Multi-dimensional evaluation method for arc extinguishing performance of high-capacity alternating-current contactor

Abstract

The invention discloses a multi-dimensional evaluation method for arc extinguishing performance of a high-capacity alternating current contactor, relates to the technical field of arc extinguishing performance evaluation, and is used for solving the problem of insufficient evaluation index precision caused by incapability of identifying specific contributions of different structural regions to an arc extinguishing process. The method comprises the following steps: acquiring arc chamber design data and acquiring high-frequency breaking characteristics when a contactor is triggered to judge whether to carry out multi-dimensional evaluation, then calculating a design advantage value based on the design data and a ventilation state, and carrying out combined cutting on the contactor to screen out a plurality of evaluation parts. Current fluctuation, heat dissipation rate and arc duration of each evaluation part are monitored in real time, influence factors on arc extinguishing fluctuation are calculated, weighted scoring is carried out on the evaluation parts in combination with data such as the influence factors, the arc duration, contact resistance and limiting current, arc extinguishing performance scores are output, analysis granularity and pertinence are improved, and the evaluation accuracy is improved. And the accuracy of the scoring result is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of arc extinguishing performance evaluation, and more specifically, to a multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor. Background Art

[0002] AC contactors are widely used control and protection devices in power systems. They frequently carry large current on-off operations during operation, which can easily cause arcing. Especially in large-capacity working environments, strong arcs can not only cause contact welding, increased contact resistance, and increased heat loss, but may even cause equipment burnout or electrical fire accidents. Therefore, the arc extinguishing ability of contactors has become a key performance indicator for measuring their working reliability, safety, and service life.

[0003] The prior art has the following deficiencies: At present, the evaluation of arc extinguishing performance of AC contactors lacks the integrated analysis of arc chamber design parameters and actual operation conditions, making it difficult to accurately map the specific impact of design structure on actual arc extinguishing capacity. It does not consider the multi-point and multi-dimensional fluctuation characteristics in the arc generation process, and cannot identify the specific contribution of different structural areas to the arc extinguishing process, resulting in insufficient accuracy of evaluation indicators. Therefore, a multi-dimensional evaluation method for arc extinguishing performance of large-capacity AC contactors is proposed.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a multi-dimensional evaluation method for the arc extinguishing performance of a large-capacity AC contactor, which solves the problems raised in the above-mentioned background technology by applying regional distribution analysis and a multi-factor scoring mechanism.

[0006] To achieve the above object, the present invention provides the following technical solution: a multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor, comprising S1: accessing arc chamber technical documents to obtain arc chamber design data, when the AC contactor is triggered, recording high-frequency breaking characteristics, and comprehensively considering the arc chamber design data and high-frequency breaking characteristics to select whether to perform multi-dimensional optimization evaluation; S2: Perform multi-dimensional optimization evaluation to calculate the design advantage value of the current arc chamber, detect the ventilation status of the AC contactor in the arc chamber, and perform combined cutting of the AC contactor based on the ventilation status and design advantage value of the AC contactor to screen out multiple groups of evaluation parts; S3: Real-time detection of current fluctuation and heat dissipation rate of each evaluation part, analysis of the influence characteristics of each evaluation part on arc extinguishing fluctuation in the AC contactor and calculation of the influence factor, and monitoring of arc duration of each evaluation part; S4: Score the arc duration of each marked evaluation part in combination with the corresponding part's influencing factor on arc extinguishing fluctuation, collect the contact resistance of each marked evaluation part and the limiting current value when turned on, and obtain the score weight of each evaluation part, and calculate the arc extinguishing performance score of the AC contactor in the current arc chamber by combining the part score and the score weight of each marked evaluation part.

[0007] In a preferred embodiment, the arc chamber design data includes the thermal melting limit of the arc chamber material. By acquiring the material density, specific heat capacity and material thickness, a heat capacity accumulation model is established to determine the arc chamber surface temperature rise and add the initial temperature to obtain the thermal melting limit of the arc chamber material. By setting the standard breaking test circuit and breaking frequency parameters, the device under test is made to perform repeated on-off operations within the set duration, and the total number of breaking times is recorded to obtain the high-frequency breaking characteristics; The thermal melting limit and high-frequency breaking characteristics of the arc chamber material are compared with the corresponding reasonable thresholds to obtain the reasonable design results of the current arc chamber. If the judgment results all indicate that the current arc chamber design is unreasonable, the arc extinguishing performance of the large-capacity AC contactor in the current arc chamber is evaluated as a low score by default. Otherwise, a multi-dimensional optimization evaluation is performed on the large-capacity AC contactor in the current arc chamber.

[0008] In a preferred embodiment, the thermal melting limit and high-frequency breaking characteristics of the arc chamber material are standardized, and the design advantage value is obtained by using the geometric mean method; By setting up a micro airflow sensor on the ventilation path of the arc chamber, the air velocity and flow rate changes are measured, the ventilation status of the AC contactor in the arc chamber is detected, and an effective ventilation judgment model based on gas dynamics is introduced to obtain the gas flux per unit time.

[0009] In a preferred embodiment, the design advantage value and the gas flux per unit time are standardized and substituted into a logistic regression model to obtain a site screening embedding value; Combine and divide the AC contactor to obtain the various parts of the AC contactor, and make a comprehensive calculation based on the ventilation demand index of the parts and the historical damage rate of the parts; According to the material thermal parameters of the part, the expected heat input value per unit time of the part is calculated, and the minimum cooling air flow required is reversed by combining the gas heat exchange model to obtain the ventilation demand index of the part; By retrieving the historical data of the AC contactor, the damage events of each structural part are extracted, and statistics are made separately for each part. The statistical number of damage events occurring in this part in the reference cycle is calculated by ratio with the number of operating cycles to obtain the historical damage rate of the part.

[0010] In a preferred embodiment, the site ventilation demand index and the site historical damage rate are standardized and substituted into the comprehensive risk assessment model to calculate and determine the site activity value corresponding to each site of the AC contactor; The active values ​​of the parts are sorted from small to large according to their numerical values. The part screening embedding value is compared with the preset multiple grouping thresholds through the preset multiple grouping thresholds, and the set of evaluation parts whose grouping thresholds are less than or equal to the current embedding value is selected. Combined with the active value sorting results, all evaluation parts whose grouping thresholds are before the current embedding value in the sorting are selected at the same time.

[0011] In a preferred embodiment, the current fluctuation and heat dissipation rate of each evaluation part are detected in real time by an embedded current sensor array and infrared thermal imaging or a micro-thermocouple array; By collecting the current change sequence within a unit time, setting the sampling period, obtaining continuous current sampling values, and calculating based on the difference and variation analysis model, the current fluctuation is obtained; By detecting the temperature change of each evaluation part within a unit time, setting the detection cycle, obtaining a continuous temperature sequence, subtracting the temperature at the start time of temperature detection from the temperature at the end time of temperature detection, and calculating the ratio with the corresponding detection time interval, the heat dissipation rate is obtained; The current fluctuation and heat dissipation rate are standardized and substituted into the exponential synergy index model to obtain the influencing factor of arc extinguishing fluctuation.

[0012] In a preferred embodiment, the influence factor of the arc extinguishing fluctuation in each evaluation part is compared with a preset influence threshold. If the influence factor of the arc extinguishing fluctuation is greater than or equal to the influence threshold, the influence characteristic of the arc extinguishing fluctuation is judged to be high influence, and the corresponding evaluation part is recorded as a low score evaluation and screened out. Conversely, if the influence factor of the arc extinguishing fluctuation is less than the influence threshold, the influence characteristic of the arc extinguishing fluctuation is judged to be low influence, and the corresponding evaluation part is retained and marked. When the AC contactor is triggered, the arc duration of the marked evaluation position is monitored, the arc establishment and extinction moments of each marked evaluation position at the moment the AC contactor is triggered are obtained, and the arc duration is obtained based on the timestamp difference calculation.

[0013] In a preferred embodiment, the arc duration of each marked evaluation part is combined with the influence factor of the corresponding part on arc extinguishing fluctuation, and then substituted into the parabolic nonlinear fusion model to obtain the score of each marked evaluation part.

[0014] In a preferred embodiment, by applying a stable low voltage to each marked evaluation site and measuring its current, the contact resistance of each marked evaluation site is calculated based on Ohm's law; Combined with the arc chamber material characteristics, a pyrolysis reaction model is established to set the maximum allowable temperature rise, and the limiting current value of each marked evaluation part when it is turned on is calculated; The contact resistance of each marked evaluation part and the limiting current value when conducting are standardized and substituted into the exponential entropy bias model to obtain the scoring weight of each evaluation part.

[0015] In a preferred embodiment, the arc extinguishing performance score of the AC contactor in the current arc chamber is obtained by combining the site scores and score weights of each marked evaluation site through weighted summation.

[0016] Technical effects and advantages of the present invention: 1. The present invention obtains arc chamber design data and collects high-frequency breaking characteristics when the contactor is triggered to determine whether to perform multi-dimensional evaluation, and then calculates the design advantage value based on the design data and ventilation status, and performs combined cutting on the contactor to screen out multiple evaluation parts, and monitors the current fluctuation, heat dissipation rate and arc duration of each evaluation part in real time, calculates the influence factor on the arc extinguishing fluctuation, and performs weighted scoring on the evaluation part based on the influence factor, arc duration, contact resistance, limiting current and other data, outputs the arc extinguishing performance score, improves the analysis granularity and pertinence, and improves the accuracy of the scoring result. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a method flow chart of a multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor.

[0018] Figure 2 This is a method step diagram of the multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Example 1 See also Figure 1 to Figure 2 , a multi-dimensional evaluation method for arc extinguishing performance of large-capacity AC contactors. The specific operation process is as follows: Step S1: Access the arc chamber technical document to obtain the arc chamber design data. When the AC contactor is triggered, record the high-frequency breaking characteristics. Combine the arc chamber design data and the high-frequency breaking characteristics to select whether to perform multi-dimensional optimization evaluation. Arc chamber technical documentation refers to written technical information that systematically describes the arc chamber design principle, structural composition, performance indicators, manufacturing process and test verification data. This document is usually compiled by the arc chamber design unit, manufacturer or standardization organization to guide product design, manufacturing, testing and later optimization. Specifically, it refers to obtaining design description documents, CAD drawings and test records containing arc chamber geometric structure parameters, material thermal performance parameters and electrical test data, etc., which will not be elaborated here; Generally, methods for accessing arc chamber technical documents include, but are not limited to: internal design document management systems (such as PDM / PLM systems), engineering blueprints, CAD drawings and parameter specifications provided by the arc chamber R&D team, design manuals or product description documents provided by arc chamber manufacturers, historical patent documents, and arc chamber structure and performance data disclosed in journal articles, which will not be elaborated here; AC contactor refers to an electromagnetic control device used to remotely connect and disconnect AC power circuits. It has the ability to frequently connect and disconnect and is widely used in motor control, power system automation, load protection and other scenarios. It is mainly based on the electromagnetic drive principle and can achieve on-off control of the main circuit by closing or releasing the moving contact through the electromagnetic coil. Among them, high-frequency disconnection refers to the working mode in which the AC contactor or switch device repeatedly and frequently performs on-off operations within a unit time, and its frequency is significantly higher than the typical on-off frequency of ordinary industrial control operations; Furthermore, the access method generally includes logging into a document management system or database, searching using the keyword "arc chamber design" or a specific project number, downloading from the official website of a standardization organization, or obtaining from databases such as CNKI, IEEE, etc., and the access method is not limited here; Among them, the arc chamber design data includes the thermal melting limit of the arc chamber material; The thermal melting limit of arc chamber materials is the temperature threshold or thermal energy density threshold at which the materials used in the arc chamber begin to undergo irreversible melting, softening, carbonization or structural instability when subjected to the impact of high-temperature arc energy per unit time. It is a critical indicator of the thermophysical properties of arc chamber materials. The acquisition logic is to obtain the material density, specific heat capacity and material thickness, establish a heat capacity accumulation model, determine the arc chamber surface temperature rise and accumulate it with the initial temperature to obtain the thermal melting limit of the arc chamber material; Specifically, the heat capacity accumulation model formula is expressed as: ; In the formula, To heat the arc chamber surface, is the thermal shock energy per unit area, is the material density, is the specific heat capacity, is the material thickness; The initial temperature is obtained by measuring the static surface temperature of the arc chamber structure before power is applied by the experimenter through the thermocouple embedding test method or the high-precision infrared thermal imaging method, and the initial temperature data will not be repeated here; The logic of obtaining the high-frequency breaking characteristics is to set the standard breaking test circuit and breaking frequency parameters, make the device under test perform repeated on-off operations within the set duration, record the total number of breaking times, and obtain the segmented frequency, that is, the high-frequency breaking characteristics; The duration setting is determined by the experimenter based on the target working condition stability requirements and the device thermal failure threshold characteristics to ensure the representativeness and effectiveness of the test results, which will not be elaborated here; The arc chamber material thermal melting limit and high-frequency breaking characteristics are compared with the corresponding reasonable thresholds, specifically: Compare the arc chamber material thermal melting limit with the corresponding thermal melting limit reasonable threshold value. If the arc chamber material thermal melting limit is less than the thermal melting limit reasonable threshold value, it means that the current arc chamber design is unreasonable. Otherwise, the current arc chamber design is reasonable. Compare the high-frequency breaking feature with the corresponding reasonable breaking threshold. If the high-frequency breaking feature is greater than or equal to the reasonable breaking threshold, it means that the current arc chamber design is unreasonable. Otherwise, the current arc chamber design is reasonable. If the judgment results all indicate that the current arc chamber design is unreasonable, the arc extinguishing performance of the large-capacity AC contactor in the current arc chamber is evaluated as low by default. Otherwise, a multi-dimensional optimization evaluation is performed on the large-capacity AC contactor in the current arc chamber. Step S2: Perform multi-dimensional optimization evaluation to calculate the design advantage value of the current arc chamber, detect the ventilation status of the AC contactor in the arc chamber, and perform combined cutting of the AC contactor based on the ventilation status of the AC contactor and the design advantage value to screen out multiple groups of evaluation parts; The current arc chamber calculation design advantage value refers to the comprehensive calculation based on the arc chamber material thermal melting limit and high-frequency breaking characteristics; Specifically, there are three possibilities for the arc chamber material thermal melting limit and high-frequency breaking characteristics under the above expression; Possibility 1: The thermal melting limit of the arc chamber material is greater than or equal to the reasonable threshold of the thermal melting limit, and the high-frequency breaking characteristic is less than the reasonable breaking threshold; corresponding to the reasonable arc chamber design, the thermal melting limit and high-frequency breaking characteristic of the arc chamber material are both reasonable; Possibility 2: The thermal melting limit of the arc chamber material is greater than or equal to the reasonable threshold of the thermal melting limit, and the high-frequency breaking characteristic is greater than or equal to the reasonable breaking threshold; corresponding to the arc chamber design with a reasonable thermal melting limit of the arc chamber material and an unreasonable arc chamber design with an unreasonable high-frequency breaking characteristic; Possibility 3: The thermal melting limit of the arc chamber material is less than the reasonable threshold of the thermal melting limit, and the high-frequency breaking characteristic is greater than or equal to the reasonable breaking threshold; corresponding to the unreasonable arc chamber design for the thermal melting limit of the arc chamber material, and the reasonable arc chamber design for the high-frequency breaking characteristic; Standardize the thermal melting limit and high-frequency breaking characteristics of arc chamber materials; It should be noted that the standardization processing method includes but is not limited to a standard linear transformation based on interval scaling, a Z-Score standardization method based on statistics, or a normalization method based on a nonlinear mapping function. The application method of the standardization processing is not described in detail here; By using the geometric mean method and substituting the arc chamber material's thermal melting limit and high-frequency breaking characteristics, the design advantage value is obtained. The specific formula is as follows: ; In the formula, is the design advantage value, is the standardized value of the arc chamber material thermal melting limit, is the reasonableness mapping value of the high-frequency segmentation feature; Furthermore, the normalized value of the high-frequency break feature is , the reasonableness mapping value of its high-frequency segmentation feature ; Among them, a micro airflow sensor is arranged on the ventilation path of the arc chamber to measure the air velocity and flow rate change, and detect the ventilation status of the AC contactor in the arc chamber; In the embodiment of the present invention, in order to quantitatively evaluate the ventilation state of the AC contactor in the arc chamber, an effective ventilation judgment model based on gas dynamics is introduced. Specifically, the formula used is as follows: ; In the formula, is the gas flux per unit time, is the flow coefficient of the flow structure, is the effective cross-sectional area of ​​the vent or channel, is the pressure difference at both ends of the ventilation path, is the density of the flowing gas; Furthermore, when the gas flux per unit time is greater than or equal to the minimum gas flux per unit time, it is considered that the current arc chamber structure forms an effective ventilation path for the AC contactor, thereby having good arc extinguishing cooling capability; The setting of the unit time is estimated by the experimenters based on the statistical results of arc duration and the duration of the entire arc extinguishing process under typical working conditions, which will not be elaborated here; It should be noted that the gas flux per minimum unit time is determined by calculation and induction by those skilled in the art based on the arc extinguishing heat release model and the gas heat carrying capacity theory as well as multiple sets of typical AC contactor arc extinguishing experimental data, which will not be elaborated here; The design advantage value and the gas flux per unit time were standardized and substituted into the logistic regression model to obtain the site screening embedding value; The standardization process has been described in the above embodiments and will not be described in detail here. It should be noted that the logistic regression model is common knowledge to those skilled in the art and will not be described in detail here; Furthermore, the larger the embedding value of part screening is, the more optional evaluation parts there are; Specifically, the evaluation parts are various parts of the AC contactor; Combine and divide the AC contactor to obtain the various parts of the AC contactor, and make a comprehensive calculation based on the ventilation demand index of the parts and the historical damage rate of the parts; Among them, the part ventilation demand index refers to the minimum unit time gas flow or airflow heat exchange intensity required for a specific structural part to ensure normal heat dissipation or avoid heat accumulation during continuous or high-frequency on-off. Its acquisition logic is to calculate the expected heat input value per unit time of the part based on the material thermal parameters of the part, and combine the gas heat exchange model to reversely infer the minimum cooling air flow required to obtain the part ventilation demand index; The gas heat exchange model is common knowledge to those skilled in the art and will not be described in detail here. Furthermore, the minimum cooling gas flow rate is consistent with the above-mentioned minimum gas flux per unit time, which will not be described in detail here; The historical damage rate of parts refers to the statistical probability of failure phenomena such as heat loss, ablation, carbonization, mechanical wear or structural damage in various structural parts of the AC contactor during long-term operation, which is used to reflect the reliability and stability of each part under actual working conditions. Its acquisition logic is to retrieve the historical data of the AC contactor, extract the damage events of each structural part, and count them separately for each part. The statistical number of damages in the part in the reference cycle is calculated by ratio with the number of operation cycles to obtain the historical damage rate of the part; In order to ensure the fairness of the data and the consistency of the comparison, the statistical period of the historical damage rate is set as a unified reference time period, that is, the same length of historical operating time window or the same number of on-off cycles are selected for all parts to sample the damage data; Furthermore, in the present invention, the reference period can be set according to the average life cycle of the contactor under typical working conditions, or determined by the life cycle test duration recommended by industry standards, to ensure that the statistical basis of the damage rate of each part is consistent and comparable; The ventilation demand index of the parts and the historical damage rate of the parts are standardized and substituted into the comprehensive risk assessment model to determine the corresponding part activity value of each part of the AC contactor; Among them, the standardization process has been described in this example and will not be repeated here; Specifically, the comprehensive risk assessment model is a weighted model, which is common knowledge among those skilled in the art and will not be described in detail here; Among them, the higher the site activity value, the higher the site ventilation demand index and the site historical damage rate, and the higher the demand for gas flux and design advantage value per unit time; Sort the active values ​​of the parts from small to large according to the numerical values, compare the part screening embedded value with the preset multiple grouping thresholds through the preset multiple grouping thresholds, select the set of evaluation parts whose grouping thresholds are less than or equal to the current embedded value, and combine the active value sorting results to select all the evaluation parts whose grouping thresholds are before the current embedded value in the sorting; It should be noted that the number of multiple preset grouping thresholds can be consistent with the number of active values ​​of all current evaluation parts, or can be set to a fixed order of magnitude (such as three levels, five levels, ten levels) or the number of levels divided in proportion to the weight of the part importance according to the actual evaluation dimension; Furthermore, the preset multiple grouping thresholds are obtained by comprehensive evaluation by the experimenters based on the statistical distribution of actual on-off working conditions and the distribution law of typical failure positions, which will not be elaborated here; For example, there are five grouping thresholds corresponding to five groups of evaluation parts, as shown in Table 1: Table 1 Evaluation sites of five groups As can be seen from Table 1 above, the selection of evaluation parts is a dynamic grouping screening process based on the activity value sorting and grouping threshold comparison mechanism, that is, by comparing the activity value of the part to be evaluated with multiple preset grouping thresholds one by one, all parts corresponding to the threshold groups whose activity values ​​are less than or equal to the current embedded value are selected, thereby forming a multi-dimensional and multi-level evaluation part set; Furthermore, the parts included in the AC contactor include but are not limited to the electromagnetic system, which is used to generate the attraction force to drive the movable part to close, including the coil, the iron core, the armature, etc.; the main contact system, which is used to complete the on and off of the main circuit, including the moving contact, the static contact, and the contact bracket; the arc extinguishing system, which quickly extinguishes the arc to prevent the contact from burning, mainly including the arc chamber, the arc extinguishing grid, the arc extinguishing sheet, etc.; the auxiliary contact system, which is used to realize the control circuit signal switching, including the normally open / normally closed auxiliary contact; the insulation system, which is used to provide insulation and support for electrical components, including the plastic shell, the isolating piece, the ceramic base, etc.; the spring mechanism, which is used to provide contact pressure and release the rebound force, such as the tension spring, the compression spring, etc.; the arc extinguishing cover / housing, which is used to close the entire device and protect the internal structure from external contamination or contact; Therefore, the parts 1 to 5 mentioned in the above content may not only have one part, that is, the parts included in the parts 1 to 5 may exceed the evaluation parts in the AC contactor mentioned above; Step S3: Real-time detection of current fluctuation and heat dissipation rate of each evaluation part, analysis of the influence characteristics of each evaluation part in the AC contactor on arc extinguishing fluctuation and calculation of the influence factor, and monitoring of arc duration of each evaluation part; The current fluctuation and heat dissipation rate of each evaluation part are detected in real time through embedded current sensor array and infrared thermal imaging or micro-thermocouple array; Embedded current sensor array refers to a combination of multi-point current monitoring units pre-integrated and installed on the current path of each evaluation part of the AC contactor. Its core is constructed by Hall effect current sensor, micro current transformer (CT) or integrated chip-type current detection module (such as INA series), and is arranged according to the current path structure distribution of multiple parts to form an array detection topology, realizing high-frequency, high-precision and real-time monitoring of current fluctuations at each evaluation part; Infrared thermal imaging or micro-thermocouple array refers to a collection of thermal sensitive elements that synchronously detect the temperature distribution characteristics of multiple evaluation parts of the AC contactor, mainly including: infrared thermal imaging unit array: based on the principle of infrared thermal radiation, non-contact acquisition of the surface temperature field of the target part, suitable for arrangement in an area that does not interfere with the switch structure; micro-thermocouple array: such as K-type or T-type micro-thermocouples, contact monitoring of temperature changes by attachment, suitable for arrangement on a metal casing, fixed bracket or support sheet that does not affect the contact performance; The logic of obtaining current fluctuation is to obtain the current fluctuation by collecting the current change sequence within a unit time, setting the sampling period, obtaining the continuous current sampling value, and calculating based on the difference and variation analysis model; It should be noted that the sampling period refers to the time interval between two consecutive current samplings during the current detection process, which is used to construct a current change sequence within a unit time; the sampling period is determined by those skilled in the art based on the current response characteristics of the AC contactor under high-frequency disconnection or high-fluctuation conditions, and will not be elaborated here; The logic of obtaining the heat dissipation rate is to detect the temperature change of each evaluation part in unit time, set the detection cycle, obtain the continuous temperature sequence, subtract the temperature at the start time of temperature detection from the temperature at the end time of temperature detection, and calculate the ratio with the corresponding detection time interval to obtain the heat dissipation rate; Among them, the unit time has been described in the above content and will not be repeated here; Furthermore, the detection cycle is consistent with the above-mentioned sampling cycle setting. It can be understood that since the cycle setting is consistent, the evaluation conditions of each evaluation part are consistent, which will not be described in detail here; The current fluctuation and heat dissipation rate are standardized and substituted into the exponential synergy index model to obtain the influencing factor of arc extinguishing fluctuation; Specifically, the index synergy index model formula is expressed as follows:

[0021] In the formula, is the influencing factor of arc extinguishing fluctuation, is the standardized current fluctuation value, is the mapping value of the normalized heat dissipation rate, is the exponential response adjustment coefficient, is a natural constant; The standardized heat dissipation rate is , then the mapping value of the standardized heat dissipation rate ; Furthermore, compared with linear or polynomial functions, the exponential function grows very rapidly at high input values. This rapid growth can very sensitively capture the "high current fluctuation + weak heat dissipation" or "double high" phenomenon, and is suitable for evaluating sudden high-risk areas during arc extinguishing. The core idea of ​​this model is to emphasize the coupled sensitivity of current fluctuation and thermal instability. The exponential function obviously has the ability of synergistic surge. The influence factor of arc extinguishing fluctuation in each evaluation part is compared with the preset influence threshold. If the influence factor of arc extinguishing fluctuation is greater than or equal to the influence threshold, the influence characteristic of arc extinguishing fluctuation is judged to be high influence, and the corresponding evaluation part is recorded as low score evaluation and screened out. On the contrary, if the influence factor of arc extinguishing fluctuation is less than the influence threshold, the influence characteristic of arc extinguishing fluctuation is judged to be low influence, and the corresponding evaluation part is retained and marked. The influence characteristic of arc extinguishing fluctuation is the trend of arc extinguishing stability change caused by current disturbance and heat dissipation imbalance at a certain evaluation part in unit time, reflecting the degree of adverse interference caused by this part to the arc extinguishing process during the operation of the AC contactor. Its value is measured by the influence factor calculated by a specific coupling model (such as an exponential coupling model) based on the standardized current fluctuation value and the heat dissipation rate value. This feature can be used to characterize the "instantaneous instability" of the arc extinguishing environment and to quantify the degree of weakening of the arc extinguishing performance by this part; It should be noted that the impact threshold is set by the experimenters based on the measured data of multiple sets of thermal-electric disturbance joint responses of AC contactors under typical on-off cycles and the response amplitude distribution of each part in historical arc extinguishing abnormal events, after comprehensive evaluation and statistical modeling, and will not be elaborated here; When the AC contactor is triggered, the arc duration of the marked evaluation position is monitored, and the arc duration of the marked evaluation position is obtained by combining the embedded high-speed photoelectric sensor array and the synchronous voltage-current acquisition module; The logic for obtaining the arc duration of the marked evaluation position is to obtain the arc establishment and extinction time of each marked evaluation position at the moment of AC contactor triggering, and calculate based on the timestamp difference to obtain the arc duration; Specifically, the timestamp is intercepted by the experimenter according to the characteristic parameter recognition rules and sampling data timing benchmark established by the arc, which will not be described in detail here; Step S4: Score the arc duration of each marked evaluation part in combination with the influence factor of the corresponding part on the arc extinguishing fluctuation, collect the contact resistance of each marked evaluation part and the limit current value when conducting and obtain the score weight of each evaluation part, and calculate the arc extinguishing performance score of the AC contactor in the current arc chamber by combining the part score and the score weight of each marked evaluation part; The arc duration of each marked evaluation part is combined with the influence factor of the corresponding part on arc extinguishing fluctuation, and then substituted into the parabolic nonlinear fusion model to obtain the score of each marked evaluation part; Among them, the formula of the parabolic nonlinear fusion model is expressed as: ; In the formula, For the The scores of the marked evaluation parts, For the The normalized arc duration map values ​​of the marked evaluation parts, For the The standardized arc extinguishing fluctuation influence factor of the marked evaluation position, and is the nonlinear adjustment factor; Further, suppose there are n marked evaluation sites, i is the i-th marked evaluation site; Among them, The standardized arc duration of each marked evaluation position is , No. Standardized arc duration mapping values ​​of the marked evaluation locations ; Among them, the nonlinear adjustment factor is set by the experimenter according to the actual degree of suddenness or evaluation sensitivity, which will not be elaborated here; Furthermore, the model is derived from the idea of ​​the bivariate parabolic coupling effect, and is highly sensitive to the "coordinated rise of the two", which is conducive to screening out risk-severely coupled areas, and avoids the linear monotonicity of traditional weighting or product methods. The model has the ability to smooth and limit extreme values, avoiding misjudgment due to a single extremely large item raising the score; The logic for obtaining the contact resistance of each marked evaluation part is to apply a stable low voltage to each marked evaluation part and measure its current, and calculate the contact resistance of each marked evaluation part based on Ohm's law; The logic for obtaining the limiting current value when each marked evaluation part is turned on is to combine the arc chamber material characteristics, establish a pyrolysis reaction model to set the maximum allowable temperature rise, and calculate the limiting current value when each marked evaluation part is turned on; Among them, Ohm's law is common knowledge to those skilled in the art, and the unit time has been described in the above content and will not be repeated here; Furthermore, the formula for calculating the limiting current value when each marked evaluation part is turned on is: ; In the formula, To mark the limiting current value when the evaluation part is turned on, is the contact resistance of the part, is the current duration, is the maximum allowable temperature rise of the material, To evaluate the quality of the site, is the specific heat capacity of the material; The contact resistance and the limit current value when conducting of each marked evaluation part are standardized and substituted into the exponential entropy bias model to obtain the score weight of each evaluation part; Among them, the exponential entropy bias model formula is expressed as: ; In the formula, For the The scoring weight of the marked evaluation part, For the The standardized result of the conduction limit current value of each part is For the The standardized result of the contact resistance of each part is a high current value enhancement item to prevent 0 input anomalies. It is an exponential penalty for the high contact resistance feature, which reduces the weight of the high resistance part and highlights the low resistance and strong current-carrying parts. The denominator is added with 1 to prevent zero division or minimum value expansion. The arc extinguishing performance score of the AC contactor in the current arc chamber is obtained by combining the part scores and the score weights of each marked evaluation part through weighted summation; Optionally, multiple scoring criteria or mechanisms may be set for scoring the arc extinguishing performance of the AC contactor in the current arc chamber, and three or five levels may be set to determine the state of the arc extinguishing performance of the current arc chamber, so as to plan or improve subsequent operations; The present invention obtains arc chamber design data and collects high-frequency breaking characteristics when the contactor is triggered to determine whether to perform multi-dimensional evaluation, then calculates the design advantage value based on the design data and ventilation status, and performs combined cutting on the contactor to screen out multiple evaluation parts. The current fluctuation, heat dissipation rate and arc duration of each evaluation part are monitored in real time, and the influence factor on the arc extinguishing fluctuation is calculated. The evaluation part is weightedly scored based on the influence factor, arc duration, contact resistance, limiting current and other data, and the arc extinguishing performance score is output, thereby improving the analysis granularity and pertinence and improving the accuracy of the scoring result.

[0022] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0023] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented by software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state hard disk.

[0024] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0025] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0026] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0027] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0028] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0029] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0030] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks or optical disks.

[0031] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A multi-dimensional evaluation method for arc extinguishing performance of large-capacity AC contactors, characterized by: include: S1: Access the arc chamber technical documents to obtain the arc chamber design data. When the AC contactor is triggered, record the high-frequency breaking characteristics. Based on the arc chamber design data and high-frequency breaking characteristics, choose whether to perform multi-dimensional optimization evaluation. S2: Perform multi-dimensional optimization evaluation to calculate the design advantage value of the current arc chamber, detect the ventilation status of the AC contactor in the arc chamber, and perform combined cutting of the AC contactor based on the ventilation status and design advantage value of the AC contactor to screen out multiple groups of evaluation parts; S3: Real-time detection of current fluctuation and heat dissipation rate of each evaluation part, analysis of the influence characteristics of each evaluation part on arc extinguishing fluctuation in the AC contactor and calculation of the influence factor, and monitoring of arc duration of each evaluation part; S4: Score the arc duration of each marked evaluation part in combination with the corresponding part's influencing factor on arc extinguishing fluctuation, collect the contact resistance of each marked evaluation part and the limiting current value when turned on, and obtain the score weight of each evaluation part, and calculate the arc extinguishing performance score of the AC contactor in the current arc chamber by combining the part score and the score weight of each marked evaluation part.

2. The multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor according to claim 1 is characterized in that: The arc chamber design data includes the thermal melting limit of the arc chamber material. By obtaining the material density, specific heat capacity and material thickness, a heat capacity accumulation model is established to determine the arc chamber surface temperature rise and add it to the initial temperature to obtain the thermal melting limit of the arc chamber material. By setting the standard breaking test circuit and breaking frequency parameters, the device under test is made to perform repeated on-off operations within the set duration, and the total number of breaking times is recorded to obtain the high-frequency breaking characteristics; The thermal melting limit and high-frequency breaking characteristics of the arc chamber material are compared with the corresponding reasonable thresholds to obtain the reasonable design results of the current arc chamber. If the judgment results all indicate that the current arc chamber design is unreasonable, the arc extinguishing performance of the large-capacity AC contactor in the current arc chamber is evaluated as a low score by default. Otherwise, a multi-dimensional optimization evaluation is performed on the large-capacity AC contactor in the current arc chamber.

3. The multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor according to claim 2 is characterized in that: The thermal melting limit and high-frequency breaking characteristics of arc chamber materials are standardized, and the design advantage value is obtained by using the geometric mean method. By setting up a micro airflow sensor on the ventilation path of the arc chamber, the air velocity and flow rate changes are measured, the ventilation status of the AC contactor in the arc chamber is detected, and an effective ventilation judgment model based on gas dynamics is introduced to obtain the gas flux per unit time.

4. The multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor according to claim 3 is characterized in that: The design advantage value and the gas flux per unit time were standardized and substituted into the logistic regression model to obtain the site screening embedding value; Combine and divide the AC contactor to obtain the various parts of the AC contactor, and make a comprehensive calculation based on the ventilation demand index of the parts and the historical damage rate of the parts; According to the material thermal parameters of the part, the expected heat input value per unit time of the part is calculated, and the minimum cooling air flow required is reversed by combining the gas heat exchange model to obtain the ventilation demand index of the part; By retrieving the historical data of the AC contactor, the damage events of each structural part are extracted, and statistics are made separately for each part. The statistical number of damage events occurring in this part in the reference cycle is calculated by ratio with the number of operating cycles to obtain the historical damage rate of the part.

5. The multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor according to claim 4 is characterized in that: The ventilation demand index of the parts and the historical damage rate of the parts are standardized and substituted into the comprehensive risk assessment model to determine the corresponding part activity value of each part of the AC contactor; The active values ​​of the parts are sorted from small to large according to their numerical values. The part screening embedding value is compared with the preset multiple grouping thresholds through the preset multiple grouping thresholds, and the set of evaluation parts whose grouping thresholds are less than or equal to the current embedding value is selected. Combined with the active value sorting results, all evaluation parts whose grouping thresholds are before the current embedding value in the sorting are selected at the same time.

6. The multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor according to claim 1 is characterized in that: The current fluctuation and heat dissipation rate of each evaluation part are detected in real time through embedded current sensor array and infrared thermal imaging or micro-thermocouple array; By collecting the current change sequence within a unit time, setting the sampling period, obtaining continuous current sampling values, and calculating based on the difference and variation analysis model, the current fluctuation is obtained; By detecting the temperature change of each evaluation part within a unit time, setting the detection cycle, obtaining a continuous temperature sequence, subtracting the temperature at the start time of temperature detection from the temperature at the end time of temperature detection, and calculating the ratio with the corresponding detection time interval, the heat dissipation rate is obtained; The current fluctuation and heat dissipation rate are standardized and substituted into the exponential synergy index model to obtain the influencing factor of arc extinguishing fluctuation.

7. The multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor according to claim 6 is characterized in that: The influence factor of arc extinguishing fluctuation in each evaluation part is compared with the preset influence threshold. If the influence factor of arc extinguishing fluctuation is greater than or equal to the influence threshold, the influence characteristic of arc extinguishing fluctuation is judged to be high influence, and the corresponding evaluation part is recorded as low score evaluation and screened out. On the contrary, if the influence factor of arc extinguishing fluctuation is less than the influence threshold, the influence characteristic of arc extinguishing fluctuation is judged to be low influence, and the corresponding evaluation part is retained and marked. When the AC contactor is triggered, the arc duration of the marked evaluation position is monitored, the arc establishment and extinction moments of each marked evaluation position at the moment the AC contactor is triggered are obtained, and the arc duration is obtained based on the timestamp difference calculation.

8. The multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor according to claim 7 is characterized in that: The arc duration of each marked evaluation part is combined with the influencing factor of the corresponding part on arc extinguishing fluctuation after being standardized and substituted into the parabolic nonlinear fusion model to obtain the score of each marked evaluation part.

9. The multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor according to claim 8, characterized in that: By applying a stable low voltage to each marked evaluation site and measuring its current, the contact resistance of each marked evaluation site is calculated based on Ohm's law; Combined with the arc chamber material characteristics, a pyrolysis reaction model is established to set the maximum allowable temperature rise, and the limiting current value of each marked evaluation part when it is turned on is calculated; The contact resistance of each marked evaluation part and the limiting current value when conducting are standardized and substituted into the exponential entropy bias model to obtain the scoring weight of each evaluation part.

10. The multi-dimensional evaluation method for arc extinguishing performance of a large-capacity AC contactor according to claim 9, characterized in that: The arc extinguishing performance score of the AC contactor in the current arc chamber is obtained by combining the site scores and score weights of each marked evaluation site through weighted summation.

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