction".

[0142] Step S53: Perform single contact fault type rule matching based on the contact magnetic field abnormality mode, contact resistance fluctuation rate and each contact jump abnormality event evaluation data to generate single contact fault type data;

[0143] In the embodiment of the present application, the abnormal contacts (e.g. T1, T3) determined in step S51, combined with the specific trigger conditions of the "severe jump abnormal event" (whether it is a rate abnormality, a time abnormality, or a combination of jitter abnormality) in S34, the "contact resistance fluctuation rate" value calculated in S46, and the "contact magnetic field abnormal pattern" determined in S52, are input into a pre-constructed fault diagnosis rule base (e.g. a set of expert rules stored in the form of if-else). For example, for contact T1: if the evaluation result of T1 is "severe jump abnormal event" (the trigger condition contains "jump time too short" and "jump rate too fast") and the resistance fluctuation rate of T1 is greater than 15% and the magnetic field abnormal pattern of T1 is "switch transient high-frequency magnetic field radiation enhancement", otherwise, the fault type of T1 is determined to be "contact ablation or severe wear". For contact T3: if the evaluation result of T3 is "severe jump abnormal event" (the trigger condition contains "jump jitter abnormality") and the resistance fluctuation rate of T3 is between 5% and 15% and the magnetic field abnormal pattern of T3 is "magnetic field instability during steady-state conduction", otherwise, the fault type of T3 is determined to be "insufficient contact pressure or spring mechanism aging". The fault type (such as "contact ablation or severe wear", "insufficient contact pressure") matched by each abnormal contact is recorded to form "single-contact fault type data".

[0144] Step S54: Perform health assessment on the power switch to be tested based on the single-contact fault type data, and then perform overall switch fault type processing and fault positioning to obtain power switch fault data.

[0145] In the embodiment of the present application, the evaluation rules are, for example: if all contacts are "normal", the health degree is "excellent"; if there is a "mild abnormality" but no "severe jump abnormal event" contact, the health degree is "fair"; if there is one "severe jump abnormal event" contact, the health degree is "attention needed"; if there are two or more "severe jump abnormal event" contacts, or there is a specific severe fault type (such as "contact soldering risk"), the health degree is "poor / needs immediate repair". Then, perform "overall switch fault type processing": summarize the fault types of all abnormal contacts to form a description of the overall fault condition of the switch. For example, if T1 is "contact ablation" and T3 is "insufficient contact pressure", the overall fault description is "the switch has multiple contact faults, including contact ablation (T1) and insufficient contact pressure (T3)". Finally, perform "fault positioning": clearly indicate the specific contact position where the fault occurs. For example, directly list the identifiers of the abnormal contacts ["T1", "T3"]. The health degree evaluation result, overall fault type description, and fault positioning information are integrated into a structured report object or file, which is the "power switch fault data".

[0146] Preferably, step S52 is specifically:

[0147] According to the electromagnetic signals of each contact in the contact group impulse response data, three-axis orthogonal direction magnetic field intensity processing is performed to obtain contact three-axis magnetic field intensity data;

[0148] The spatial position of the magnetic sensor is obtained; the spatial position of the magnetic sensor is spatially mapped with the contact three-axis magnetic field intensity data, and then magnetic field gradient calculation is performed to obtain magnetic field gradient distribution data;

[0149] According to the magnetic field gradient distribution data, gradient vector modulus value calculation is performed, and then the maximum vector modulus value position is extracted to obtain maximum magnetic field gradient data;

[0150] The magnetic field center offset of the abnormal contact group is analyzed through the magnetic field gradient distribution data to obtain the abnormal contact magnetic field offset;

[0151] According to the maximum magnetic field gradient data, the abnormal contact magnetic field offset, and the magnetic field gradient distribution data, contact magnetic field abnormal mode processing is performed to obtain the contact magnetic field abnormal mode.

[0152] In the embodiment of the application, if a three-axis magnetic field sensor is used, when collecting the electromagnetic signals of the contacts, the time series of the magnetic field intensity components in X, Y and Z three mutually orthogonal directions will be obtained synchronously. The data processing unit needs to record and organize the magnetic field signals in three directions collected by each contact to obtain the three-axis magnetic field intensity data corresponding to each sampling time of each contact in the entire test process. Precise measurement is performed when the fixture is designed, or a three-dimensional measuring device is used after deployment. After obtaining the three-dimensional coordinates (x, y, z) of each magnetic sensor, the spatial position information is associated with the three-axis magnetic field intensity data (Bx, By, Bz) of the corresponding contact at each sampling time to establish a spatial mapping relationship. Then, based on the change of the magnetic field intensity between adjacent sampling points and the relative position relationship between the magnetic sensor and the contact, the gradient of the magnetic field in space is calculated. The magnetic field gradient is a vector, which describes the rate and direction of the change of the magnetic field intensity in space. For a gradient vector (Gx, Gy, Gz), its modulus is The magnetic field gradient modulus distribution is obtained by calculating the modulus of all the calculated gradient vectors. Then, the maximum value of the modulus is found, as well as the spatial position corresponding to the maximum value. This maximum magnetic field gradient modulus reflects the region where the magnetic field strength changes most rapidly, which is usually related to the region of the maximum current density or the location of the arc discharge. The position of the maximum vector modulus indicates the spatial point where the change is most drastic. The magnetic field gradient distribution data is analyzed. Normally, the center of the magnetic field generated when the contacts are closed or opened should approximately coincide with the physical position of the contacts. When there is a fault in the contacts, such as poor contact or eccentric wear, the distribution of the current will change, causing the center of the magnetic field to deviate. By analyzing the magnetic field gradient distribution data, the center position of the magnetic field strength (which can be defined as the center of the region with the maximum modulus of the magnetic field gradient vector) is determined. Then, the distance and directional deviation between this magnetic field center and the physical center position of the contacts are calculated to obtain the abnormal contact magnetic field deviation. The "maximum magnetic field gradient data" (the maximum gradient value and its position), "abnormal contact magnetic field deviation" (the deviation vector of each abnormal contact), and the overall "magnetic field gradient distribution data" are integrated. A preset set of discrimination rules is applied: Rule one: if the "maximum magnetic field gradient value" is significantly higher than the baseline value (for example, more than 3 times the average gradient of the normal contacts) and its "position" is close to the physical edge or gap region of an abnormal contact, otherwise the magnetic field anomaly mode of the contact is marked as "local high current density or edge arc". Rule two: if the "magnetic field deviation" vector of an abnormal contact has a modulus greater than a threshold (for example, 2 mm) or its direction points to an unintended structural area, otherwise the magnetic field anomaly mode of the contact is marked as "main current path deviation or contact eccentricity". Rule three: if the "magnetic field gradient distribution data" shows that the gradient around an abnormal contact is generally lower than that of a normal contact, especially in the expected high gradient region, otherwise its mode is marked as "current distribution dispersion or poor contact". Rule four: if combined with time series analysis (back to step one data), the gradient shows abnormal high-frequency oscillation or long duration at the switching moment, otherwise it is marked as "abnormal switch arc behavior". According to these rules, each abnormal contact (such as T1, T3) is matched and judged, and finally each abnormal contact is given a descriptive label that best fits its magnetic field characteristics, such as "T1: edge arc" and "T3: main current path deviation". These label sets constitute the final "contact magnetic field anomaly mode" data.

[0153] Preferably, the present application also provides a power switch fault testing device, comprising a control system for executing the power switch fault testing method as described above, the control system comprising:

[0154] The switch pulse test module is used for deploying a switch multiplexing test fixture on the to-be-tested power switch, performing contact pulse signal processing on the to-be-tested power switch, generating an independent contact pulse excitation sequence, controlling the switch multiplexing test fixture to perform contact current pulse excitation test on the to-be-tested power switch through the independent contact pulse excitation sequence, and synchronously collecting contact group pulse response data;

[0155] The contact feature analysis module is used for performing contact excitation current aggregation according to the contact group pulse response data, obtaining each contact shunt data, performing contact jump feature analysis according to the contact shunt data, and obtaining contact jump feature data;

[0156] The contact abnormal jump evaluation module is used for performing contact abnormal jump event evaluation according to the contact jump feature data, and generating each contact jump abnormal event evaluation data.

[0157] The resistance fluctuation analysis module is used for performing contact resistance fluctuation rate analysis according to the contact group pulse response data, and generating contact resistance fluctuation rate.

[0158] The comprehensive fault diagnosis module is used for performing abnormal contact magnetic field analysis based on the contact group pulse response data, obtaining a contact magnetic field abnormal mode, performing single-contact fault type analysis according to the contact magnetic field abnormal mode, the contact resistance fluctuation rate and each contact jump abnormal event evaluation data, and obtaining power switch fault data.

[0159] The application can accurately quantify the state of a single contact and avoid the problem of signal aliasing of multiple contacts compared with the traditional overall test method. Through the aggregation analysis of the contact group pulse response data, not only the shunt condition of each contact can be quantified to evaluate the current sharing characteristics, but also the abnormal current distribution problems caused by potential contact poor contact, oxidation or mechanical wear can be detected. In addition, based on the evaluation of the contact jump feature, the abnormal jump event of a single contact at the opening and closing moment can be further identified, so that early faults affecting the reliability of the switch can be found in advance. Through the fine pulse excitation and response monitoring, dynamic current distribution analysis, microscopic jump feature evaluation, dynamic resistance stability consideration and multi-source information fusion diagnosis, the effective detection and accurate diagnosis of the single contact level of the multi-contact parallel power switch are realized, which greatly improves the comprehensiveness, sensitivity and accuracy of the test.

[0160] Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the application file are intended to be included in the application.

[0161] The foregoing is considered as illustrative only of the principles of the application. Numerous modifications and changes will readily occur to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the scope of the application is indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalents are intended to be embraced therein.

Claims

1. A power switch fault testing method, characterized in that: The following steps are involved: Step S1: deploying a switch multiplexing test fixture on the power switch to be tested; Process the contact pulse signal of the power switch to be tested and generate an independent contact pulse excitation sequence; Control the switch multiplexing test fixture through independent contact pulse excitation sequence, and perform contact current pulse excitation test on the power switch to be tested to synchronously collect contact group pulse response data; Step S2: performing contact excitation current aggregation based on the contact group pulse response data to obtain the shunt data of each contact; performing contact jump characteristic analysis based on the shunt data of each contact to obtain the contact jump characteristic data; Step S3: evaluating abnormal contact transition events based on the contact transition feature data to generate evaluation data for each abnormal contact transition event; Step S4: performing contact resistance fluctuation rate analysis based on the contact group pulse response data to generate a contact resistance fluctuation rate; Step S5: performing abnormal contact magnetic field analysis based on the contact group pulse response data to obtain a contact magnetic field abnormality pattern; Single contact fault type analysis is performed based on the contact magnetic field abnormality pattern, contact resistance fluctuation rate, and each contact jump abnormality event evaluation data to obtain power switch fault data.

2. The power switch fault testing method according to claim 1, characterized in that: Deploying a switch multiplexing test fixture for the power switch to be tested in step S1 includes: Constructing a switch multiplexing test fixture; wherein the switch multiplexing test fixture includes a programmable current source, a high-speed multiplexer, a data acquisition card, a current probe, and a magnetic field sensor; The output signal end of the current probe is electrically connected to a set of input channels of a high-speed multiplexer; the output signal of the magnetic field sensor is electrically connected to another set of input channels of the high-speed multiplexer; the output channel of the high-speed multiplexer is electrically connected to a data acquisition card; and the data acquisition card is connected to the terminal device via a wireless network; The input terminal of the power switch to be tested is electrically connected to a programmable current source. A current probe is clamped to the output terminal of each contact of the power switch to be tested, and a corresponding magnetic field sensor is placed near each current probe to deploy a switch multiplexing test fixture for the target power switch.

3. The power switch fault testing method according to claim 1, characterized in that: The contact pulse signal processing of the power switch to be tested in step S1 includes: Extract the switch rated current and number of contacts based on the power switch to be tested; Set the current pulse amplitude of each contact based on the switch rated current and the number of contacts; Processing the duration and interval of the safety test current pulse based on the current pulse amplitude by the contact current pulse amplitude to obtain the test pulse duration and interval; The current pulse subsequence is processed according to the contact current pulse amplitude, test pulse duration and interval time, and then the contact pulse signals are sorted to generate an independent contact pulse excitation sequence.

4. The power switch fault testing method according to claim 1, wherein: In step S1, controlling the switch multiplexing test fixture through an independent contact pulse excitation sequence and performing a contact current pulse excitation test on the power switch to be tested includes: The terminal device sends the independent contact pulse excitation sequence to the switch multiplexing test fixture for control signal encoding to obtain the pulse excitation control signal; Performing test status judgment on the switch multiplexing test fixture to obtain a test status flag; Based on the test status flag, the switch multiplexing test fixture is controlled by the pulse excitation control signal to perform contact current pulse excitation test, and the current probe, magnetic field sensor and switch power supply voltage of each contact are synchronously controlled to collect signals, and the excitation current signal of each contact, the electromagnetic signal of each contact and the power supply voltage signal are obtained respectively; The excitation current signal of each contact, the electromagnetic signal of each contact and the power supply voltage signal are transmitted to the terminal device, and then digital signal conversion is performed to obtain the contact group pulse response data.

5. The power switch fault testing method according to claim 1, wherein: Step S2 includes the following steps: Step S21: performing current calibration processing on each contact point according to the excitation current signal of each contact point in the contact group pulse response data to obtain calibrated current data of each contact point; Step S22: performing contact excitation current aggregation on the calibrated current data of each contact to obtain the shunt data of each contact; Step S23: Calculating the current change rate of each contact according to the current shunting data of each contact, and generating a current change rate curve of each contact; Step S24: identifying the transition edge interval according to the current change rate curve of each contact, and obtaining the transition edge interval data of each contact; wherein the transition edge interval identification includes rising edge, steady state segment and falling edge identification; Step S25: Calculating the maximum transition rate of each contact point based on the transition edge interval data of each contact point; Step S26: Calculating the transition time of each contact point based on the transition edge interval data of each contact point; Step S27: extracting the jitter value of each contact transition edge from each contact current change rate curve based on the transition edge interval data of each contact; Step S28: performing feature combination on the maximum transition rate of each contact point, the transition time of each contact point, and the transition edge jitter value of each contact point to obtain contact transition feature data.

6. The power switch fault testing method according to claim 1, wherein: Step S3 includes the following steps: Step S31: Determine whether each contact has an overly fast or overly slow transition event based on the maximum transition rate of each contact, and obtain an abnormality flag for each contact rate; wherein, when the maximum transition rate of a contact exceeds 500A / s or is less than 50A / s, it is determined that the contact has an abnormal transition rate; Step S32: Determine whether each contact has a transition timeout or too short event based on the transition time of each contact, and obtain a time abnormality flag for each contact; wherein, when the transition duration of a contact exceeds 5ms or is less than 0.5ms, it is determined that the contact has a transition time abnormality; Step S33: Determine whether each contact has a transition jitter abnormality event based on the jitter value of each contact's transition edge using a preset jitter threshold, and obtain a contact jitter abnormality flag. When the transition time deviation between two adjacent pulses of a contact's transition edge exceeds 15%, the contact is determined to have a transition jitter abnormality. Step S34: Perform a comprehensive assessment of contact abnormal jump events based on each contact rate abnormality flag, each contact time abnormality flag, and each contact jitter abnormality flag, and generate assessment data for each contact jump abnormality event; wherein, when a certain contact simultaneously meets any two or more abnormality flag conditions, or when the same type of abnormal flag appears at least 5 times in 10 consecutive tests of the contact, it is determined that a serious jump abnormality event has occurred at the contact.

7. The power switch fault testing method according to claim 1, characterized in that: Step S4 includes the following steps: Step S41: Calculating the total switch current based on the shunt data of each contact; Step S42: Calculating the equivalent total resistance of the total switch current using the power supply voltage signal in the contact group pulse response data to generate equivalent total resistance data; Step S43: performing iterative distribution of the instantaneous contact resistance of the contacts based on the equivalent total resistance data and the shunt data of each contact point to obtain an instantaneous resistance sequence of each contact point; Step S44: calculating the average resistance of each contact point based on the instantaneous resistance sequence of each contact point; Step S45: Calculating the standard deviation of each contact resistance based on the instantaneous resistance sequence of each contact and the average resistance value; Step S46: Calculate the resistance fluctuation rate of each contact in the power switch to be tested based on the average resistance value and the standard deviation of the resistance of each contact, and generate the contact resistance fluctuation rate.

8. The power switch fault testing method according to claim 1, wherein: Step S5 includes the following steps: Step S51: grouping abnormal contacts of the power switch to be tested based on the evaluation data of abnormal contact transition events to obtain an abnormal switch contact group; Step S52: performing abnormal contact magnetic field analysis on the abnormal contact group of the switch based on the electromagnetic signal of each contact in the contact group pulse response data to obtain an abnormal contact magnetic field pattern; Step S53: performing single contact fault type rule matching based on the contact magnetic field abnormality pattern, the contact resistance fluctuation rate, and the evaluation data of each contact jump abnormality event to generate single contact fault type data; Step S54: performing a health assessment on the power switch to be tested based on the single contact fault type data, and then performing overall switch fault type processing and fault location to obtain power switch fault data.

9. The power switch fault testing method according to claim 8, characterized in that: Step S52 is specifically as follows: Performing three-axis orthogonal magnetic field intensity processing on the electromagnetic signal of each contact in the contact group pulse response data to obtain the three-axis magnetic field intensity data of the contact; Obtaining the spatial position of the magnetic sensor; spatially mapping the spatial position of the magnetic sensor with the three-axis magnetic field strength data of the contact, and then calculating the magnetic field gradient to obtain the magnetic field gradient distribution data; Calculate the gradient vector modulus according to the magnetic field gradient distribution data, and then extract the maximum vector modulus position to obtain the maximum magnetic field gradient data; The magnetic field center offset of the abnormal contact group of the switch is analyzed by magnetic field gradient distribution data to obtain the magnetic field offset of the abnormal contact; The contact magnetic field abnormality pattern is processed according to the maximum magnetic field gradient data, the abnormal contact magnetic field offset and the magnetic field gradient distribution data to obtain the contact magnetic field abnormality pattern.

10. A power switch fault testing device, characterized in that: A control system is provided for executing the power switch fault testing method according to claim 1, the control system comprising: A switch pulse test module is used to deploy a switch multiplexing test fixture for the power switch under test; process contact pulse signals of the power switch under test to generate independent contact pulse excitation sequences; control the switch multiplexing test fixture using the independent contact pulse excitation sequences, and perform contact current pulse excitation tests on the power switch under test to synchronously collect contact group pulse response data; The contact feature analysis module is used to aggregate the contact excitation current according to the contact group pulse response data to obtain the shunt data of each contact; and to perform contact jump feature analysis according to the shunt data of each contact to obtain the contact jump feature data; The contact abnormal jump evaluation module is used to evaluate the contact abnormal jump event based on the contact jump characteristic data and generate evaluation data of each contact abnormal jump event; Resistance fluctuation analysis module, used to analyze contact resistance fluctuation rate based on contact group pulse response data and generate contact resistance fluctuation rate; The comprehensive fault diagnosis module is used to analyze abnormal contact magnetic fields based on the contact group pulse response data to obtain the contact magnetic field abnormality pattern; and to analyze the single contact fault type based on the contact magnetic field abnormality pattern, contact resistance fluctuation rate, and each contact jump abnormal event evaluation data to obtain the power switch fault data.

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