Power switch fault test device and test method

Abstract

The invention relates to the technical field of switch fault testing, in particular to a power switch fault testing device and 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 the power switch to be tested, and synchronously acquiring contact group pulse response data; according to the contact group pulse response data, contact abnormal jump event evaluation, contact resistance fluctuation rate analysis and contact magnetic field abnormal mode analysis are carried out, and then single-contact fault type analysis is carried out according to the contact magnetic field abnormal mode, the contact resistance fluctuation rate and the jump abnormal event evaluation data of each contact. And obtaining power switch fault data. According to the invention, independent current pulse excitation testing is carried out on each contact of the power switch, so that single-contact-level fault detection is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of switch fault testing, and particularly to a power switch fault testing device and a testing method. Background Art

[0002] Power switches, as core basic components in power electronic systems, power transmission and distribution networks, industrial automation control, and various electronic devices, undertake the key tasks of connecting, carrying, and breaking circuit currents. In high-voltage and high-current application scenarios, such as power circuit breakers, high-power contactors, and heavy-duty relays, in order to improve the current-carrying capacity, reduce the temperature rise and electrical wear of single contacts, enhance the breaking performance, and improve the overall reliability, a design structure with multiple contacts in parallel is often adopted. In this structure, multiple independent moving and static contact pairs are connected in parallel to jointly undertake the on-off task of the load current. Ideally, each parallel contact should act synchronously, evenly share the current, and maintain a low and consistent contact resistance. However, traditional power switch testing methods, such as simple on-off testing, static contact resistance measurement (such as using a micro-ohmmeter), insulation resistance testing, withstand voltage testing, action time measurement (closing time, opening time, closing-opening non-synchronism, etc.), and temperature rise testing under rated load, although they can reflect the basic performance and some fault modes of the switch to a certain extent, cannot achieve fine-grained fault testing of each independent contact, and it is difficult to distinguish normal current fluctuations and abnormal contact jump phenomena. Summary of the Invention

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

[0004] To achieve the above object, a power switch fault testing method includes the following steps: Step S1: Deploy a switch multiplexing test fixture for the power switch to be tested; perform contact pulse signal processing on the power switch to be tested to generate an independent contact pulse excitation sequence; control the switch multiplexing test fixture through the independent contact pulse excitation sequence, and perform contact current pulse excitation testing on the power switch to be tested to synchronously collect contact group pulse response data; Step S2: Aggregate the contact excitation currents according to the contact group pulse response data to obtain the shunt data of each contact; analyze the contact jump characteristics according to the shunt data of each contact to obtain the contact jump characteristic data; Step S3: Evaluate the contact abnormal jump events according to the contact jump characteristic data to generate the evaluation data of each contact jump abnormal event; Step S4: Analyze the contact resistance volatility according to the contact group pulse response data to generate the contact resistance volatility; Step S5: Perform abnormal contact magnetic field analysis based on the contact group pulse response data to obtain the contact magnetic field abnormal pattern; perform single-contact fault type analysis based on the contact magnetic field abnormal pattern, the contact resistance volatility, and the evaluation data of each contact jump abnormal event to obtain the power switch fault data.

[0005] Through the introduction of a multiplexing test fixture and contact pulse signal processing, the present invention realizes the independent excitation and response measurement of each parallel contact in the power switch, 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 tests, static contact resistance measurements, withstand voltage tests, etc., the present invention can dynamically test each contact in the form of pulse excitation during the contact operation process, so as to obtain its independent pulse response characteristics, further improving the detection ability of the current distribution between contacts, dynamic jump characteristics, and microscopic fault signs. Through the aggregation analysis of the pulse response data of the contact group, not only can the shunt situation of each contact be quantified and its current sharing characteristics be evaluated, but also abnormal current distribution problems caused by potential poor contact, oxidation, or mechanical wear of the contacts can be detected. Based on the evaluation of the contact jump characteristics, abnormal jump events of a single contact at the moment of opening and closing can be further identified, so as to detect early faults affecting the switch reliability in advance. At the same time, the volatility analysis of the contact resistance can effectively characterize the stability of the contact state, avoiding the problem that traditional static resistance measurements cannot reflect the dynamic contact quality of the contacts, and improving the recognition accuracy of faults such as contact aging and ablation. In addition, by combining abnormal contact magnetic field analysis, the present invention can identify phenomena such as unstable contact, welding, or local arc discharge existing through changes in electromagnetic characteristics, further expanding the detectable range of fault types. Finally, through the fusion of the contact magnetic field abnormal pattern, the contact resistance volatility, and the evaluation data of jump abnormal events, refined fault type analysis at the single-contact level is realized, breaking through the limitation that traditional methods can only perform overall discrimination, and improving the fault detection accuracy and diagnostic ability of the multi-contact parallel power switch. Therefore, a power switch fault test method of the present invention realizes the effective detection and accurate diagnosis of deep, dynamic, early, and hidden faults at the single-contact level of the multi-contact parallel power switch through refined pulse excitation and response monitoring, dynamic current distribution analysis, microscopic jump characteristic evaluation, dynamic resistance stability consideration, and multi-source information fusion diagnosis, greatly improving the comprehensiveness, sensitivity, and accuracy of the test.

[0006] Preferably, the deployment of the switch multiplexing test fixture for the power switch to be tested in step S1 includes: Construct 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 terminal of the current probe is electrically connected to a set of input channels of the 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 the data acquisition card; the data acquisition card is connected to the terminal device through a wireless network; Electrically connect the input terminal of the power switch to be tested to the programmable current source, Clamp the output terminal of each contact of the power switch to be tested with the current probe in a contact manner, and place a corresponding magnetic field sensor near each current probe, so as to deploy a switch multiplexing test fixture for the target power switch.

[0007] The switch multiplexing test fixture constructed by the present invention 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 precise contact pulse excitation, ensuring the quality and repeatability of the test signal. By clamping the output terminal of each contact of the power switch to be tested with the current probe and configuring a corresponding magnetic field sensor for each contact, the current pulse response of each contact and the surrounding magnetic field information 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.

[0008] Preferably, the processing of the contact pulse signal for the power switch to be tested in step S1 includes: Extract the switch rated current and the number of contacts according to 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; Based on the current pulse amplitude, process the duration and interval of the safety test current pulse through the contact current pulse amplitude to obtain the test pulse duration and interval; Perform current pulse subsequence processing according to the contact current pulse amplitude, test pulse duration and interval, and then sort the contact pulse signals to generate an independent contact pulse excitation sequence.

[0009] According to the rated current and the number of contacts of the switch, the present invention reasonably sets the current pulse amplitude of each contact. This parameterized setting method can ensure that the applied excitation signal can effectively stimulate the electrical characteristics of the contacts without causing potential damage to the switch due to excessive current impact, reflecting the unity of the safety and effectiveness of the test. By considering the requirements of the safety test current pulse and reasonably setting the duty cycle and repetition frequency of the pulse, it is possible to avoid overheating of the contacts or other unexpected effects caused by long-term or high-frequency excitation, ensuring the stability of the test process and the reliability of the data. By performing current pulse subsequence processing on the current pulse amplitude, test pulse duration, and interval time, and sorting the contact pulse signals, an independent contact pulse excitation sequence is finally generated, realizing precise and controllable excitation of each contact. This method of customizing an independent excitation sequence for each contact enables avoiding the mutual interference caused by the simultaneous operation of all contacts during the multi-contact parallel switch test, thereby more clearly obtaining the response characteristics of a single contact. The ordered pulse excitation sequence also provides a time reference for subsequent data analysis, facilitating the differentiation and correlation of the response signals of different contacts.

[0010] Preferably, in step S1, controlling the switch multiplexing test fixture through the independent contact pulse excitation sequence and performing the 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 a pulse excitation control signal; Judging the test state of the switch multiplexing test fixture to obtain a test state flag; Based on the test state flag, controlling the switch multiplexing test fixture to perform the contact current pulse excitation test through the pulse excitation control signal, synchronously controlling the current probe, magnetic field sensor, and switch power supply voltage of each contact for signal acquisition, and respectively obtaining the excitation current signal of each contact, the electromagnetic signal of each contact, and the power supply voltage signal; Transmitting the excitation current signal of each contact, the electromagnetic signal of each contact, and the power supply voltage signal to the terminal device, and then performing digital signal conversion to obtain the contact group pulse response data.

[0011] The present invention transmits the generated independent contact pulse excitation sequence to the switch multiplexing test fixture through the terminal device and performs control signal encoding, ensuring that the excitation signal can be accurately recognized and executed by the test fixture, and realizing the reliable transmission of test instructions. Before performing the excitation test, the test state of the switch multiplexing test fixture is judged, which can effectively avoid test errors or damages caused by abnormal device states, and ensure the safety and reliability of the test process. 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, realizing independent and orderly excitation of each contact. While performing the contact current pulse excitation, 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, electromagnetic signal, and power supply voltage signal of each contact are respectively obtained.

[0012] Preferably, step S2 includes the following steps: Step S21: Perform current calibration processing on each contact according to the excitation current signals of each contact in the contact group pulse response data to obtain the calibrated current data of each contact; Step S22: Aggregate the excitation currents of each contact for the calibrated current data of each contact to obtain the shunt data of each contact; Step S23: Calculate the current change rate of each contact according to the shunt data of each contact, and generate the current change rate curve of each contact; Step S24: Identify the jump edge interval according to the current change rate curve of each contact to obtain the jump edge interval data of each contact; among them, the jump edge interval identification includes rising edge, steady state section, and falling edge identification; Step S25: Calculate the maximum jump rate of each contact for the jump edge interval data of each contact; Step S26: Calculate the jump time of each contact according to the jump edge interval data of each contact; Step S27: Extract 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; Step S28: Combine the maximum jump rate of each contact, the jump time of each contact, and the jump edge jitter value of each contact to obtain the jump feature data of the contact.

[0013] The present invention calibrates the excitation current signals of each contact, effectively eliminating sensor errors and system biases. Through the aggregation of contact excitation currents, the instantaneous shunt data of each contact are directly obtained, clearly revealing the specific current distribution among parallel contacts and quantifying the degree of current imbalance. By calculating the current change rate of each contact and generating corresponding curves, the solution can more carefully observe the dynamic response of the contact during the on-off process. Based on these current change rate curves, the solution can accurately identify the jump edge intervals, including the rising edge, steady state segment, and falling edge, thereby decomposing the action process of the contact into finer stages for analysis. This refined interval division provides an accurate time reference for calculating the maximum jump rate and jump time in the subsequent stage. The calculation of the maximum jump rate and jump time of each contact directly reflects the rapidity and synchronization of the contact action, which are key indicators 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 during the contact process of the contact, such as minute vibrations on the contact surface and foreign object intrusion, which are potential manifestations of early poor contact and mechanism looseness. Quantifying the jump edge jitter can more sensitively capture these subtle abnormal phenomena.

[0014] Preferably, step S3 includes the following steps: Step S31: Determine whether there is an event of too fast or too slow jump for each contact according to the maximum jump rate of each contact, and obtain the rate anomaly flag for each contact; wherein, when the maximum jump rate of the contact exceeds 500 A / s or is lower than 50 A / s, it is determined that the contact has a jump rate anomaly; Step S32: Determine whether there is an event of too long or too short jump for each contact according to the maximum jump rate of each contact, and obtain the time anomaly flag for each contact; wherein, when the jump duration of the contact exceeds 5 ms or is lower than 0.5 ms, it is determined that the contact has a jump time anomaly; Step S33: Determine whether there is an event of abnormal jump edge jitter for each contact by judging the jump edge jitter value of each contact through a preset jitter threshold, and obtain the jitter anomaly flag for each contact; wherein, when the jump time deviation between two adjacent pulses of the contact jump edge exceeds 15%, it is determined that the contact has an abnormal jump edge jitter; Step S34: Based on the rate anomaly flag for each contact, the time anomaly flag for each contact, and the jitter anomaly flag for each contact, conduct a comprehensive evaluation of the abnormal jump events of the contacts, and generate the evaluation data of the abnormal jump events of each contact; wherein, when a certain contact simultaneously meets more than two abnormal flag conditions, or at least 5 times of the same type of abnormal flag appear in 10 consecutive tests of the contact, it is determined that the contact has a serious abnormal jump event.

[0015] The present invention judges the maximum jump rate of each contact through a preset rate threshold (too fast or too slow), and can quickly identify events with abnormal contact action speed, which are often related to problems such as blockage of the contact mechanism, poor lubrication, or insufficient driving force. By evaluating the jump time of each contact through a preset time threshold (timeout or too short), events with abnormal contact action time can be effectively detected, such as contact opening and closing delay, rapid disconnection caused by poor contact, etc. These time anomalies directly reflect potential problems in the contact mechanism or electrical circuit. The analysis of the jump edge jitter value based on a preset jitter threshold is introduced to judge whether there is an abnormal event of jump jitter. 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 minute separation and coincidence of the contact surface, looseness of the mechanical components, etc. Based on the rate anomaly flag, time anomaly flag, and jitter anomaly flag for comprehensive evaluation, more stringent determination conditions for severe jump anomaly events are set, such as simultaneously satisfying multiple anomaly flags or frequently occurring the same type of anomaly in multiple tests, which can effectively exclude the interference of accidental factors, improve the reliability of fault determination, and distinguish abnormal events of different severity levels.

[0016] Preferably, step S4 includes the following steps: Step S41: Calculate the total switch current according to the shunt data of each contact; Step S42: Calculate the equivalent total resistance of the total switch current through the power supply voltage signal in the contact group pulse response data to generate equivalent total resistance data; Step S43: Based on the equivalent total resistance data and the shunt data of each contact, perform iterative distribution of the instantaneous contact resistance of the contacts to obtain the instantaneous resistance sequence of each contact; Step S44: Calculate the average resistance of each contact according to the instantaneous resistance sequence of each contact; 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; Step S46: Calculate the resistance volatility of each contact in the power supply switch to be measured based on the average resistance and the standard deviation of the resistance of each contact to generate the contact resistance volatility.

[0017] The present invention obtains the total switch current by aggregating the shunt data of each contact, combines the synchronously collected power supply voltage signal, and adopts the iterative distribution method of the instantaneous contact resistance of the contacts. Based on the equivalent total resistance and the shunt data of each contact, the instantaneous resistance sequence of each contact is deduced, which can reflect the resistance change of the contact under the current pulse excitation, and quantifies the average contact resistance level and its fluctuation degree of each contact. The average value reflects the overall conductivity of the contact, while the standard deviation characterizes the stability of the contact resistance. Based on the calculated average resistance and standard deviation, the resistance volatility is a comprehensive index, which reflects the change degree of the contact resistance relative to its average value, and can effectively evaluate the stability and reliability of the contact. A higher resistance volatility 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.

[0018] Preferably, step S5 includes the following steps: Step S51: Group the abnormal contacts of the power switch to be tested through the evaluation data of each contact jump abnormal event to obtain the switch abnormal contact group; Step S52: Analyze the abnormal contact magnetic field of the switch abnormal contact group through the electromagnetic signals of each contact in the contact group pulse response data to obtain the contact magnetic field abnormal mode; Step S53: Based on the contact magnetic field abnormal mode, the contact resistance volatility, and the evaluation data of each contact jump abnormal event, perform single-contact fault type rule matching to generate single-contact fault type data; Step S54: Evaluate the health of the power switch to be tested through the single-contact fault type data, and then perform overall fault type processing and fault location of the switch to obtain the power switch fault data.

[0019] The present invention uses the evaluation data of each contact jump abnormal event generated previously to group the contacts of the power switch to be tested, identifies the contacts with abnormalities, effectively focuses the target of fault analysis, and improves the efficiency. For the identified abnormal contact group, use the electromagnetic signals of each contact in the contact group pulse response data to conduct in-depth abnormal contact magnetic field analysis. The magnetic field information can reflect the local characteristics of the contact current distribution and potential physical structure abnormalities. By comprehensively analyzing the contact magnetic field abnormal mode, the contact resistance volatility, and the evaluation data of each contact jump abnormal event, it is possible to more comprehensively and accurately judge the specific fault type of each abnormal contact, such as mechanical faults (such as slow action, jitter), contact faults (such as excessive or unstable contact resistance), or electromagnetic abnormalities, etc., and evaluate the overall health of the power switch to be tested, realizing the automation and intelligence of fault diagnosis.

[0020] Preferably, step S52 is specifically: Process the magnetic field intensity in the three-axis orthogonal directions based on the electromagnetic signals of each contact in the contact group pulse response data to obtain the three-axis magnetic field intensity data of the contacts; Obtain the spatial position of the magnetic sensor; perform spatial mapping on the spatial position of the magnetic sensor and the three-axis magnetic field intensity data of the contacts, and then calculate the magnetic field gradient to obtain the magnetic field gradient distribution data; Calculate the magnitude of the gradient vector based on the magnetic field gradient distribution data, and then extract the position of the maximum vector magnitude to obtain the maximum magnetic field gradient data; Analyze the magnetic field center offset of the abnormal contact group of the switch through the magnetic field gradient distribution data to obtain the magnetic field offset of the abnormal contact; Perform processing on the magnetic field anomaly mode of the contacts based on the maximum magnetic field gradient data, the magnetic field offset of the abnormal contacts, and the magnetic field gradient distribution data to obtain the magnetic field anomaly mode of the contacts.

[0021] The present invention processes the electromagnetic signals of each contact for the magnetic field intensity in the three-axis orthogonal directions. By capturing the magnetic field intensities in three orthogonal directions, it can more comprehensively reflect the magnetic field distribution around the contacts. Combining with the spatial position information of the magnetic sensor, performing spatial mapping on the magnetic field intensity data, and calculating the magnetic field gradient distribution data can more sensitively reveal local anomalies in the current path, such as current contraction or diffusion caused by poor contact of the contacts. Calculate the magnetic field gradient distribution. Calculate the magnitude of the gradient vector 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 violently, which is the key part where faults occur. Ideally, the magnetic field center around the contact should be aligned with the physical center of the contact; when there is poor contact or uneven current distribution at the contact, the magnetic field center will shift. The magnitude and direction of the magnetic field offset can reflect the nature and degree of the fault. Considering the maximum magnetic field gradient data, the magnetic field offset of the abnormal contacts, and the overall magnetic field gradient distribution data comprehensively, and performing processing on the magnetic field anomaly mode of the contacts can identify various magnetic field anomaly modes, such as abnormal increase or decrease in 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.).

[0022] Preferably, the present invention also provides a power switch fault test device, including a control system for executing the power switch fault test method as described above. The control system includes: A switch pulse test module for 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 to perform contact current pulse excitation testing on the power switch to be tested through the independent contact pulse excitation sequence, and synchronously collecting the 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 analyze the contact jump characteristics according to the shunt data of each contact to obtain the contact jump characteristic data. The contact abnormal jump evaluation module is used to evaluate the contact abnormal jump event according to the contact jump characteristic data and generate the evaluation data of each contact jump abnormal event. The resistance fluctuation analysis module is used to analyze the contact resistance volatility according to the contact group pulse response data and generate the contact resistance volatility. The comprehensive fault diagnosis module is used to analyze the abnormal contact magnetic field based on the contact group pulse response data to obtain the abnormal contact magnetic field mode; and analyze the single contact fault type according to the abnormal contact magnetic field mode, the contact resistance volatility, and the evaluation data of each contact jump abnormal event to obtain the power switch fault data. Description of the Drawings

[0023] Figure 1 It is a schematic flow chart of the steps of the power switch fault test method of the present invention; Figure 2 is Figure 1 a detailed implementation step flow chart of step S5 in The realization, functional characteristics and advantages of the object of the present invention will be further described in conjunction with the embodiments with reference to the drawings. Specific Embodiments

[0024] The technical method of the present invention will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work fall within the protection scope of the present invention.

[0025] In addition, the drawings are only schematic diagrams of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings represent the same or similar parts, and thus their repeated description will be omitted. Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. The functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor methods and / or microcontroller methods.

[0026] It should be understood that although terms such as "first", "second", etc. may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another. For example, without departing from the scope of the exemplary embodiments, the first unit may be referred to as the second unit, and similarly, the second unit may be referred to as the first unit. The term "and / or" used herein includes any and all combinations of one or more of the listed associated items.

[0027] To achieve the above object, please refer to Figures 1 to 2 , the present invention provides a method for testing power switch failures, including the following steps: Step S1: Deploy a switch multiplexing test fixture for the power switch to be tested; perform contact pulse signal processing on the power switch to be tested to generate an independent contact pulse excitation sequence; control the switch multiplexing test fixture through the independent contact pulse excitation sequence, and perform a contact current pulse excitation test on the power switch to be tested to synchronously collect contact group pulse response data; Step S2: Aggregate the contact excitation currents according to the contact group pulse response data to obtain the shunt data of each contact; analyze the contact jump characteristics according to the shunt data of each contact to obtain the contact jump characteristic data; Step S3: Evaluate the contact abnormal jump events according to the contact jump characteristic data to generate the evaluation data of each contact jump abnormal event; Step S4: Analyze the contact resistance volatility according to the contact group pulse response data to generate the contact resistance volatility; Step S5: Analyze the abnormal contact magnetic field based on the contact group pulse response data to obtain the abnormal contact magnetic field pattern; perform single-contact fault type analysis according to the abnormal contact magnetic field pattern, the contact resistance volatility, and the evaluation data of each contact jump abnormal event to obtain the power switch fault data.

[0028] In the embodiment of the present invention, the method for testing power switch failures includes the following steps: Step S1: Deploy a switch multiplexing test fixture for the power switch to be tested; perform contact pulse signal processing on the power switch to be tested to generate an independent contact pulse excitation sequence; control the switch multiplexing test fixture through the independent contact pulse excitation sequence, and perform a contact current pulse excitation test on the power switch to be tested to synchronously collect contact group pulse response data; In an embodiment of the present invention, a switching 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 triaxial magnetic field sensors (range ±2mT, resolution 0.1mT). The output signals of current probe 1 and current probe 2 are respectively connected to channel 1 and channel 2 of the high-speed multiplexer; the X, Y, and Z axis output signals of magnetic field sensor 1 and magnetic field sensor 2 are respectively connected to channels 3 - 5 and channels 6 - 8 of the high-speed multiplexer; the output end of the high-speed multiplexer is connected to channel 1 of the data acquisition card; the data acquisition card is connected to a terminal device configured with test control and data analysis programs through W If I. Then, the common input terminal of the power switch to be tested is connected to the positive and negative poles of the programmable current source, and the current direction is set. Current probe 1 is used to clamp the output lead of contact A, and current probe 2 is used to clamp the output lead of contact B. Magnetic field sensor 1 is fixedly placed near current probe 1 so that its sensitive axis is roughly aligned with the current direction of contact A; similarly, magnetic field sensor 2 is fixedly placed near current probe 2 so that its sensitive axis is roughly aligned with the current direction of contact B. To process the contact pulse signal, the terminal device sets the current pulse amplitude of each contact to 80% of the rated current of the power switch, i.e., 4A, according to the rated current of 5A of the power switch and the number of two output contacts. Based on this amplitude and considering the heat dissipation characteristics of the power switch, the test pulse duration is set to 5ms, and the interval time is set to 50ms. Current pulse subsequences containing 10 identical pulse parameters are generated for contact A and contact B respectively. When sorting the contact pulse signals, an alternating excitation strategy is adopted. First, the path of contact A is excited 10 times, and then the path of contact B is excited 10 times to generate an independent contact pulse excitation sequence containing 20 pulses. The terminal device sends this excitation sequence to the test fixture through W If I, controls the programmable current source to output current pulses according to the set timing and parameters, and synchronously collects the excitation current signals (through the current probes), triaxial electromagnetic signals (through the magnetic field sensors), and voltage signals at the power input end of contact A and contact B through the high-speed multiplexer and the data acquisition card to obtain contact group pulse response data containing current, magnetic field, and voltage time series.

[0029] Step S2: Aggregate the contact excitation currents according to the contact group pulse response data to obtain the shunt data of each contact; analyze the contact jump characteristics according to the shunt data of each contact to obtain the contact jump characteristic data; In an embodiment of the present invention, 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 single-pole double-throw and only one contact conducts during each excitation test, the shunt data of each contact is its respective excitation current signal. For example, during 10 pulses of exciting contact A, the current waveform of contact A is recorded; during 10 pulses of exciting contact B, the current waveform of contact B is recorded. Then, calculate the current change rate of the current waveform data of each contact to obtain the current change rate curves of contact A and contact B. According to these curves, identify the rising edge, steady-state section, and falling edge intervals of each pulse. For each pulse of each contact, calculate the maximum jump rate, rise time, and fall time of its rising edge and falling edge. Further, for each contact, calculate the deviation of the jump time between consecutive pulses to obtain the jitter value of the jump edge of each contact. Finally, combine the maximum jump rate, jump time, and jump edge jitter value of each contact to form the contact jump characteristic data of contact A and contact B respectively.

[0030] Step S3: Evaluate the abnormal jump events of the contacts according to the contact jump characteristic data, and generate the evaluation data of the abnormal jump events of each contact; In an embodiment of the present invention, an abnormal jump event evaluation is performed on each contact. For each pulse of contact A, determine whether the maximum jump rate of its rising edge exceeds 500 A / s or is lower than 50 A / s. If it exceeds, mark it with a rate-too-fast / too-slow abnormal flag. Determine whether its rise time exceeds 5 ms or is lower than 0.5 ms. If it exceeds, mark it with a time-out / too-short abnormal flag. Compare whether the deviation of the rise time between two consecutive pulses of contact A exceeds 15%. If it exceeds, mark it with a jitter abnormal flag. The same judgment is made for contact B. For example, if the rise time of a certain pulse of contact A is 6 ms, mark it with a time-out abnormal flag. If contact B has a situation where the maximum jump rate of the rising edge is lower than 40 A / s in 6 out of 10 consecutive tests, mark that contact B has a rate abnormality of too-slow jump (meeting the condition of consecutive multiple abnormalities). Comprehensively analyze the abnormal flags of each contact. For example, if contact A simultaneously has two flags of too-slow jump and jitter abnormality in a certain test, determine that contact A has a serious jump abnormal event and record the event.

[0031] Step S4: Analyze the contact resistance volatility according to the contact group pulse response data, and generate the contact resistance volatility; In an embodiment of the present invention, the equivalent total resistance of the power switch during each excitation process is calculated using the power supply voltage and the total current. Since it is a single-pole double-throw switch and only one contact conducts each time, this equivalent total resistance is approximately equal to the resistance of the conducting contact. For each excitation of contact A, an instantaneous resistance sequence of contact A is obtained; for each excitation of contact B, an instantaneous resistance sequence of contact B is obtained. Then, the average resistance values of the instantaneous resistance sequences of contact A and contact B are calculated respectively. Further, the standard deviations of the resistance of the instantaneous resistance sequences of contact A and contact B are calculated. Finally, the standard deviations of the resistance of contact A and contact B are divided by their corresponding average resistance values respectively to obtain the contact resistance volatility of contact A and contact B.

[0032] Step S5: Based on the contact group pulse response data, perform abnormal contact magnetic field analysis to obtain the contact magnetic field abnormal pattern; according to the contact magnetic field abnormal pattern, the contact resistance volatility, and the evaluation data of each contact jump abnormal event, perform single-contact fault type analysis to obtain the power switch fault data.

[0033] In an embodiment of the present invention, assuming that contact B is identified as having a serious abnormal slow jump, the three-axis electromagnetic signals corresponding to contact B collected in step S1 are analyzed. Calculate the three-axis magnetic field intensity data of contact B during each excitation process, and perform magnetic field gradient calculation to obtain the magnetic field gradient distribution data. Calculate the gradient vector modulus value, extract the position of the maximum vector modulus value to obtain the maximum magnetic field gradient data. Analyze the offset of the magnetic field center of contact B relative to its physical position to obtain the magnetic field offset of the abnormal contact B. Combine the maximum magnetic field gradient data, the magnetic field offset, and the overall shape of the magnetic field gradient distribution of contact B to determine whether there is a specific magnetic field abnormal pattern, such as extremely weak magnetic field intensity, slow rise of magnetic field signal, etc. Then, match the magnetic field abnormal pattern of contact B, the contact resistance volatility of contact B obtained in step S4 (such as 0.6), and the abnormal evaluation data of slow jump obtained in step S3 with the preset fault rules. For example, if there is a rule in the rule library that "slow jump + weak magnetic field intensity + high resistance volatility -> poor contact (oxidation) of the contact", then it is determined that the fault type of contact B is poor contact (oxidation) of the contact. If contact A is evaluated as normal in step S3, its fault type is "no fault". Finally, summarize the fault types of contact A and contact B to form the fault data of the power switch, such as: "Contact A: no fault; Contact B: poor contact (oxidation) of the contact". And according to the number and type of faulty contacts, give a health assessment of the power switch, such as "minor fault, it is recommended to check contact B".

[0034] Preferably, the switch multiplexing test fixture deployed for the power switch to be tested in step S1 includes: Construct 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 terminal of the current probe is electrically connected to a group of input channels of the high-speed multiplexer; the output signal of the magnetic field sensor is electrically connected to another group of input channels of the high-speed multiplexer; the output channel of the high-speed multiplexer is electrically connected to the data acquisition card; the data acquisition card is connected to the terminal device through a wireless network; Electrically connect the input terminal of the power switch to be tested to the programmable current source, Contact the current probe to clamp the output terminal of each contact of the power switch to be tested, and place a corresponding magnetic field sensor near each current probe, so as to deploy the switch multiplexing test fixture for the target power switch.

[0035] In an embodiment of the present invention, a DC programmable current source with an output capacity of at least 500 A, a ripple factor lower than 0.1%, and capable of being remotely programmed and controlled through a standard command set (such as SCPI) is selected. Secondly, a high-speed multiplexer module based on solid-state relay technology with a switching time lower than 1 microsecond and at least 8 differential input channels is selected, such as a module installed in a PXI chassis. At the same time, a multi-channel data acquisition card (DAQ) with a 16-bit resolution, a sampling rate not lower than 1 MS / s, and synchronous sampling ability is selected, also installed in the PXI chassis. Prepare several (the number is equal to the number of power switch contacts to be measured, such as 3) open-loop or closed-loop Hall effect current probes with a measurement range covering the expected test current and a bandwidth not lower than 1 MHz, and equip the same number of three-axis magnetic field sensors with sufficient sensitivity to detect the magnetic field transients generated by the on-off of the current near the switch contacts. During assembly, connect the BNC output signal cables of the current probes to channels 1 to channel N (N is the number of contacts) of the high-speed multiplexer through low-noise coaxial cables. Connect the signal output cables of the magnetic field sensors (usually including X, Y, Z axis signals) to channels N + 1 to channel M of the high-speed multiplexer through shielded twisted pairs. The common output channel of the high-speed multiplexer is connected to the analog input port AIN0 of the data acquisition card through a coaxial cable with high shielding performance. The data acquisition card is configured and 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). This wireless network is also connected to an industrial tablet or laptop computer running a specific data receiving and analyzing program as a terminal device. Select a flexible copper cable with a cross-sectional area sufficient to carry at least 250 A current (considering a margin) and an insulation class meeting the test voltage requirements, and crimp high-conductivity copper lugs (wire lugs) at both ends of the cable. Check the input terminals of the contactor to be measured (such as marked as L1, L2, L3) and the positive and negative output terminals of the programmable current source to ensure they are clean and free of oxidation. Use a torque wrench to firmly connect the copper lug at one end of a cable to the positive output terminal of the programmable current source according to the torque specified by the contactor and current source manufacturers, and connect the other end to the L1 input terminal of the contactor to be measured. For a three-phase switch, if the test objective is the single-phase current-carrying capacity or multi-phase independent testing, only connect the input of one phase; if it is necessary to simulate a three-phase load, connect the L1, L2, L3 terminals to the current source output in parallel or series according to the test requirements (or use a three-phase power supply, but it is described as a single current source connection here). Connect another cable of the same specification, with one end connected to the negative (or return) output terminal of the programmable current source and the other end connected to the return end of the load circuit that matches the output end of the contactor to be measured or directly connected to the expected common return end of the contactor to avoid additional voltage drops and heat generation during subsequent high-current tests.Select the first Hall effect current probe, open its jaws, and precisely wrap and clamp the wire or busbar connected to the T1 output terminal. During operation, ensure that the wire is located in the central area of the probe's sensing window, the jaws are fully closed without gaps, and the probe body does not come into direct contact with the live conductor (relying on 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 at a position adjacent to the contact area of the T1 output terminal, approximately 5 to 10 millimeters away from the contact gap. The specific axis of the sensor (e.g., the Z-axis) should be roughly perpendicular to the expected current path or parallel to the contact movement direction to maximize the capture of the magnetic field characteristics of the switch operation and potential arc generation. Repeat this process, clamp the second current probe to the wire of the T2 output terminal, and fix the second magnetic field sensor near the T2 contact; then clamp the third current probe to the wire of the T3 output terminal, and fix the third magnetic field sensor near the T3 contact. Ensure that each current probe is paired with its corresponding magnetic field sensor to form a one-to-one measurement unit. The signal cables of all sensors should be properly organized and connected to the corresponding input channels reserved on the high-speed multiplexer before. After deployment, check the fixation firmness of all sensors to avoid displacement under the mechanical vibration during switch operation.

[0036] Preferably, the processing of the contact pulse signal for the power switch to be tested in step S1 includes: Extract the switch rated current and the number of contacts according to the power switch to be tested; Set the current pulse amplitude for each contact based on the switch rated current and the number of contacts; Based on the current pulse amplitude, process the duration and interval time of the safety test current pulse through the contact current pulse amplitude to obtain the test pulse duration and interval time; Perform current pulse subsequence processing according to the contact current pulse amplitude, test pulse duration, and interval time, and then sort the contact pulse signals to generate an independent contact pulse excitation sequence.

[0037] In an embodiment of the present invention, taking a three-pole molded case circuit breaker as the test model, the operator first visually inspects the nameplate on the side or front of the circuit breaker body. For example, the nameplate clearly marks "In = 400A", and based on this, it is determined that the rated current of this power switch is 400 amperes. At the same time, observe the wiring terminals of the circuit breaker or consult its product data sheet to confirm that the circuit breaker has three independent phase wire paths L1, L2, and L3, so the number of its contacts is 3 (excluding auxiliary contacts). According to the obtained rated current (400A) and the number of contacts (3), use the parameter calculation logic built into the test device to determine the peak value of the test current pulse applied to each contact. The setting logic follows a preset rule: the peak test current applied to each contact is 120% of its rated current. The control unit of the test device (such as a controller based on an embedded processor) performs this calculation: target pulse amplitude = rated current × 1.20 = 400A × 1.20 = 480A. Since the test objective is to evaluate the performance of a single contact or perform independent excitation between contacts, this 480A pulse amplitude value is set as the target peak value of the current pulse to be subsequently applied to each contact under test (T1, T2, T3, usually applied sequentially or controlled through a specific routing). Based on the current pulse amplitude set in the previous step, and the thermal characteristic parameters of the contact material obtained from the data sheet of the switch under test or through pre-experiments (for example, the allowable temperature rise and thermal time constant of copper alloy contacts), the test control application performs a thermal energy limit calculation. Using the I²t (current squared multiplied by time) criterion, set the upper limit of the energy injected per single pulse. For example, limit the instantaneous temperature rise of the contact caused by a single pulse not to exceed 10% of its long-term operating temperature rise limit. To meet this temperature rise limit, the maximum allowable pulse duration is 125 milliseconds. At the same time, to ensure that the contacts have enough time to cool between pulses and avoid heat accumulation, set the pulse interval time (2500). The interval time is set based on the average power limit. For example, it is required that the average power of the pulse sequence does not exceed 5% of the rated loss power of the switch. Define a basic "current pulse subsequence unit", which contains a complete pulse event: the current rises from 0A to 480A, maintains for 125ms, then drops to 0A, followed by a 2500ms current-free interval period. Then, the sequence generator module of the test device creates a repeating subsequence according to a preset test strategy (for example, applying 10 pulses to each contact to evaluate its stability). For example, generate a list containing 10 of the above "current pulse subsequence units" to form a "single contact test block". Finally, perform sorting on the contact pulse signals to generate the final "independent contact pulse excitation sequence". One sorting method is sequential testing: assign the "single contact test block" to each contact in sequence.The specific sequence instruction stream 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 instruction sequence is formatted into a command list recognizable by the programmable current source and (if any) output switching matrix, stored in the memory of the test controller, and is ready to be issued in sequence during the test execution phase to drive the hardware to generate precise and independent pulse excitations for each contact.

[0038] Preferably, in step S1, the switching multiplexing test fixture is controlled by an independent contact pulse excitation sequence, and a contact current pulse excitation test is performed on the power switch to be tested: The terminal device sends the independent contact pulse excitation sequence to the switching multiplexing test fixture for control signal encoding to obtain a pulse excitation control signal; The test status of the switching multiplexing test fixture is judged to obtain a test status flag; Based on the test status flag, the switching multiplexing test fixture is controlled by the pulse excitation control signal to perform a contact current pulse excitation test, and the current probe, magnetic field sensor, and switching power supply 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 supply voltage signal 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.

[0039] In an embodiment of the present invention, through its wireless network interface (such as a Wi-Fi module), this JSON sequence data packet is sent to the preset IP address and port number of a switch multiplexing test fixture (specifically, an embedded controller within a PXI chassis) using the TCP / IP protocol stack. The firmware or dedicated control logic running on the PXI controller receives the data packet, parses the JSON structure, and extracts the target contacts, current amplitude, duration, interval time, and number of repetitions for each excitation step. Then, the control logic "encodes" these high-level parameters into a low-level instruction set specific to the hardware. For example, converting "contact: T1" into a specific register write value or digital I / O signal pattern that configures the high-speed multiplexer to switch to channels 1 and (N + 1) connected to the T1 sensor; before performing any high-current pulses, the PXI controller of the test fixture must perform a series of strict self-checks and status confirmations. First, the controller sends a query command to the programmable current source via the PXI backplane or communication bus (such as GPIB, Ethernet) to confirm that the current source has no internal faults, is not in an overheat or overload protection state, and its output is currently in the OFF state. Second, the controller detects the status of the high-speed multiplexer module to confirm that it has correctly responded to the configuration command and there is no hardware fault report. Third, the controller checks the status of the data acquisition card (DAQ) to confirm that its self-check has passed, the clock is stable, and the communication with the controller is normal. In addition, the controller also reads the status of the external safety interlock signal connected to its digital input port, such as checking whether the test protection door is closed properly (the corresponding input is high level). The controller synthesizes 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, a boolean variable or a specific register bit is set in the internal memory, denoted as "Test_Ready_Flag", with a value of TRUE (or 1). If any one of the checks fails, "Test_Ready_Flag" is set to FALSE (or 0), and the execution of subsequent pulse excitations is blocked, while specific error messages are displayed on the terminal device interface. When and 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 the T1 contact, 480A, 125ms): the controller first sends an instruction to configure the high-speed multiplexer, connecting its output to the inputs of the current probe corresponding to the T1 contact (such as channel 1) and the magnetic field sensor (such as channel N + 1).Meanwhile, the controller configures the data acquisition card (DAQ), sets its sampling rate to 1 MS / s, sets the acquisition duration (e.g., 200 ms to cover before and after the pulse), specifies the channels to be acquired (the MUX output channels, and the channel connected to another for monitoring the power supply voltage, such as 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 (such as INITiate: IMMediate), and at the same exact moment (or achieve nanosecond-level synchronization through 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 performs analog-to-digital conversion on 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 sampling points in 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 complete, the controller reads the data stored in the DAQ to obtain the original excitation current signal (from the current probe) of the T1 contact, the original electromagnetic signal (from the magnetic field sensor), and the time series array of the power supply voltage signal. Repeat the execution strictly according to the sequence instructions, repeat a specified number of times for T1, then switch the MUX configuration to the T2-related channels, and then perform the pulse and acquisition for T2 until all pulse tests for all contacts are completed. Send this data packet to the network port listened to by the test control application running on the terminal device using the TCP protocol. After the application on the terminal device receives the data packet, it first parses the data of each signal channel according to the metadata. Then perform "digital signal conversion": convert the original integer values (ADC counts) acquired by the DAQ into floating-point values with physical units according to the pre-calibrated sensor sensitivity, the voltage range of the DAQ, and the gain settings.

[0040] Preferably, step S2 includes the following steps: Step S21: Perform current calibration processing on each contact excitation current signal in the contact group pulse response data to obtain the calibrated current data for each contact; Step S22: Aggregate the contact excitation currents of the calibrated current data for each contact to obtain the shunt data for each contact; Step S23: Calculate the current change rate of each contact according to the shunt data of each contact, and generate the current change rate curve for each contact; Step S24: Identify the jump edge interval according to the current change rate curve of each contact to obtain the jump edge interval data for each contact; among them, the jump edge interval identification includes rising edge, steady state section, and falling edge identification; Step S25: Calculate the maximum jump rate of each contact for the data in the contact jump edge interval; Step S26: Calculate the jump time of each contact according to the data in the contact jump edge interval; Step S27: Extract the jitter value of each contact jump edge from the current change rate curve of each contact based on the data in the contact jump edge interval; Step S28: Combine the features of the maximum jump rate of each contact, the jump time of each contact, and the jitter value of each contact jump edge to obtain the contact jump feature data.

[0041] In the embodiments of the present invention, an array of original current signal time series collected during all pulse excitations for the first contact (e.g., T1) is extracted from the "contact group pulse response data". 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, based on the 10-millisecond interval before the trigger signal timestamp. All current sampling point values within this interval are extracted, and the arithmetic mean of these sampling points is calculated. This mean value is the zero offset for this measurement. Each sampling point value in the entire current data array of this pulse is subtracted by the calculated zero offset. This zero calibration process is repeated for all the remaining pulses of contact T1. Subsequently, in the same manner, independent zero offset calculations and subtraction calibrations are performed on the pulse excitation current signals of each pulse for the second contact (T2) and the third contact (T3) in turn. The finally obtained data set is the current data after zero calibration for all contacts and all pulses, denoted as "post-calibration current data for each contact". The "post-calibration current data for each contact" for the first contact (T1) includes, for example, 10 calibrated current time series arrays obtained from 10 pulse excitation tests on it. These 10 time series are precisely aligned based on the pulse trigger time points. A new empty array is created, with the same length as the time series length of a single pulse. For the first time point in the new array, the arithmetic mean of the current values at this time point in the 10 original arrays 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 at this time point in the 10 original arrays is calculated and stored in the second position of the new array. And so on until all time points are processed. The average current time series thus obtained is the "aggregated current data" for contact T1. In exactly the same way, the 10 calibrated current time series for contact T2 are aligned and averaged point by point to obtain the aggregated current data for T2; then the 10 calibrated current time series for contact T3 are processed to obtain the aggregated current data for T3. These three aggregated current time series are collectively referred to as "shunt data for each contact" (here "shunt" is understood as differentiating data for different contacts), which reflect 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). This sequence consists of current values at a series of discrete time points, with the time point interval being the sampling period of the data acquisition card (e.g., 1 microsecond). To calculate the current change rate (dI / dt), a first-order backward difference method is used: for the i-th point in the sequence (i starting from 1 to N - 1, where N is the sequence length), its corresponding current change rate 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 T1 aggregated current sequence (usually all points except the first point), resulting in a new time series, namely the "rate of change of current curve" of T1. Similarly, applying the backward difference method to the aggregated current data of T2 and T3 respectively generates the rate of change of current curves of T2 and T3. These three curves form the set of "rate of change of current curves for each contact". Determine a threshold for distinguishing significant changes from noise, for example, set to 10% of the absolute value of the maximum rate of change. Find the timestamp of the first point on the curve that exceeds the positive threshold, denoted as the start time of the rising edge. Then, find the timestamp of the first point that falls below the positive threshold after the peak of the rate of change, denoted as the end time of the rising edge. Subsequently, find the timestamp of the first point on the curve that is below the negative threshold (i.e., less than -threshold), denoted as the start time of the falling edge. Finally, find the timestamp of the first point that rises above the negative threshold (i.e., greater than -threshold) after the trough of the rate of change, denoted as the end time of the falling edge. Then, the time interval [start time of the rising edge, end time of the rising edge] is defined as the rising edge interval of T1. The time interval [start time of the falling edge, end time of the falling edge] is defined as the falling edge interval of T1. And the time interval [end time of the rising edge, start time of the falling edge] is defined as the steady state segment interval of T1. Record these three intervals (each containing the start and end timestamps). Perform the exact same threshold judgment and interval search logic on the rate of change of current curves of T2 and T3, respectively obtaining the rising edge, steady state segment, and falling edge interval data of T2 and T3. Using the "jump edge interval data" of the first contact (T1) obtained in the previous step, that is, the rising edge interval [start time of the rising edge, end time of the rising edge] and the falling edge interval [start time of the falling edge, end time of the falling edge]. Return to the "rate of change of current curve" of T1 and find the maximum value within the time period from the start time of the rising edge to the end time of the rising edge in this curve. This maximum value is the "maximum rising jump rate" of T1. Similarly, find the minimum value (usually a negative value) of the rate of change of current curve within the time period from the start time of the falling edge to the end time of the falling edge. This minimum value is the "maximum falling jump rate" of T1 (representing the fastest falling speed). Record these two rate values (unit: amperes per second). For T2 and T3, also find the maximum and minimum values from their respective rate of change of current curves within their corresponding rising edge and falling edge intervals, obtaining the maximum rising and falling jump rates of T2 and T3. The set of these maximum rate values for all contacts is what is sought. The rise time is usually defined as the time interval required for the current to rise from 10% of its steady state low value to 90%. The fall time is defined as the time interval required for the current to fall from 90% of its steady state high value to 10%.The specific calculation method is as follows. Within the rising edge interval, find two time points where the current values are respectively close to 10% and 90% of the steady-state low value, and calculate the time difference between these two time points, which is the rise time. Similarly, within the falling edge interval, find two time points where the current values are respectively close to 90% and 10% of the steady-state high value, and calculate the time difference between these two time points, which is the fall time. Record the rise time and fall time of each contact. For the calibrated current data of each pulse excitation and its corresponding rate of change curve. For example, for 10 pulse excitations of the first contact (T1), independently execute the logic of step S24 for each excitation to obtain 10 sets of independent transition edge interval data, namely 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 these 10 rising edge start time values and calculate their standard deviation, which is defined as the "rising edge start jitter value" of T1. Similarly, calculate the standard deviation of the 10 rising edge end time values to obtain the "rising edge end jitter value"; calculate the standard deviation of the 10 falling edge start time values to obtain the "falling edge start jitter value"; calculate the standard deviation of the 10 falling edge end time values to obtain the "falling edge end jitter value". Record these four jitter values (usually in nanoseconds or microseconds) as the transition edge jitter characteristics of T1. For T2 and T3, repeat this complete process: that is, calculate the rate of change, identify the intervals, collect four types of time points for their respective 10 independent pulse responses, 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), transition time (rise time and fall time), and transition edge jitter value (rising edge and falling edge) for each contact, combine these independent characteristic parameters to form contact transition characteristic data that can comprehensively describe the dynamic characteristics of the contact. For each contact, its contact transition characteristic data can include a characteristic vector that contains multiple values such as its maximum rising edge transition rate, maximum falling edge transition rate, rise time, fall time, rising edge jitter value, and falling edge jitter value.

[0042] Preferably, step S3 includes the following steps: Step S31: Judge whether there is an event of too fast or too slow transition for each contact according to the maximum transition rate of each contact to obtain the rate anomaly flag of each contact; wherein, when the maximum transition rate of the contact exceeds 500 A / s or is lower than 50 A / s, it is determined that the contact has a transition rate anomaly; Step S32: Judge whether there is an event of too long or too short transition for each contact according to the maximum transition rate of each contact to obtain the time anomaly flag of each contact; wherein, when the transition duration of the contact exceeds 5 ms or is lower than 0.5 ms, it is determined that the contact has a transition time anomaly; Step S33: Determine whether there is a jump jitter anomaly event for each contact by judging the jitter value of each contact's jump edge through a preset jitter threshold, and obtain the jitter anomaly flag for each contact; among them, when the jump time deviation between two adjacent pulses of the contact jump edge exceeds 15%, it is determined that there is a jump jitter anomaly for the contact. Step S34: Based on the rate anomaly flag of each contact, the time anomaly flag of each contact, and the jitter anomaly flag of each contact, conduct a comprehensive evaluation of the contact anomaly jump event, and generate the evaluation data of the jump anomaly event for each contact; among them, when a certain contact simultaneously meets the conditions of any two or more anomaly flag conditions, or at least 5 times of the same type of anomaly flag appears in 10 consecutive tests of the contact, it is determined that a serious jump anomaly event occurs for the contact.

[0043] In the embodiments of the present invention, the "maximum jump rate of each contact" in the "contact jump feature data" is used for evaluation. Take the record of the first contact (for example, T1), and extract its "maximum rising rate" value and "maximum falling rate" value (take the absolute value). Compare the "maximum rising rate" with a preset upper threshold of 500 amperes per second (A / s) and a lower threshold of 50 amperes per second (A / s). If the "maximum rising rate" is greater than 500 A / s or less than 50 A / s, it is determined that there is an abnormal rising rate for T1. Similarly, compare the absolute value of the "maximum falling rate" 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 there is an abnormal falling rate for T1. Set a boolean variable "T1 rate anomaly flag", and as long as the rising rate or the falling rate (or both) is determined to be abnormal, set this flag to TRUE; otherwise, set it to FALSE. 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, then the T1 rate anomaly flag is set to TRUE due to the excessive rising rate. Repeat this comparison process for the second contact (T2) and the third contact (T3), and respectively determine and record their respective "rate anomaly flags" (T2 rate anomaly flag, T3 rate anomaly flag). Extract the "rise time" value and "fall time" value from the record of the first contact (T1). Compare the "rise time" with a preset time upper threshold of 5 milliseconds (ms) and a time lower threshold of 0.5 milliseconds (ms). If the "rise time" is greater than 5 ms or less than 0.5 ms, it is determined that there is an abnormal rise time for T1. Similarly, compare the "fall time" with 5 ms and 0.5 ms. If the "fall time" is greater than 5 ms or less than 0.5 ms, it is determined that there is an abnormal fall time for T1. Set a boolean variable "T1 time anomaly flag", and as long as the rise time or the fall time (or both) is determined to be abnormal, set this flag to TRUE; otherwise, set it to FALSE. For example, if the rise time of T1 is 0.3 ms and the fall time is 2 ms, then the "T1 time anomaly flag" is set to TRUE due to the too short rise time. Repeat this comparison process for the second contact (T2) and the third contact (T3), and respectively determine and record their respective "time anomaly flags" (T2 time anomaly flag, T3 time anomaly flag). For the same contact, in two consecutive current pulse excitation tests, calculate its rise time or fall time respectively. If the deviation between the two measured rise times exceeds 15% of their average value, or the deviation between the fall times exceeds 15% of their average value, it is determined that there is a jump jitter anomaly for this contact, and a jitter anomaly flag is assigned to this contact.For example, in the first test, the rise time of a certain contact is 1 millisecond, and in the second test, it is 1.3 milliseconds. The average value is 1.15 milliseconds, the deviation is 0.3 milliseconds, and the deviation rate is approximately 0.3 / 1.15. 100% ≈ 26%, exceeding the threshold of 15%. Therefore, this contact will be marked as having a rising edge jitter anomaly. The evaluation rules are as follows: If a certain contact simultaneously meets any two or more anomaly flag conditions in one test (for example, there are both too fast transitions and transition timeouts, or there are both too slow transitions and jitter anomalies), then it is determined that a serious transition anomaly event has occurred for this contact. In addition, considering accidental factors that may cause anomalies in a single test, judgment conditions based on multiple test results are also set: If a certain contact has the same type of anomaly flag in at least 5 out of 10 consecutive current pulse excitation tests (for example, there are 5 or more rate anomaly flags of too fast transitions in 10 consecutive tests), it is also determined that a serious transition anomaly event has occurred for this contact. For contacts determined to have a serious transition anomaly event, corresponding evaluation data will be generated, such as recording the contact number, the type of anomaly that occurred (including single multiple anomalies and multiple repeated anomalies), and the number of tests in which the anomaly occurred, etc. For example, if the "rate anomaly flag" of T1 = TRUE, the "time anomaly flag" = TRUE, and the "jitter anomaly flag" = FALSE, then since condition one (two flags are TRUE) is met, T1 is determined to be "seriously abnormal". Another example is that all three aggregated flags of T2 are FALSE, but in 10 pulse tests, there are 6 times of "time anomalies" (for example, the pulse duration is too short). Then, although the aggregated data seems normal, due to meeting condition two, T2 is still determined to be "seriously abnormal". The same comprehensive evaluation logic is also executed for T3. The final generated data set containing the evaluation results of T1, T2, and T3 (for example: "T1: Seriously abnormal, T2: Seriously abnormal, T3: Normal") is the "evaluation data of contact transition anomaly events".

[0044] Preferably, step S4 includes the following steps: Step S41: Calculate the total switch current based on the shunt data of each contact; Step S42: Calculate the equivalent total resistance of the total switch current through the power supply voltage signal in the contact group pulse response data to generate equivalent total resistance data; Step S43: Perform iterative distribution of the instantaneous contact resistance of each contact based on the equivalent total resistance data and the shunt data of each contact to obtain the instantaneous resistance sequence of each contact; Step S44: Calculate the average resistance of each contact based on the instantaneous resistance sequence of each contact; Step S45: Calculate the standard deviation of the resistance of each contact based on the instantaneous resistance sequence of each contact and the average resistance; Step S46: Calculate the resistance volatility of each contact in the power switch to be measured based on the average resistance and the standard deviation of each contact resistance, and generate the contact resistance volatility.

[0045] In the embodiments of the present invention, for parallel contacts operating at the same moment, their currents will be superimposed. Therefore, at each sampling moment, the instantaneous current values in the shunt data of all closed contacts are added together to obtain the total current value flowing through the power switch at that moment. The total current values calculated at each sampling moment are arranged in chronological order to obtain the time series of the total switch current. For example, in a certain test stage of a double-pole double-throw switch, assuming that the two output contacts corresponding to its two blades are simultaneously closed to conduct current, if at a specific sampling moment, the current value of the first contact is 2.5 amperes and the current value of the second contact is 2.3 amperes, then the total current of the switch at that moment is 2.5 + 2.3 = 4.8 amperes. Performing this summation operation for all sampling moments yields the complete total switch current data. Use the time series of the "total switch current" obtained in step S41. Determine the steady-state interval of the current pulse, and this interval information can be obtained from the "steady-state segment interval" in the "edge transition interval data of each contact" obtained in step S24 (for example, select the intersection of the steady-state intervals of all contacts). Create a new time series array to store the equivalent total resistance. Only within the identified steady-state time interval, perform the following calculations for each time point t: Read the power supply voltage value V(t) at that moment (it is necessary to confirm that this voltage is the accurately measured voltage drop across the switch. If not, compensation is required or differential voltage measurement is used) and the total switch current value I_total(t). Apply Ohm's law to calculate the instantaneous equivalent total resistance R_total(t) = V(t) / I_total(t). Store the calculation result R_total(t) in the corresponding time point position of the equivalent total resistance array. Repeat this division operation for all time points within the steady-state interval. If I_total(t) is close to zero at some points, anti-division-by-zero processing needs to be added (for example, calculate only when the current is greater than a certain threshold). The resulting resistance time series array within the steady-state interval is the "equivalent total resistance data". Assume that in the initial state, the contact resistances of all parallel contacts are equal. At each sampling moment, based on the equivalent total resistance and the shunt current values of each contact at that moment, use the parallel resistance calculation formula to perform back-calculation to preliminarily estimate the instantaneous resistance of each contact. Then, based on the preliminarily estimated contact resistance values, recalculate the shunt current of each contact and compare it with the actually measured shunt current. If there is a difference, adjust the resistance estimate value of each contact according to the magnitude of the difference, and perform the calculation and comparison of the shunt current again. Repeat this iterative process until the error between the calculated shunt current and the actually measured shunt current is less than a certain preset threshold or the set maximum number of iterations is reached. The resulting sequence of resistance estimate values of each contact at each sampling moment is the instantaneous resistance sequence of each contact. For the instantaneous resistance sequence R_T1(t) of the first contact T1, calculate the arithmetic mean of all resistance values in this sequence.The specific operation is: add 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 in the steady-state interval, and N is the number of points in the steady-state interval. The calculated single value is the "average resistance" of contact T1. In exactly the same way, the arithmetic mean of the instantaneous resistance sequence R_T2(t) of T2 is calculated to obtain the "average resistance" of T2. Then the arithmetic mean of the instantaneous resistance sequence R_T3(t) of T3 is 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 sequence, calculate the square of its difference from the average value. Sum up all the square differences, then divide by the total number of sampling points minus one (as an unbiased estimate), and finally take the square root of the result to obtain the standard deviation of the resistance of the contact. The larger the standard deviation, the greater the fluctuation of the instantaneous resistance value of the contact around its average value, and the more unstable the contact. For example, if the instantaneous resistance value of a contact is high and low, and deviates greatly from its average value, then the standard deviation of the resistance of the contact will be relatively large. The resistance standard deviation is an important indicator for judging whether there are transient faults such as poor contact and jitter at the contact. For the first contact T1, calculate its resistance fluctuation rate. The formula is: Fluctuation rate_T1=(Standard deviation_T1 / Average resistance_T1) 100%. The calculation result is expressed as a percentage. For example, if the average resistance_T1=0.5 milliohms, the standard deviation_T1=0.05 milliohms, then the fluctuation rate_T1=(0.05 / 0.5) 100%=10%. This 10% is the "resistance fluctuation rate" of contact T1. For the second contact T2, use its average resistance_T2 and standard deviation_T2, apply the same formula to calculate, and get the "resistance fluctuation rate" of T2. For the third contact T3, use its average resistance_T3 and standard deviation_T3 to calculate, and get the "resistance fluctuation rate" of T3. The final generated set of these three percentage values ​​{fluctuation rate_T1, fluctuation rate_T2, fluctuation rate_T3} is the "contact resistance fluctuation rate" data.

[0046] As an example of the present invention, refer to Figure 2 As shown, Figure 1 Detailed implementation steps of step S5 in the flowchart, in this example, step S5 includes: Step S51: grouping abnormal contacts of the power switch to be tested according to the evaluation data of abnormal contact jump events to obtain a switch abnormal contact group; In the embodiment of the present invention, each contact in the power switch is analyzed to identify the abnormal contacts. The evaluation data records information such as abnormal jump rate, abnormal jump time, and abnormal jump jitter that occur for each contact. All contacts evaluated as having serious jump abnormal events are classified into a set to form a switch abnormal contact group. For example, if a four-contact power switch is evaluated in step S3, and contacts 1 and 3 are determined to have serious jump abnormal events (too slow jump and excessive jitter), while the jump characteristics of contacts 2 and 4 are normal, then the switch abnormal contact group includes contacts 1 and 3.

[0047] 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 the contact magnetic field abnormal mode; In the embodiment of the present invention, the magnetic field sensor time series data (including X, Y, and Z axis components) corresponding to T1 and T3 after digital signal conversion is extracted from the original "contact group pulse response data". For the magnetic field signal of T1, within the jump edge interval (rising edge and falling edge, interval information from S24), the fast Fourier transform (FFT) is used to calculate its spectrum. The obtained spectrum is compared with the spectrum of a normal contact (such as T2) in the same interval. If it is found that the energy of the spectrum of T1 in a specific high-frequency band (such as above 10 kHz) is significantly higher than that of T2 (such as exceeding 20 decibels), then the magnetic field abnormal mode of T1 is recorded as "enhanced switch transient high-frequency magnetic field radiation". For the magnetic field signal of T3, the steady-state conduction interval (interval information from S24) is mainly analyzed. The root mean square (RMS) value or peak-to-peak value of the magnetic field signal in this interval is calculated. If the RMS value of T3 is significantly higher than the RMS value of T2 (such as exceeding the set threshold of 0.5 millitesla), or the signal waveform shows unexpected continuous fluctuations or intermittent spikes with an amplitude exceeding the noise level, then the magnetic field abnormal mode of T3 is recorded as "magnetic field instability during steady-state conduction".

[0048] Step S53: Based on the contact magnetic field abnormal mode, contact resistance volatility, and evaluation data of each contact jump abnormal event, perform single-contact fault type rule matching to generate single-contact fault type data; In the embodiment of the present invention, the abnormal contacts determined by step S51 (such as T1, T3) are combined with the specific trigger conditions of the "severe jump abnormal event" in S34 (whether it is a combination of rate abnormality, time abnormality or jitter abnormality), the value of the "contact resistance volatility" calculated by S46, and the "contact magnetic field abnormal mode" determined by S52. These pieces of information are input into a pre-constructed fault diagnosis rule base (such as a set of expert rules stored in an if-then form). For example, for contact T1: if the evaluation result of T1 is a "severe jump abnormal event" (the trigger conditions include "too short jump time" and "too fast jump rate") and the resistance volatility of T1 is greater than 15% and the magnetic field abnormal mode of T1 is "enhanced high-frequency magnetic field radiation during switch transient", otherwise it is determined that the fault type of T1 is "contact ablation or severe wear". For contact T3: if the evaluation result of T3 is a "severe jump abnormal event" (the trigger conditions include "jump jitter abnormality") and the resistance volatility of T3 is between 5% and 15% and the magnetic field abnormal mode of T3 is "magnetic field instability during steady-state conduction", otherwise it is determined that the fault type of T3 is "insufficient contact pressure of the contact or aging of the spring mechanism". The fault types (such as "contact ablation or severe wear", "insufficient contact pressure") matched by each abnormal contact are recorded to form "single-contact fault type data".

[0049] Step S54: Evaluate the health of the power switch to be tested through the single-contact fault type data, and then perform overall switch fault type processing and fault location to obtain power switch fault data.

[0050] In the embodiment of the present invention, the evaluation rules are as follows: if all contacts are "normal", the health is "excellent"; if there are "minor abnormalities" but no contacts with "severe jump abnormal events", the health is "acceptable"; if there is one contact with a "severe jump abnormal event", the health is "needing attention"; if there are two or more contacts with "severe jump abnormal events", or there is a specific severe fault type (such as "risk of contact welding"), the health is "poor / urgent repair required". 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 multi-contact faults, including contact ablation (T1) and insufficient contact pressure (T3)". Finally, perform "fault location": clearly point out the specific contact positions where the faults occur. For example, directly list the identifiers of the abnormal contacts ["T1", "T3"]. Integrate the health evaluation result, the overall fault type description and the fault location information into a structured report object or file, and this object or file is the "power switch fault data".

[0051] Preferably, step S52 is specifically as follows: Process the magnetic field intensity in the three-axis orthogonal directions according to the electromagnetic signals of each contact in the contact group pulse response data to obtain the three-axis magnetic field intensity data of the contacts; Obtain the spatial position of the magnetic sensor; map the spatial position of the magnetic sensor and the three-axis magnetic field intensity data of the contacts in space, and then calculate the magnetic field gradient to obtain the magnetic field gradient distribution data; Calculate the modulus value of the gradient vector according to the magnetic field gradient distribution data, and then extract the position of the maximum vector modulus value to obtain the maximum magnetic field gradient data; Analyze the magnetic field center offset of the abnormal contact group of the switch through the magnetic field gradient distribution data to obtain the magnetic field offset of the abnormal contact; Perform processing on the abnormal magnetic field mode of the contacts according to the maximum magnetic field gradient data, the magnetic field offset of the abnormal contacts, and the magnetic field gradient distribution data to obtain the abnormal magnetic field mode of the contacts.

[0052] In the embodiment of the present invention, if a three-axis magnetic field sensor is used, when collecting the electromagnetic signals of the contacts, time series of the magnetic field intensity components in three mutually orthogonal directions, namely X, Y, and Z, will be obtained synchronously. The data processing unit needs to record and organize the magnetic field signals in these three directions collected for each contact to obtain the three-axis magnetic field intensity data corresponding to each contact at each sampling moment during the entire test process. It is obtained by precise measurement during fixture design or by using a three-dimensional measurement device after deployment. After obtaining the three-dimensional coordinates (x, y, z) of each magnetic sensor, these spatial position information is associated with the three-axis magnetic field intensity data (Bx, By, Bz) of the corresponding contacts at each sampling moment to establish a spatial mapping relationship. Then, based on the change in the magnetic field intensity between adjacent sampling points and the relative position relationship between the magnetic sensor and the contacts, the gradient of the magnetic field in space is calculated. The magnetic field gradient is a vector that describes the rate and direction of the change of the magnetic field intensity in space. For a gradient vector (Gx, Gy, Gz), its modulus value is . Calculate the modulus of all calculated gradient vectors to obtain the distribution of magnetic field gradient modulus. Then, find the largest value from these moduli and the spatial position corresponding to the maximum value. This largest magnetic field gradient modulus reflects the area where the magnetic field strength changes fastest, which is usually related to the area with the largest current density or the location of arc discharge. The position of the maximum vector modulus indicates the spatial point where the change is most drastic. Use its magnetic field gradient distribution data for analysis. Under normal circumstances, the center of the magnetic field generated when the contact is closed or opened should roughly coincide with the physical position of the contact. When there is a fault in the contact, such as poor contact or eccentric wear, the distribution of the current will change, causing the center of the magnetic field to shift. By analyzing the magnetic field gradient distribution data, the center position of the magnetic field strength can be determined (for example, it can be defined as the center of the area with the largest magnetic field gradient vector modulus). Then, calculate the distance and direction deviation between this magnetic field center and the physical center position of the contact to obtain the abnormal contact magnetic field offset. Integrate the "maximum magnetic field gradient data" (maximum gradient value and its position), "abnormal contact magnetic field offset" (offset vector of each abnormal contact) and the overall "magnetic field gradient distribution data". Apply a preset set of discrimination rules: Rule 1: If the "maximum magnetic field gradient value" is significantly higher than the baseline value (for example, more than 3 times the average gradient of a normal contact) and its "position" is close to the physical edge or gap area of ​​an abnormal contact, otherwise the abnormal magnetic field pattern of the contact is marked as "local current density is too high or edge arc". Rule 2: If the modulus of the "magnetic field offset" vector of an abnormal contact is greater than a threshold (for example, 2 mm) or its direction points to an unexpected structural area, otherwise the abnormal magnetic field pattern of the contact is marked as "main current path offset or contact point eccentricity". Rule 3: 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 area, otherwise its pattern is marked as "diffuse current distribution or poor contact". Rule 4: If combined with time series analysis (return to the data in step 1), the gradient shows abnormal high-frequency oscillation or lasts too long at the moment of switch switching, otherwise it is marked as "abnormal switching 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 matches its magnetic field characteristics, such as "T1: edge arc", "T3: main current path deviation". These label sets constitute the final "contact magnetic field abnormality pattern" data.

[0053] Preferably, the present invention further 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: A switching pulse test module is used to deploy a switching multiplexing test fixture for the power switch to be tested; perform contact pulse signal processing on the power switch to be tested to generate an independent contact pulse excitation sequence; control the switching 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 synchronously collect contact group pulse response data; A contact feature analysis module is used to aggregate contact excitation currents based on the contact group pulse response data to obtain shunt data for each contact; analyze contact transition features based on the shunt data for each contact to obtain contact transition feature data; A contact abnormal transition evaluation module is used to evaluate contact abnormal transition events based on the contact transition feature data to generate evaluation data for each contact transition abnormal event; A resistance fluctuation analysis module is used to analyze the contact resistance volatility based on the contact group pulse response data to generate the contact resistance volatility; A comprehensive fault diagnosis module is used to analyze the abnormal contact magnetic field based on the contact group pulse response data to obtain the abnormal contact magnetic field pattern; analyze the single-contact fault type based on the abnormal contact magnetic field pattern, the contact resistance volatility, and the evaluation data for each contact transition abnormal event to obtain the power switch fault data.

[0054] The present invention realizes independent excitation and response measurement of each parallel contact in the power switch by introducing a switching multiplexing test fixture and contact pulse signal processing. Compared with the traditional holistic test method, the present application can accurately quantify the state of a single contact and avoid the problem of signal aliasing of multiple contacts. Through the aggregated analysis of the contact group pulse response data, not only can the shunt situation of each contact be quantified and its current sharing characteristics be evaluated, but also abnormal current distribution problems caused by potential poor contact, oxidation, or mechanical wear of the contacts can be detected. In addition, based on the evaluation of the contact transition features, abnormal transition events of a single contact at the moment of opening and closing can be further identified, so as to detect early faults affecting the switch reliability in advance. Through refined pulse excitation and response monitoring, dynamic current distribution analysis, microscopic transition feature evaluation, dynamic resistance stability consideration, and multi-source information fusion diagnosis, effective detection and accurate diagnosis of deep, dynamic, early, and hidden faults at the single-contact level of a multi-contact parallel power switch are realized, greatly improving the comprehensiveness, sensitivity, and accuracy of the test.

[0055] Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the application documents are intended to be encompassed by the present invention.

[0056] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power switch fault testing method, characterized in that: The following steps are involved: Step S1: deploying a switch multiplexing test fixture for 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 according to the contact group pulse response data to obtain the shunt data of each contact; performing contact jump characteristic analysis according to the shunt data of each contact to obtain the contact jump characteristic data; Step S3: evaluating abnormal contact jump events according to the contact jump characteristic data, and generating evaluation data of each abnormal contact jump event; Step S4: performing contact resistance fluctuation rate analysis according to the contact group pulse response data to generate contact resistance fluctuation rate; Step S5: analyzing the abnormal contact magnetic field based on the contact group pulse response data to obtain the abnormal contact magnetic field pattern; Single contact fault type analysis is performed 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.

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 group of input channels of the high-speed multiplexer; the output signal of the magnetic field sensor is electrically connected to another group of input channels of the high-speed multiplexer; the output channel of the high-speed multiplexer is electrically connected to the data acquisition card; the data acquisition card is connected to the terminal device through 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 contact-clamped to the output end of each contact of the power switch to be tested, and a corresponding magnetic field sensor is placed near each current probe, thereby deploying 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 according to the power switch to be tested; The current pulse amplitude of each contact is set based on the switch rated current and the number of contacts; 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; The current pulse subsequence is processed according to the contact current pulse amplitude, the test pulse duration and the interval time, and then the contact pulse signal is sorted to generate an independent contact pulse excitation sequence.

4. The power switch fault testing method according to claim 1, characterized in that: 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 a 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 mark, the switch multiplexing test fixture is controlled by the pulse excitation control signal to perform the 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 the digital signal is converted to obtain the contact group pulse response data.

5. The power switch fault testing method according to claim 1, characterized in that: 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 pulse response data of the contact point group 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 current shunt data of each contact; Step S23: Calculate the current change rate of each contact point according to the current shunting data of each contact point, and generate a current change rate curve of each contact point; Step S24: identifying the transition edge interval according to the current change rate curve of each contact point, and obtaining the transition edge interval data of each contact point; wherein the transition edge interval identification includes the rising edge, the steady state segment and the falling edge identification; Step S25: Calculate the maximum transition rate of each contact point based on the transition edge interval data of each contact point; Step S26: Calculate the transition time of each contact point according to 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, characterized in that: Step S3 includes the following steps: Step S31: judging whether each contact has an over-fast or over-slow jump event according to the maximum jump rate of each contact, and obtaining an abnormal rate mark 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 an abnormal jump rate; Step S32: judging whether each contact has a jump timeout or too short event according to the maximum jump rate of each contact, and obtaining a time abnormality mark of each contact; wherein, when the jump duration of the contact exceeds 5ms or is less than 0.5ms, it is determined that the contact has a jump time abnormality; Step S33: judging whether there is an abnormal jitter event at each contact by using a preset jitter threshold value to the jitter value of each contact jump edge, and obtaining an abnormal jitter flag of each contact; wherein, when the jump time deviation between two adjacent pulses of the contact jump edge exceeds 15%, it is determined that the contact has abnormal jitter; 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 abnormal event; wherein, when a certain contact simultaneously satisfies any two or more abnormal 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 the contact has a serious jump abnormal event.

7. The power switch fault testing method according to claim 1, characterized in that: Step S4 includes the following steps: Step S41: Calculate the total switch current according to the current distribution data of each contact point; Step S42: calculating the equivalent total resistance of the total switch current by 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 current shunting 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 according to the instantaneous resistance sequence of each contact point; Step S45: Calculate the standard deviation of each contact resistance according to 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 each contact resistance to generate the contact resistance fluctuation rate.

8. The power switch fault testing method according to claim 1, characterized in that: Step S5 includes the following steps: Step S51: grouping abnormal contacts of the power switch to be tested according to the evaluation data of abnormal contact jump events to obtain a switch abnormal contact group; Step S52: performing abnormal contact magnetic field analysis on the abnormal contact group of the switch through the electromagnetic signals of each contact in the contact group pulse response data to obtain the abnormal contact magnetic field mode; Step S53: performing single contact fault type rule matching based on the contact magnetic field abnormality mode, the contact resistance fluctuation rate and each contact jump abnormal event evaluation data to generate single contact fault type data; Step S54: Perform a health assessment on the power switch to be tested using the single contact fault type data, and then perform overall switch fault type processing and fault location to obtain the 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 intensity data of the contact point, and then calculating the magnetic field gradient to obtain the magnetic field gradient distribution data; Calculate the gradient vector modulus value according to the magnetic field gradient distribution data, and then extract the maximum vector modulus value position to obtain the maximum magnetic field gradient data; The magnetic field center offset of the switch abnormal contact group is analyzed by magnetic field gradient distribution data to obtain the magnetic field offset of the abnormal contact; The contact magnetic field abnormality mode 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 mode.

10. A power switch fault testing device, characterized in that: A control system is included for executing the power switch fault testing method as claimed in claim 1, the control system comprising: A switch pulse test module is used to deploy a switch multiplexing test fixture for the power switch to be tested; perform contact pulse signal processing on the power switch to be tested to generate an independent contact pulse excitation sequence; control the switch multiplexing test fixture through the independent contact pulse excitation sequence, and perform a contact current pulse excitation test on the power switch to be tested 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; A contact abnormal jump evaluation module is used to evaluate contact abnormal jump events according to contact jump characteristic data and generate evaluation data of each contact abnormal jump event; The resistance fluctuation analysis module is used to analyze the contact resistance fluctuation rate according to the contact group pulse response data and generate the contact resistance fluctuation rate; The comprehensive fault diagnosis module is used to analyze the abnormal contact magnetic field based on the contact group pulse response data to obtain the contact magnetic field abnormality pattern; and to analyze the single contact fault type according to 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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