High-voltage direct-current contactor contact erosion state recognition method based on multi-feature map

Abstract

The present application relates to the technical field of electrical equipment state monitoring, and particularly relates to a high-voltage direct-current contactor contact erosion state recognition method based on a multi-feature map. The method comprises the following steps: controlling a high-voltage direct-current contactor to perform an opening operation, and synchronously collecting arc evolution data and contact operating state information during contact separation; calculating arc temperature according to the arc evolution data; generating contact erosion data using the arc temperature and the contact operating state information; recognizing each contact erosion feature using the contact erosion data; recognizing erosion correlation for each contact erosion feature, and establishing an erosion multi-feature map according to the erosion correlation; and calculating arc burning energy of an arc heat action point based on the erosion multi-feature map. The present application realizes intelligent recognition and grade evaluation of high-voltage direct-current contactor contact erosion state based on electrical equipment state monitoring technology, and improves contact life prediction and operation reliability.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment condition monitoring technology, and in particular to a method for identifying the erosion status of high-voltage DC contactor contacts based on multi-feature maps. Background Technology

[0002] During the contact breaking process of a high-voltage DC contactor, an electric arc is generated between the contacts. The high-temperature thermal effect of the arc causes the contact material to melt, evaporate, and migrate, resulting in contact erosion and loss. Existing methods for identifying contact erosion status still have shortcomings: on the one hand, they lack comprehensive analysis of multi-source information such as arc temperature, arc energy, and contact operating status, making it difficult to accurately reflect the contact erosion formation process; on the other hand, existing methods mostly rely on a single erosion parameter for status judgment, failing to consider the correlation between arc thermal effect, material melting and migration, and surface loss, resulting in insufficient accuracy in erosion status identification and making it difficult to meet the long-term operating status monitoring requirements of high-voltage DC contactors. Summary of the Invention

[0003] Therefore, it is necessary for the present invention to provide a method for identifying the erosion status of high voltage DC contactor contacts based on multi-feature maps, in order to solve at least one of the above-mentioned technical problems.

[0004] To achieve the above objectives, a method for identifying the erosion status of high-voltage DC contactor contacts based on multi-feature maps includes the following steps: Step S1: Control the high-voltage DC contactor to perform the opening operation, and simultaneously collect arc evolution data and contact operating status information during the contact separation process; calculate the arc temperature based on the arc evolution data; and generate contact erosion data using the arc temperature and contact operating status information. Step S2: Identify the erosion characteristics of each contact using contact erosion data; identify the erosion correlation for each contact erosion characteristic, and establish a multi-feature erosion map based on the erosion correlation; Step S3: Calculate the arc energy at the arc thermal point based on the erosion multi-feature map; assess the contact erosion loss intensity based on the arc energy; classify the erosion multi-feature map according to the contact erosion loss intensity to obtain the contact erosion level; Step S4: Map the contact erosion level to the contact erosion node in the erosion multi-feature map, and output the contact erosion status identification result.

[0005] The beneficial effects of this invention are as follows: 1. By simultaneously collecting arc evolution data and contact operating status information during contact separation, and analyzing parameters such as arc temperature in the near-anode region, arc temperature in the near-cathode region, contact breaking speed, and contact displacement change, erosion data that includes arc thermal effects and contact operating status is generated. This solves the problem that existing technologies rely solely on single parameters such as current and arcing time to judge contact wear status, lacking comprehensive analysis of the arc process and contact heating differences, resulting in inaccurate characterization of contact erosion status. This improves the comprehensiveness and accuracy of contact erosion data acquisition.

[0006] 2. By utilizing contact erosion data to identify erosion characteristics such as arc temperature, arc energy, molten pool range, material migration, and material loss, and analyzing the correlation between these erosion characteristics, a multi-feature erosion map is established. This addresses the problem in existing technologies where different erosion factors are analyzed independently, making it difficult to describe the correlation and evolution between arc thermal effects, material melting and migration, and contact loss. It enables a multi-dimensional correlation expression of the contact erosion process and improves the ability to analyze contact erosion states.

[0007] 3. By calculating the arc energy at the point of thermal action of the electric arc based on the multi-feature erosion spectrum, and determining the material loss degree on the contact surface according to the changes in the contact temperature field, the melting state of the material, and the migration of the molten material under the action of the arc energy, the erosion loss intensity of the contact can be evaluated. This solves the problem that the existing technology only judges the degree of erosion by contact mass loss or surface morphology changes, which cannot reflect the dynamic loss process of the material under the action of the arc energy, and improves the accuracy of the assessment of the erosion loss intensity of the contact. Attached Figure Description

[0008] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the steps in the method for identifying the erosion state of high-voltage DC contactor contacts based on multi-feature maps according to the present invention. Figure 2 This is a schematic diagram of the erosion morphology of a high-voltage DC contactor contactor according to an embodiment. Figure 3 This is a schematic diagram of an erosion multi-feature map according to one embodiment; The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0009] The technical method of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0010] Furthermore, the accompanying drawings are merely illustrative of the invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor methods and / or microcontroller methods.

[0011] It should be understood that although the terms "first," "second," etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are used merely to distinguish one unit from another. For example, without departing from the scope of the exemplary embodiments, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0012] To achieve the above objectives, please refer to Figures 1 to 3 This invention provides a method for identifying the erosion state of high-voltage DC contactor contacts based on multi-feature maps. The method includes the following steps: Step S1: Control the high-voltage DC contactor to perform the opening operation, and simultaneously collect arc evolution data and contact operating status information during the contact separation process; calculate the arc temperature based on the arc evolution data; and generate contact erosion data using the arc temperature and contact operating status information. In one embodiment, a breaking control command is sent to the high-voltage DC contactor, causing the moving contact and stationary contact to separate at a preset breaking speed. After an arc forms in the contact gap, a high-speed camera captures images of the arc morphology changes, and simultaneously acquires voltage, current, and contact displacement data at both ends of the contact. The acquired arc evolution data is processed, and the arc thermal distribution state is determined based on the light radiation variation characteristics of the arc column region. The arc temperature is calculated in conjunction with the heat flow transfer process on the contact surface. The anode thermal effect area is determined based on the interface between the arc column and the anode contact, and the cathode thermal effect area is determined based on the cathode arc effect area. The arc temperature near the anode and near the cathode areas are calculated separately, and the two are fused to obtain the arc temperature change data during the breaking process. Based on the arc temperature, contact breaking speed, and contact displacement change, the thermal effect state and contact motion state corresponding to different time points are determined, generating contact erosion data containing arc thermal effect information and mechanical motion information.

[0013] In another embodiment, assuming the rated operating voltage of the high-voltage DC contactor is 450V and the breaking current is 300A, a high-speed camera is used to acquire arc evolution images at 10,000 frames / s, and contact operating status information is simultaneously acquired at 1kHz. During one breaking process, the contact separation time is 12ms, the maximum contact breaking speed is 1.8m / s, and the maximum contact displacement change is 5.5mm. Arc image analysis reveals a peak arc temperature of 6200K near the anode and 5800K near the cathode. Fusion calculations determine the arc temperature range for this breaking process to be 4500K~6200K, and contact erosion data including temperature change, breaking speed, and displacement change is generated.

[0014] Step S2: Identify the erosion characteristics of each contact using contact erosion data; identify the erosion correlation for each contact erosion characteristic, and establish a multi-feature erosion map based on the erosion correlation; In one embodiment, feature analysis is performed on the contact erosion data to extract arc thermal characteristics, contact material loss characteristics, and contact motion influence characteristics. Arc thermal characteristics include arc temperature variation trends, duration of thermal action, and heat accumulation areas; contact material loss characteristics include the molten area range, material migration direction, and surface loss degree; contact motion influence characteristics include contact breaking velocity, contact gap change, and arc movement trajectory. The relationships between these erosion characteristics are analyzed to determine the thermal correlation between arc temperature and material melting degree, the positional correlation between contact motion state and arc action area, and the evolutionary correlation between material migration characteristics and surface loss degree. Based on each erosion characteristic as a node and the erosion correlations as node connecting edges, a multi-feature erosion map is constructed.

[0015] In another embodiment, assuming contact erosion data is obtained from 20 high-voltage DC contactor breaking experiments, 50 arc temperature feature nodes, 40 thermal effect region feature nodes, 35 material melting feature nodes, 30 material migration feature nodes, and 25 wear degree feature nodes are extracted, totaling 180 erosion feature nodes. By analyzing the correlation between nodes, 65 correlation edges are identified between arc temperature nodes and melting region nodes, 48 ​​correlation edges between melting region nodes and material migration nodes, and 42 correlation edges between material migration nodes and wear degree nodes, forming an erosion multi-feature map containing 180 nodes and 155 correlation edges.

[0016] Of particular importance is that step S2 involves identifying erosion correlations for each contact erosion characteristic and establishing a multi-feature erosion map based on these correlations, including: For each contact erosion feature, determine the corresponding feature attribute information; calculate the correlation strength between any two contact erosion features based on the feature attribute information; select feature pairs that meet the correlation conditions based on the correlation strength to form erosion correlation relationships; In one embodiment, it is assumed that five types of erosion features generated during the contact erosion process are acquired, including arc thermal effect feature A, contact temperature rise feature T, molten pool range feature M, material migration feature L, and surface indentation feature D. The attribute information corresponding to each erosion feature is acquired, where the variation amplitude of arc thermal effect feature A is 85%, the variation amplitude of temperature rise feature T is 72%, the variation amplitude of molten pool range feature M is 60%, the variation amplitude of material migration feature L is 45%, and the variation amplitude of surface indentation feature D is 30%. The correlation strength is calculated based on the degree of synchronization between the changes of each feature, resulting in a correlation strength of 0.91 for AT, 0.86 for TM, 0.82 for ML, 0.78 for LD, 0.35 for AD, and 0.42 for TD. Setting the correlation condition to a correlation strength greater than 0.70, four feature pairs (AT, TM, ML, and LD) are selected, forming corresponding erosion correlation relationships. These erosion correlation relationships can reflect the continuous erosion evolution process of the contact from arc thermal input, temperature rise, material melting to material loss.

[0017] The erosion characteristics of each contact are used as nodes in the graph, and the erosion relationships are used as edges in the graph. An erosion multi-feature graph is constructed based on the graph nodes and graph edges.

[0018] In one embodiment, the erosion features of each contact are mapped to graph nodes in a multi-feature erosion map, and the erosion relationships between different erosion features are mapped to graph edges. Graph nodes are used to represent different state features of the contact during the erosion process, and graph edges are used to represent the correlation and transmission relationships between different state features. Node attribute parameters are configured according to the feature attribute information corresponding to each graph node, and graph edge weights are configured according to the correlation strength corresponding to the erosion correlation, so as to establish a multi-feature erosion map containing erosion state information and feature correlation information.

[0019] Step S3: Calculate the arc energy at the arc thermal point based on the erosion multi-feature map; assess the contact erosion loss intensity based on the arc energy; classify the erosion multi-feature map according to the contact erosion loss intensity to obtain the contact erosion level; In one embodiment, assuming a certain type of high-voltage DC contactor performs 50 consecutive switching operations, the arc energy during each switching process is calculated using a multi-feature erosion profile to be 15J, 22J, 35J, 48J, and 65J, respectively. Based on the arc energy conversion, the highest contact surface temperatures are 850℃, 980℃, 1250℃, 1450℃, and 1700℃, respectively. When the temperature exceeds 1200℃, the contact material is considered to have entered a significantly molten state. The calculated material loss rates on the contact surface are 0.05%, 0.12%, 0.35%, 0.75%, and 1.2%, respectively. Based on the loss rate range, the erosion state is classified into three levels: Level 1 (slight erosion), Level 2 (moderate erosion), and Level 3 (severe erosion).

[0020] Step S4: Map the contact erosion level to the contact erosion node in the erosion multi-feature map, and output the contact erosion status identification result.

[0021] In one embodiment, a corresponding erosion level label is generated based on the contact erosion level, and the contact erosion node corresponding to the current contact state is determined in the erosion multi-feature map. The erosion level label is associated with the contact erosion node, the erosion level information is written into the corresponding node attribute, and the association state between the contact erosion node and other erosion feature nodes is updated. Based on the updated erosion multi-feature map, the current erosion level, erosion area, and loss trend information of the contact are read to generate a contact erosion state identification result.

[0022] In another embodiment, it is assumed that the erosion multi-feature map contains 100 contact erosion nodes, where nodes T01~T40 correspond to Level 1 erosion, nodes T41~T75 correspond to Level 2 erosion, and nodes T76~T100 correspond to Level 3 erosion. When the target contact corresponding to node T82 is detected, the Level 3 erosion label is written to node T82, and the material loss of this node is updated to 1.2%, the cumulative arc energy is 65J, and the number of thermal effects is 50, outputting the identification result "Level 3 erosion state, high thermal effect accumulation exists, contact maintenance is recommended".

[0023] Preferably, in step S1, controlling the high-voltage DC contactor to perform an opening operation, and simultaneously acquiring arc evolution data and contact operating status information during contact separation, includes: Receive the opening control command of the high voltage DC contactor, control the moving contact and stationary contact to perform separation action according to the opening control command, and collect the arc evolution data in the contact gap area during the contact separation process; In one embodiment, a control module receives the opening control command of a high-voltage DC contactor and outputs a separation control signal to the drive mechanism according to the opening control command, causing the moving contact to separate from the stationary contact along a preset movement direction. During the separation process of the moving and stationary contacts, a high-speed acquisition device continuously samples the contact gap area to acquire arc evolution data during arc formation, expansion, and attenuation. The high-speed acquisition device includes a high-speed camera and an arc detection sensor. The high-speed camera acquires images of arc morphology changes at different time points, and the arc detection sensor acquires information on arc brightness changes, arc length changes, and arc action area changes. The acquired arc evolution data is processed in a time-synchronized manner to establish an arc evolution sequence corresponding to the contact separation process, thus characterizing the dynamic changes of the arc thermal action area during contact opening.

[0024] In another embodiment, assuming the rated voltage of the high-voltage DC contactor is 450V and the rated current is 300A, upon receiving the interruption control command, the moving contact is controlled to perform a separation action, and a high-speed camera is used to acquire images of the contact gap area at a sampling frequency of 10,000 frames / s. During the acquisition process, the initial contact gap is 0.2mm, the arc first formation time is 0.8ms, the arc duration is 8ms, and the contact separation distance is 6mm. Simultaneously, the arc length change data is acquired through an arc detection sensor, wherein the arc length gradually expands from 0.5mm to 5.2mm, and the arc action area area increases from 0.8mm² to 12.5mm².

[0025] Calculate the contact breaking speed and contact displacement change during the contact separation process, and encapsulate the contact breaking speed and contact displacement change into contact operating status information.

[0026] In one embodiment, based on continuously collected contact position data during contact separation, the position coordinates of the moving contact at different sampling times are determined, and the contact displacement change is calculated based on the position difference between adjacent sampling times. According to the relationship between the contact displacement change and the corresponding time interval, the contact breaking speed is calculated to obtain the motion changes of the contact from the closed state to the fully separated state. Based on the trend of the contact breaking speed change and the contact displacement change, the contact operating state is parameterized and described, and the contact breaking speed data, contact displacement change data, and corresponding time markers are associated and encapsulated to form contact operating state information.

[0027] In another embodiment, assuming a displacement sensor is used to acquire the motion data of the moving contact at a sampling frequency of 1kHz, the contact position change is continuously collected at 10 time points during a single breaking process, resulting in contact displacement data of 0.2mm, 0.8mm, 1.6mm, 2.7mm, 3.9mm, 4.8mm, 5.6mm, 6.3mm, 6.8mm, and 7.0mm. Based on adjacent sampling time intervals, the corresponding contact breaking velocities are calculated to be 0.3m / s, 0.7m / s, 1.1m / s, 1.4m / s, 1.6m / s, 1.5m / s, 1.2m / s, 0.8m / s, and 0.4m / s. The contact breaking velocity, contact displacement change, and acquisition time information are encapsulated to generate contact operating status information, including a maximum breaking velocity of 1.6m / s, a maximum displacement change of 7.0mm, and a motion change curve of the complete separation process.

[0028] Preferably, the calculation of the arc temperature based on the arc evolution data in step S1 includes: The anode heat flux density at the junction of the arc column and the anode contact is collected based on the arc evolution data; the anode input energy is calculated using the anode heat flux density, and the anode thermal intensity is calculated; the arc temperature in the near-anode region is calculated based on the anode thermal intensity. In one embodiment, assuming that when the high-voltage DC contactor performs a single switching operation, the arc duration is 8 ms and the area of ​​the interface between the arc column and the anode contact is 4 mm², the anode heat flux density is obtained through arc evolution data analysis. , , , as well as Based on the changes in heat flux density, the anode input energy was calculated to be 2.5 J, 3.8 J, 5.2 J, 6.5 J, and 4.6 J, respectively, and the anode thermal intensity was determined to be 0.35, 0.52, 0.76, 0.91, and 0.68, respectively. Based on these thermal intensities, the arc temperature range near the anode was calculated to be 4800 K to 6200 K, with the highest temperature corresponding to the time point of maximum anode thermal intensity.

[0029] The cathode arc effect area of ​​the cathode contact is marked based on the arc evolution data; the electron emission state of the cathode arc effect area is obtained and the cathode thermal effect intensity is calculated; the arc temperature in the near-cathode region is calculated using the cathode thermal effect intensity. In one embodiment, the arc-affected region on the cathode contact surface is identified based on the arc spatial distribution information in the arc evolution data. The location range of the cathode arc-affected region is determined by analyzing changes in arc intensity, arc movement trajectory, and concentrated current areas on the cathode surface. Electron emission state information is acquired within the cathode arc-affected region, and the energy release in the cathode region is determined based on the number of electrons emitted from the cathode surface, electron migration velocity, and electron emission duration. The degree of cathode heat accumulation is calculated based on the energy input generated during electron emission, and the cathode thermal intensity is determined by combining this with the area of ​​the cathode arc-affected region. Based on the mapping relationship between cathode thermal intensity and arc temperature, the arc temperature near the cathode contact region is calculated, obtaining near-cathode arc temperature variation data.

[0030] In another embodiment, assuming that during a high-voltage DC contactor disconnection process, data on the change in the area of ​​the cathode arcing region is acquired via a high-speed camera, with the cathode arcing region areas being 2 mm², 3.5 mm², 5 mm², 6.2 mm², and 4.8 mm², respectively. The number of electron emissions at corresponding time points is obtained through electron emission detection. per second per second per second units / s and Electron emission rates per second (electrons) were calculated based on the electron emission states to be 1.5 J / ms, 2.2 J / ms, 3.1 J / ms, 3.8 J / ms, and 2.7 J / ms, respectively, and the cathode thermal intensities were determined to be 0.28, 0.45, 0.72, 0.86, and 0.61, respectively. The calculated near-cathode arc temperatures were 4300 K, 5000 K, 5700 K, 5900 K, and 5200 K, respectively.

[0031] The arc temperature during the breaking process is determined by using the arc temperature near the anode and the arc temperature near the cathode.

[0032] In one embodiment, after acquiring the arc temperature near the anode and near the cathode, the arc temperature change data of the two regions are time-synchronized and matched to establish a correspondence between the near-anode and near-cathode temperature data at the same breaking moment. Based on the thermal contributions of the anode and cathode regions during arc formation, the near-anode and near-cathode arc temperatures are fused and calculated to determine the overall arc temperature at different breaking moments. Using arc temperature data from continuous time points, an arc temperature change curve during contact separation is generated.

[0033] In another embodiment, assuming that during a single interruption process, the arc temperature sampling results near the anode region are 6200K, 5800K, 5400K, 5000K, and 4600K, and the arc temperature sampling results near the cathode region are 5900K, 5600K, 5200K, 4800K, and 4400K, respectively. Based on the thermal contribution ratio of 0.6:0.4 between the anode and cathode regions, temperature fusion is performed, and the corresponding arc temperatures at the interruption time are calculated to be 6080K, 5720K, 5320K, 4920K, and 4520K. Based on continuous sampling results, the arc temperature variation range during this interruption process is determined to be 4520K~6080K, with the highest arc temperature occurring during the rapid expansion phase of the contact gap.

[0034] Preferably, the calculation of the anode input energy and the anode thermal intensity using the anode heat flux density includes: The heat transfer rate from the arc column to the anode contact surface is determined using the anode heat flux density; the arc burning time is recorded, and the cumulative amount of heat received by the anode contact is calculated using the heat transfer rate. In one embodiment, after obtaining the anode heat flux density at the interface between the arc column and the anode contact, the heat transfer rate from the arc column to the anode contact surface per unit time is determined based on the correspondence between the anode heat flux density and the heat transfer area. Specifically, the effective area of ​​the arc column acting on the anode contact surface is determined based on arc evolution data, and the change in heat transfer rate within each time period is calculated by combining the changes in anode heat flux density at different time points. By recording the duration of the arc during contact separation, the corresponding arc ignition time is determined, and the heat transfer rate within each time period is integrated over time to obtain the cumulative heat of the anode contact during the entire arc ignition process, thus characterizing the continuous heat input effect of the arc on the anode contact.

[0035] In another embodiment, assuming that the arc ignition time is 10ms when the high-voltage DC contactor performs a single interruption operation, and the anode heat flux density change data are acquired during the arc ignition process, respectively... , , , as well as The corresponding arc areas are respectively , , , as well as The heat transfer rates from the arc column to the anode contact surface were calculated to be 2W, 4.8W, 8.8W, 14W, and 7.2W based on the heat flux density and the effective area. The cumulative heat received by the anode contact was calculated to be 0.02J, 0.048J, 0.088J, 0.14J, and 0.072J based on the arcing time, thus determining the cumulative anode heat input state during this interruption process.

[0036] The anode input energy is calculated based on the cumulative amount of heat received by the anode contact; the thermal effect of the anode input energy on the anode contact surface is evaluated to form a heat distribution result; and the anode thermal intensity is calculated based on the heat distribution result.

[0037] In one embodiment, the heat input process at different time stages is accumulated based on the cumulative heat received by the anode contact to obtain the total input energy received by the anode contact during the arcing process. The anode input energy is mapped onto the anode contact surface, and the thermal effect distribution results on the anode contact surface are established based on the heat diffusion range, accumulation area, and distribution gradient on the contact surface. Specifically, the heat density in different regions of the anode contact surface is analyzed to determine the concentrated area of ​​arc thermal effect and the range of thermal influence. The thermal effect intensity corresponding to different regions is calculated based on the heat distribution results, and the thermal effect intensity is correlated with the corresponding spatial location to obtain the anode thermal effect intensity distribution data.

[0038] In another embodiment, assuming the accumulated heat received by the anode contact during a single interruption is calculated to be 0.45 J, and the anode input energy is determined to be 0.52 J based on the heat input during the arcing process, this input energy is mapped onto the anode contact surface, resulting in 25 thermal effect analysis regions. Regions A01-A05 are located at the arc concentration point, regions A06-A15 are located in the heat diffusion region, and regions A16-A25 are located in the low heat influence region. After thermal effect evaluation, the heat distribution values ​​for each region are 0.12 J, 0.10 J, 0.08 J, 0.06 J, and 0.04 J, respectively. Based on the heat distribution gradient, the corresponding thermal effects intensity for each region is calculated to be 0.85, 0.72, 0.56, 0.38, and 0.21, respectively, with the region of maximum thermal effect intensity corresponding to the interface between the arc column and the anode contact.

[0039] Preferably, obtaining the electron emission state of the cathode arc region and calculating the cathode thermal intensity includes: Obtain the electron emission state of the cathode arc region and calculate the number of electrons emitted; determine the energy release rate of the cathode region using the number of electrons emitted; calculate the cathode heat input value based on the energy release rate of the cathode region. In one embodiment, after determining the cathode arcing area on the cathode contact surface, the electron emission state within that area is collected and analyzed. By acquiring changes in cathode surface current density, arc brightness, and cathode spot movement, the variation process of electron emission behavior within the cathode area is determined. Based on the electron emission area, electron emission duration, and the number of electrons migrating per unit time, the number of electrons emitted from the cathode arcing area is calculated. Based on the energy conversion relationship between the number of electrons emitted and the electron migration process, the energy release rate corresponding to the cathode area is determined, and the heat input value of the cathode area during the arcing process is calculated in conjunction with the electron emission duration to characterize the impact of electron emission behavior on the heat input of the cathode contact surface.

[0040] In another embodiment, assuming that during a high-voltage DC contactor disconnection process, the areas of the cathode arcing region obtained by the electron emission detection device are 1.5 mm², 2.5 mm², 3.8 mm², 4.5 mm², and 3.2 mm², respectively, and the corresponding number of electron emissions collected are respectively... per second per second per second units / s and The electron emission rate was calculated to be 1.2 J / ms, 1.8 J / ms, 2.6 J / ms, 3.4 J / ms, and 2.1 J / ms, respectively. With an arc duration of 8 ms, the calculated cathode heat input values ​​were 0.096 J, 0.144 J, 0.208 J, 0.272 J, and 0.168 J, respectively, with the maximum heat input value corresponding to the moment of highest electron emission.

[0041] The degree of heat accumulation in the cathode region is calculated using the cathode heat input value; the intensity of cathode thermal effect is determined based on the degree of heat accumulation in the cathode region.

[0042] In one embodiment, after obtaining the heat input value of the cathode region, the heat accumulation state at different locations is analyzed based on the spatial distribution of the heat input value within the cathode arc action area. The cathode heat input value is mapped onto the cathode contact surface to determine the heat density corresponding to each region, and the degree of heat accumulation in the cathode region is calculated based on the heat density change gradient. Specifically, regions with high heat input per unit area and long duration are identified as heat concentration regions; regions with a large heat diffusion range and low input intensity are identified as heat dispersion regions. Based on the degree of heat accumulation and the thermal action range of the cathode region, the cathode thermal action intensity is calculated, and a correspondence between the cathode arc action area and the thermal action intensity is established.

[0043] In another embodiment, assuming the cathode arc effect area is divided into 20 thermal effect analysis units, the heat densities of each unit are calculated to be 0.05 J / mm², 0.08 J / mm², 0.12 J / mm², 0.18 J / mm², and 0.25 J / mm², respectively, based on the cathode heat input value. Regions A01-A05 are located in the concentrated cathode arc effect area, regions A06-A15 are located in the heat diffusion area, and regions A16-A20 are located in the low heat influence area. Based on the heat density distribution and heat duration of each region, the heat accumulation degree is calculated to be 0.22, 0.38, 0.55, 0.76, and 0.92, respectively. The corresponding cathode thermal effect intensities are determined to be 0.18, 0.32, 0.51, 0.73, and 0.88, with the region of highest thermal effect intensity corresponding to the concentrated cathode electron emission area.

[0044] Preferably, step S3, which assesses the contact erosion loss intensity based on the arc energy, includes: The arc energy is converted into a contact temperature field. When the temperature of the contact temperature field is greater than the preset melting point threshold, the contact material is determined to be in a melting state. The degree of melting is assessed based on the melting state of the contact material. The range of the molten pool on the contact surface is marked based on the degree of melting. The migration direction of the molten material within the molten pool range on the contact surface is identified. In one embodiment, the heat generated during the arcing process is mapped onto the contact surface based on the arc energy calculated from the multi-feature erosion map, establishing a temperature field distribution model for the contact surface. Specifically, the temperature changes at different spatial locations of the contact are determined based on the location and duration of the arc energy's action and the thermal conductivity of the contact material. The temperature values ​​of each region in the contact temperature field are compared with a preset melting point threshold. When the temperature of a certain region exceeds the melting point threshold of the contact material, that region is identified as the contact material melting region. The degree of contact material melting is calculated based on the temperature range and duration exceeding the melting point threshold, and the molten area on the contact surface is divided according to the degree of melting in different regions, determining the range of the molten pool on the contact surface. After determining the range of the molten pool, the migration direction of the molten material on the contact surface is identified based on the temperature gradient change within the molten pool, the material flow state, and the direction of the arc.

[0045] In another embodiment, assuming a certain type of high-voltage DC contactor uses a silver-based contact material with a melting point threshold of 1234℃, the temperature field distribution on the contact surface is calculated based on the arc energy, with different regions having temperatures of 850℃, 1050℃, 1280℃, 1450℃, and 1620℃. Comparing the temperature field with the melting point threshold, regions at 1280℃, 1450℃, and 1620℃ are determined to have entered the material melting state. Based on the temperature difference exceeding the melting point threshold in each region, the degree of melting is calculated to be 0.15, 0.42, 0.68, and 0.85, respectively, and molten pool regions with areas of 0.8mm², 1.5mm², 2.8mm², and 4.2mm² are determined. Analysis based on the direction of the internal temperature gradient of the molten pool and the direction of the arc action indicates that the molten material mainly migrates radially outward along the contact, with a maximum migration direction offset angle of 35°.

[0046] The amount of molten material is calculated along the migration direction of the molten material, and the amount of molten material is used to calculate the material loss degree on the contact surface; the contact erosion loss intensity is evaluated based on the material loss degree on the contact surface.

[0047] In one embodiment, after determining the migration direction of the molten material on the contact surface, the volume of molten material moving along the migration direction is calculated based on the length and width of the molten region and the material migration distance. Specifically, a molten material migration distribution is established based on the amount of material migration at different locations within the molten pool, and the total molten amount in each region is accumulated to obtain the total molten amount on the contact surface. The material loss degree on the contact surface is calculated based on the relationship between the initial material volume of the contact, the effective contact area, and the amount of molten material loss. Based on the range of material loss degree variation, the degree of contact erosion is divided into different loss levels, and the intensity of contact erosion loss is evaluated by combining the thermal characteristics, material migration characteristics, and loss characteristics in the multi-feature erosion profile.

[0048] In another embodiment, assuming that during a single continuous interruption process, the migration lengths of the molten material in the contact are 0.5 mm, 1.2 mm, 1.8 mm, and 2.5 mm, respectively, obtained through analysis of the molten pool region, corresponding to molten region volumes of 0.02 mm³, 0.06 mm³, 0.12 mm³, and 0.20 mm³, respectively. Based on the migration direction of the molten material, the melting amounts during a single interruption process are calculated to be 0.018 mm³, 0.055 mm³, 0.115 mm³, and 0.190 mm³, respectively, with a cumulative melting amount of 0.378 mm³. Assuming the initial effective material volume of the contact is 50 mm³, the calculated material loss rates on the contact surface are 0.036%, 0.11%, 0.23%, and 0.38%, respectively. Based on the range of material loss rates, the contact erosion intensity is divided into three levels: Level 1 slight loss, Level 2 moderate loss, and Level 3 severe loss. A material loss rate exceeding 0.3% corresponds to Level 3 erosion loss, and the corresponding contact erosion intensity assessment results are output.

[0049] Most importantly, the arc energy is converted into a contact temperature field. When the temperature of the contact temperature field exceeds a preset melting point threshold, the contact material is determined to be in a melting state, including: The energy of the burning arc is converted into the heat input intensity of the electric arc, and the heat input intensity of the electric arc is used to determine the thermal boundary conditions; the heat transfer of the contact is simulated based on the thermal boundary conditions to form temperature distribution data; In one embodiment, arc energy data generated during the opening and closing operation of a high-voltage DC contactor is acquired. This arc energy data includes arc voltage, arc current, and arc duration. Based on the change in arc energy over time, the arc energy is converted into arc heat input intensity, which characterizes the heat transfer capacity of the arc to the contact surface per unit time. The thermal boundary conditions corresponding to the contact heat transfer process are determined based on the arc heat input intensity. These thermal boundary conditions include the location of the heat input region, heat flux density distribution, and the duration of the heat effect. The thermal boundary conditions are then loaded into a three-dimensional heat transfer model of the contact. Based on the thermal properties of the contact material, such as thermal conductivity, specific heat capacity, and density, the heat transfer process during the arc is simulated, and the temperature changes at different spatial locations of the contact are calculated to form contact temperature distribution data.

[0050] In another embodiment, assuming the arc voltage is 120V, the arc current is 80A, and the arc duration is 15ms during a single interruption of the high-voltage DC contactor, the calculated arc energy is approximately 144J. Based on the distribution of arc energy over time, the arc heat input intensity is divided into an initial enhancement stage, a stable action stage, and a decay stage, with the maximum heat input intensity reaching 9.6kW. A circular region with a diameter of 5mm on the contact surface is determined as the heat input region based on the arc action area, and the heat flux density in the thermal boundary conditions is set to 1.2×10^6W / m², with a thermal action time of 15ms. After inputting the above thermal boundary conditions into the contact heat transfer model, the temperature rise rate in the central region of the contact surface is the fastest, while the temperature change in the edge region is relatively slow, forming temperature distribution data containing temperature values ​​at different locations on the contact surface and inside.

[0051] A contact temperature field is constructed based on temperature distribution data. When the temperature of the contact temperature field is greater than the preset melting point threshold, it is determined that the contact material is in a melting state.

[0052] In one embodiment, based on temperature distribution data, the contact space is divided according to a preset grid size, and the temperature data corresponding to each grid node is spatially mapped to construct a three-dimensional temperature field for the contact. This temperature field characterizes the temperature changes in different regions of the contact during the arcing process. The melting point threshold corresponding to the contact material is obtained, and the temperature values ​​at each location in the temperature field are compared with the melting point threshold. When the temperature value of a certain region is greater than or equal to the melting point threshold, that region is marked as a material melting region, and the contact is determined to be in a material melting state; when the temperature value is lower than the melting point threshold, the corresponding region is determined to remain in a solid state. By continuously analyzing the temperature field at different time points, the spatial expansion range of the contact material during its transition from solid to liquid can be obtained.

[0053] In another embodiment, assuming the contact material is a silver alloy with a melting point threshold of 960°C, a contact temperature field is constructed based on temperature distribution data, and the highest temperatures at different time points within a 15ms arc duration are: 820°C at 5ms, 980°C at 10ms, and 1120°C at 15ms. At 10ms, a region with an area of ​​approximately 2mm² in the temperature field has a temperature exceeding 960°C; this region is then identified as the initial melting region. At 15ms, the region exceeding the melting point threshold expands to 6mm², indicating the formation of a continuous melting region on the contact surface. Simultaneously, assuming the contact surface is divided into 100 temperature grid cells, with 8 grid cells exceeding the melting point threshold at 10ms and 24 grid cells exceeding the melting point threshold at 15ms, the evolution of the contact material's melting state is determined based on the changes in the melting region at different time points.

[0054] Preferably, the range of the molten pool on the contact surface is marked according to the degree of melting, including: Calculate the melting temperature based on the degree of melting, and determine the phase transformation state of the material based on the melting temperature; calculate the proportion of the contact material that changes from solid to liquid based on the phase transformation state of the material, and mark the position of the solid-liquid interface on the contact surface; In one embodiment, assuming the high-voltage DC contactor uses silver-tin oxide contact material with a contact melting point of 1080°C, the solid-liquid phase transition temperature range is set to 1050°C–1100°C. Melting degree data for different regions of the contact surface are collected, and the melting temperatures corresponding to the five detection regions are calculated to be 980°C, 1065°C, 1090°C, 1125°C, and 1150°C. The 980°C region is identified as a solid region; the 1065°C and 1090°C regions are identified as solid-liquid coexistence regions; and the 1125°C and 1150°C regions are identified as liquid regions. The calculated liquid transition ratios for each region are 0%, 35%, 65%, 90%, and 100%, respectively. Regions with a liquid transition ratio greater than 50% are identified as melt expansion regions, and the solid-liquid phase interface is marked between the second and third detection regions. The change in the position of the solid-liquid phase interface reflects the melting and diffusion process of the contact material after being subjected to arc heat.

[0055] The contact surface melting zone is divided according to the location of the solid-liquid phase interface on the contact surface, and the range of the molten pool on the contact surface of the melting zone is calculated.

[0056] In one embodiment, the contact surface is divided into regions based on the location of the solid-liquid interface. The liquid region within the solid-liquid interface is defined as the molten region of the contact surface, and the spatial coordinates of each point within the molten region are obtained. Then, based on the spatial connectivity between these points, the boundaries of the continuously distributed molten regions are determined, and the projection range of the molten regions onto the contact surface is calculated. Based on the coordinates of the boundary points of the molten regions, the length, width, and coverage area of ​​the molten regions are calculated, forming the molten pool range of the contact surface.

[0057] In another embodiment, it is assumed that three continuous molten regions exist on the contact surface through solid-liquid interface detection. The first molten region contains 120 surface sampling points, the second molten region contains 80 surface sampling points, and the third molten region contains 45 surface sampling points. The boundary range of each molten region is calculated based on the three-dimensional coordinates of each sampling point. The first molten region has a length of 2.5 mm, a width of 1.8 mm, and a coverage area of ​​4.5 mm²; the second molten region has a length of 1.6 mm, a width of 1.2 mm, and a coverage area of ​​2.1 mm²; and the third molten region has a length of 0.9 mm, a width of 0.7 mm, and a coverage area of ​​0.6 mm². The three molten regions are merged, resulting in a total molten pool area of ​​7.2 mm² on the contact surface, with the first molten region being the main area of ​​concentrated thermal erosion. By calculating the molten pool range on the contact surface, the influence of arc heating on the migration and erosion propagation of the contact material can be determined.

[0058] Preferably, in step S3, the erosion multi-feature spectrum is classified into levels based on the contact erosion loss intensity to obtain the contact erosion levels, including: The loss weight of each erosion feature node in the erosion multi-feature spectrum is determined based on the contact erosion loss intensity; the loss correlation between each erosion feature node is analyzed based on the loss weight to determine the erosion state correlation region. In one embodiment, the weights of each erosion feature node in the erosion multi-feature map are calculated based on the contact erosion loss intensity. Erosion parameters corresponding to each erosion feature node in the erosion multi-feature map are obtained, including arc energy, thermal intensity, material loss, molten pool area, and contact surface morphology changes. Based on the influence between the erosion parameters corresponding to each erosion feature node and the contact erosion loss intensity, the loss contribution value of each erosion feature node is calculated and normalized to obtain the loss weight corresponding to each erosion feature node. Based on the connection relationships between each erosion feature node and the changes in loss weights, the loss correlation degree between adjacent erosion feature nodes is calculated. When the loss correlation degree between two erosion feature nodes is greater than a preset correlation threshold, the two erosion feature nodes are determined to be correlated nodes, and multiple correlated erosion feature nodes are combined to form an erosion state correlation region.

[0059] The erosion multi-feature map is divided into graph structures based on the associated regions of erosion state, forming erosion feature sub-maps corresponding to different erosion states; the contact erosion level is determined based on the erosion feature sub-maps.

[0060] In one embodiment, it is assumed that after dividing the multi-feature map of erosion according to the erosion state association region, three erosion feature sub-maps are formed, namely the first erosion feature sub-map G1, the second erosion feature sub-map G2, and the third erosion feature sub-map G3. The first erosion feature sub-map G1 includes arc thermal effect nodes, molten pool expansion nodes, and material migration nodes, totaling 5 erosion feature nodes, with a cumulative node loss weight of 0.42 and an association strength of 0.78. The second erosion feature sub-map G2 includes cathodic erosion nodes, anodic erosion nodes, and surface pit nodes, totaling 6 erosion feature nodes, with a cumulative node loss weight of 0.68 and an association strength of 0.86. The third erosion feature sub-map G3 includes crack propagation nodes and mass loss nodes, totaling 4 erosion feature nodes, with a cumulative node loss weight of 0.91 and an association strength of 0.93. Based on the erosion state characterization values ​​corresponding to each erosion feature sub-map, a level matching is performed to determine that G1 corresponds to a slight erosion level, G2 corresponds to a moderate erosion level, and G3 corresponds to a severe erosion level. The overall erosion level of the current contact is determined based on the highest erosion level of each erosion feature sub-map, and the contact erosion status assessment result is output.

[0061] Preferably, the erosion multi-feature map is divided into graph structures based on the associated regions of erosion states, forming erosion feature sub-maps corresponding to different erosion states, including: Extract the set of associated nodes from the erosion multi-feature map based on the associated regions of the erosion state; extract the corresponding erosion node associated edges based on the set of associated nodes; In one embodiment, based on the determined erosion state association region, feature nodes related to the contact erosion state change are located in the erosion multi-feature map. These erosion feature nodes include contact surface temperature nodes, material loss nodes, melting zone nodes, arc action nodes, and surface morphology change nodes. Based on the spatial position and state change relationships of each erosion feature node within the erosion state association region, nodes associated with the current erosion state are selected to form an erosion node set. The association relationship between any two nodes in the erosion node set is obtained, and the node association edges are determined based on the state transmission direction, degree of change synchronization, and erosion influence path between nodes, resulting in the corresponding erosion node association edge set.

[0062] In another embodiment, it is assumed that the erosion state association region includes five erosion feature nodes: temperature feature node T1, molten pool range node M1, material loss node L1, surface depression node D1, and arc action node A1. Based on the erosion state change relationships between nodes, the associated node set {T1, M1, L1, D1, A1} is extracted. Analyzing the association paths between nodes, it is determined that there is an arc heat input association edge between T1 and A1, a melt formation association edge between A1 and M1, a material migration association edge between M1 and L1, and a surface loss association edge between L1 and D1, resulting in a total of four erosion node association edges. Through the above associated node set and association edges, a local feature association network corresponding to the contact erosion process can be formed.

[0063] The connection strength is calculated based on the associated edges of the erosion nodes. The connection strength is then used to aggregate and divide the erosion multi-feature map, forming erosion feature sub-maps corresponding to different erosion states.

[0064] In one embodiment, it is assumed that the erosion multi-feature map contains eight erosion feature nodes, including an arc-induced node A1, a temperature-increase node T1, a molten pool formation node M1, a material migration node L1, a surface depression node D1, and other auxiliary feature nodes. The calculated connection strengths of the associated edges are: A1-T1 = 0.92, T1-M1 = 0.86, M1-L1 = 0.81, L1-D1 = 0.76, A1-D1 = 0.35, and T1-D1 = 0.28. Setting the connection strength threshold to 0.70, the associated edges between A1, T1, M1, L1, and D1 are retained and aggregated to form the first erosion feature sub-map; the associated edges between A1-D1 and T1-D1 are disconnected, preventing the related nodes from participating in the aggregation of this erosion state sub-map. Suppose that in another set of contact operation data, the number of nodes in the molten pool range increases to 6, and the strength corresponding to the material loss nodes increases to 0.88. Then, the erosion feature sub-map formed by polymerization changes from a sub-map of slight thermal effects to a sub-map of enhanced material migration. By using the structural differences of different erosion feature sub-maps, the state classification of different erosion stages of the contact can be achieved.

[0065] It should be noted that you should refer to [link / reference]. Figure 2 The image shows the surface damage characteristics of the contact after being subjected to an electric arc, including the oxidation and discoloration area, the raised area formed by material migration, the ablation pit, the corresponding depression area, and the edge chipping (erosion) area. The right side shows magnified ablation pit features, molten solidified layer, material migration features, and edge erosion notches, which are used to characterize the thermal effects, material melting, migration, and wear evolution process of the contact during the arcing process.

[0066] It should be noted that you should refer to [link / reference]. Figure 3The graph uses nodes and edges to represent the relationships between different erosion features. Here, A represents the arc heating feature, T represents the contact temperature rise feature, M represents the molten pool extent feature, L represents the material migration feature, and D represents the surface depression feature. Solid arrows indicate high-intensity erosion correlations that meet the correlation conditions, while dashed lines indicate low-intensity correlations. The graph illustrates the erosion evolution path between arc heating, temperature rise, molten pool expansion, material migration, and surface depression, and the correlation strength numerical values ​​characterize the degree of influence between different erosion features, thus constructing a multi-feature correlation model for contact erosion state analysis.

[0067] Therefore, the embodiments should be considered as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the application are intended to be included within the invention.

[0068] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A method for identifying the erosion state of high-voltage DC contactor contacts based on multi-feature maps, characterized in that, Includes the following steps: Step S1: Control the high-voltage DC contactor to perform the opening operation, and simultaneously collect arc evolution data and contact operating status information during the contact separation process; calculate the arc temperature based on the arc evolution data; and generate contact erosion data using the arc temperature and contact operating status information. Step S2: Identify the erosion characteristics of each contact using contact erosion data; identify the erosion correlation for each contact erosion characteristic, and establish a multi-feature erosion map based on the erosion correlation; Step S3: Calculate the arc energy at the arc thermal point based on the multi-feature erosion map; assess the contact erosion loss intensity based on the arc energy; The erosion multi-feature map is classified according to the contact erosion loss intensity to obtain the contact erosion level. This includes: determining the loss weight of each erosion feature node in the erosion multi-feature map based on the contact erosion loss intensity; and analyzing the loss correlation between each erosion feature node based on the loss weight to determine the erosion state correlation region. The erosion multi-feature map is divided into graph structures based on the associated regions of erosion states, forming erosion feature sub-maps corresponding to different erosion states, including: Extract the set of associated nodes from the erosion multi-feature map based on the associated regions of the erosion state; extract the corresponding erosion node associated edges based on the set of associated nodes; The connection strength is calculated based on the associated edges of the erosion nodes. The connection strength is then used to aggregate and divide the erosion multi-feature map to form erosion feature sub-maps corresponding to different erosion states. The contact erosion level is then determined based on the erosion feature sub-maps. Step S4: Map the contact erosion level to the contact erosion node in the erosion multi-feature map, and output the contact erosion status identification result.

2. The method for identifying the erosion state of high-voltage DC contactor contacts based on multi-feature maps according to claim 1, characterized in that, In step S1, the high-voltage DC contactor is controlled to perform an opening operation. During the contact separation process, arc evolution data and contact operating status information are collected simultaneously, including: Receive the opening control command of the high voltage DC contactor, control the moving contact and stationary contact to perform separation action according to the opening control command, and collect the arc evolution data in the contact gap area during the contact separation process; Calculate the contact breaking speed and contact displacement change during the contact separation process, and encapsulate the contact breaking speed and contact displacement change into contact operating status information.

3. The method for identifying the erosion state of high-voltage DC contactor contacts based on multi-feature maps according to claim 1, characterized in that, Step S1, which calculates the arc temperature based on the arc evolution data, includes: The anode heat flux density at the junction of the arc column and the anode contact is collected based on the arc evolution data; the anode input energy is calculated using the anode heat flux density, and the anode thermal intensity is calculated; the arc temperature in the near-anode region is calculated based on the anode thermal intensity. The cathode arc effect area of ​​the cathode contact is marked based on the arc evolution data; the electron emission state of the cathode arc effect area is obtained and the cathode thermal effect intensity is calculated; the arc temperature in the near-cathode region is calculated using the cathode thermal effect intensity. The arc temperature during the breaking process is determined by using the arc temperature near the anode and the arc temperature near the cathode.

4. The method for identifying the erosion state of high-voltage DC contactor contacts based on multi-feature maps according to claim 3, characterized in that, The calculation of anode input energy and anode thermal intensity using anode heat flux density includes: The heat transfer rate from the arc column to the anode contact surface is determined using the anode heat flux density; the arc burning time is recorded, and the cumulative amount of heat received by the anode contact is calculated using the heat transfer rate. The anode input energy is calculated based on the cumulative amount of heat received by the anode contact; the thermal effect of the anode input energy on the anode contact surface is evaluated to form a heat distribution result; and the anode thermal intensity is calculated based on the heat distribution result.

5. The method for identifying the erosion state of high-voltage DC contactor contacts based on multi-feature maps according to claim 3, characterized in that, Obtaining the electron emission state of the cathode arc region and calculating the cathode thermal intensity includes: Obtain the electron emission state of the cathode arc region and calculate the number of electrons emitted; determine the energy release rate of the cathode region using the number of electrons emitted; calculate the cathode heat input value based on the energy release rate of the cathode region. The degree of heat accumulation in the cathode region is calculated using the cathode heat input value; the intensity of cathode thermal effect is determined based on the degree of heat accumulation in the cathode region.

6. The method for identifying the erosion state of high-voltage DC contactor contacts based on multi-feature maps according to claim 1, characterized in that, Step S3, which assesses the contact erosion loss intensity based on the arc energy, includes: The arc energy is converted into a contact temperature field. When the temperature of the contact temperature field is greater than the preset melting point threshold, the contact material is determined to be in a melting state. The degree of melting is assessed based on the melting state of the contact material. The range of the molten pool on the contact surface is marked based on the degree of melting. The migration direction of the molten material within the molten pool range on the contact surface is identified. The amount of molten material is calculated along the migration direction of the molten material, and the amount of molten material is used to calculate the material loss degree on the contact surface; the contact erosion loss intensity is evaluated based on the material loss degree on the contact surface.

7. The method for identifying the erosion state of high-voltage DC contactor contacts based on multi-feature maps according to claim 6, characterized in that, The range of the molten pool on the contact surface is marked according to the degree of melting, including: Calculate the melting temperature based on the degree of melting, and determine the phase transformation state of the material based on the melting temperature; calculate the proportion of the contact material that changes from solid to liquid based on the phase transformation state of the material, and mark the position of the solid-liquid interface on the contact surface; The contact surface melting zone is divided according to the location of the solid-liquid phase interface on the contact surface, and the range of the molten pool on the contact surface of the melting zone is calculated at the same time.

8. The method for identifying the erosion state of high-voltage DC contactor contacts based on multi-feature maps according to claim 1, characterized in that, In step S4, the contact erosion level is mapped to the contact erosion node in the erosion multi-feature map, and the contact erosion state identification result is output, including: Erosion level labels are generated based on the contact erosion level; the erosion level labels are then associated with and mapped to contact erosion nodes in the erosion multi-feature map to determine the corresponding target erosion nodes. Write the erosion level label to the target erosion node and update the node attributes of the target erosion node; write the node attributes to the erosion multi-feature map and output the contact erosion status recognition result.

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