Multi-dimensional Evaluation Method for Arc Extinguishing Performance of High-capacity AC Contactor

Abstract

The present invention discloses a multi-dimensional evaluation method for the arc extinguishing performance of a large-capacity AC contactor, which relates to the technical field of arc extinguishing performance evaluation and is used to solve the problem of insufficient accuracy of evaluation indicators caused by the inability to identify the specific contributions of different structural regions to the arc extinguishing process. By obtaining the arc chamber design data and collecting high-frequency breaking characteristics when the contactor is triggered to determine whether multi-dimensional evaluation is to be carried out, then calculating the design advantage value based on the design data and the ventilation state, and performing combined cutting on the contactor to screen out multiple evaluation parts, the current fluctuations, heat dissipation rates and arc durations of each evaluation part are monitored in real time, the influence factors on the arc extinguishing fluctuations are calculated, and the evaluation parts are weighted and scored in combination with data such as influence factors, arc durations, contact resistances and limit currents, and the arc extinguishing performance score is output, so as to improve the analysis granularity and pertinence and improve the accuracy of the scoring result.

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 the arc extinguishing performance of large-capacity AC contactors. Background Art

[0002] As a control and protection device widely used in the power system, an AC contactor frequently bears large current on-off operations during its working process, and arc phenomena are extremely likely to occur. Especially in a large-capacity working environment, strong arcs will not only cause contact welding, increased contact resistance, and increased heat loss, but may even lead to equipment burnout or electrical fire accidents. Therefore, the arc extinguishing ability of a contactor has become a key performance indicator for measuring its working reliability, safety, and service life.

[0003] The existing technologies have the following deficiencies:

[0004] Currently, the evaluation of the arc extinguishing performance of AC contactors lacks the integrated analysis of the design parameters and operating conditions of the arc chamber, making it difficult to accurately map the specific impact of the design structure on the actual arc extinguishing ability. It does not consider the multi-point and multi-dimensional fluctuation characteristics during the arc generation process and cannot identify the specific contributions of different structural regions to the arc extinguishing process, resulting in insufficient accuracy of the evaluation indicators. Therefore, a multi-dimensional evaluation method for the arc extinguishing performance of large-capacity AC contactors is proposed.

[0005] The above information disclosed in the background art section is only used to enhance the understanding of the background of the present disclosure, and thus it may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0006] 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 large-capacity AC contactors, which solves the problems raised in the above background art by using regional distribution analysis and a multi-factor scoring mechanism.

[0007] To achieve the above object, the present invention provides the following technical solution, a multi-dimensional evaluation method for the arc extinguishing performance of large-capacity AC contactors, including S1: accessing the technical documents of the arc chamber to obtain the design data of the arc chamber. When the AC contactor is triggered, record the high-frequency breaking characteristics. Based on the comprehensive design data of the arc chamber and the high-frequency breaking characteristics, select whether to perform multi-dimensional optimization evaluation;

[0008] S2: If multi-dimensional optimization evaluation is performed, calculate the design advantage value of the current arc chamber, detect the ventilation state of the AC contactor in the arc chamber, and perform combined cutting on the AC contactor based on the comprehensive ventilation state of the AC contactor and the design advantage value, and screen out multiple groups of evaluation parts;

[0009] S3: Detect the current fluctuations and heat dissipation rates of each evaluation part in real time, analyze the influence characteristics of each evaluation part in the AC contactor on the arc extinction fluctuations, calculate the influence factors, and monitor the arc duration of each evaluation part.

[0010] S4: Perform part scoring on the arc duration of each marked evaluation part in combination with the influence factors of the corresponding part on the arc extinction fluctuations, collect the contact resistance of each marked evaluation part and the limit current value during conduction, obtain the scoring weights of each evaluation part, and comprehensively calculate the arc extinction performance score of the AC contactor in the current arc chamber based on the part scores and scoring weights of each marked evaluation part.

[0011] In a preferred embodiment, the arc chamber design data includes the heat 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 surface temperature rise of the arc chamber and accumulate it with the initial temperature to obtain the heat melting limit of the arc chamber material.

[0012] By setting a standard breaking test circuit and breaking frequency parameters, the device under test is made to perform repeated on-off operations within a set duration, and the total number of breakings is recorded to obtain the high-frequency breaking characteristics.

[0013] Compare the heat melting limit of the arc chamber material and the high-frequency breaking characteristics with the corresponding reasonable thresholds respectively to obtain the reasonable result of the current arc chamber design. If the judgment results both indicate that the current arc chamber design is unreasonable, the arc extinction performance of the large-capacity AC contactor in the current arc chamber is defaulted to a low score evaluation. Otherwise, a multi-dimensional optimization evaluation is performed on the large-capacity AC contactor in the current arc chamber.

[0014] In a preferred embodiment, standardize the heat melting limit of the arc chamber material and the high-frequency breaking characteristics, and use the geometric mean method to obtain the design advantage value.

[0015] Measure the air velocity and flow rate changes through a micro air flow sensor set on the ventilation path of the arc chamber, detect the ventilation state of the AC contactor in the arc chamber, and introduce an effective ventilation judgment model based on gas dynamics to obtain the gas flux per unit time.

[0016] In a preferred embodiment, standardize the design advantage value and the gas flux per unit time, and substitute them into the logistic regression model to obtain the part screening embedding value.

[0017] Divide the AC contactor into combinations to obtain each part of the AC contactor, and perform comprehensive calculations based on the part ventilation requirement index and the part historical damage rate.

[0018] According to the material thermal parameters of the part, calculate the expected heat input value per unit time of the part, and combine with the gas heat transfer model to inversely deduce the minimum cooling air flow required to obtain the part ventilation requirement index.

[0019] By retrieving the historical data of the AC contactor, extracting the damage events of each structural part therein, and separately counting them by each part, calculating the ratio of the statistical number of damages occurred in this part during the reference period to the number of operating cycles, the historical damage rate of the part is obtained.

[0020] In a preferred embodiment, the ventilation demand index of the part and the historical damage rate of the part are standardized and substituted into the comprehensive risk assessment model for calculation to determine the part activity value corresponding to each part of the AC contactor;

[0021] Sort the part activity values in ascending order according to the numerical size. Compare the part screening embedding value with a preset multiple of grouping thresholds, select all the evaluation part sets whose grouping thresholds are less than or equal to the current embedding value, and combine with the active value sorting result, and simultaneously select all the evaluation parts whose grouping thresholds are before the current embedding value in the sorting.

[0022] In a preferred embodiment, the current fluctuations and heat dissipation rates of each evaluation part are detected in real time through an embedded current sensor array and infrared thermal imaging or micro-thermocouple array;

[0023] By collecting the current change sequence within a unit time, setting a sampling period, obtaining continuous current sampling values, and calculating based on the difference and variation analysis model, the current fluctuation is obtained;

[0024] By detecting the temperature change amount of each evaluation part within a unit time, setting a detection period, obtaining a continuous temperature sequence, subtracting the temperature at the end of the temperature detection from the temperature at the start of the temperature detection, and calculating the ratio with the corresponding detection time interval, the heat dissipation rate is obtained;

[0025] The current fluctuation and the heat dissipation rate are standardized and substituted into the exponential cooperation index model to obtain the influence factor of the arc extinction fluctuation.

[0026] In a preferred embodiment, compare the influence factor of the arc extinction fluctuation in each evaluation part with a preset influence threshold. If the influence factor of the arc extinction fluctuation is greater than or equal to the influence threshold, it is determined that the influence characteristic of the arc extinction fluctuation is high influence, and the corresponding evaluation part is marked as a low score evaluation and screened out. On the contrary, if the influence factor of the arc extinction fluctuation is less than the influence threshold, it is determined that the influence characteristic of the arc extinction fluctuation is low influence, and the corresponding evaluation part is retained and marked;

[0027] When the AC contactor is triggered, monitor the arc duration of the marked evaluation part, obtain the arc establishment and extinction moments of each marked evaluation part at the moment when the AC contactor is triggered, and calculate based on the time stamp difference to obtain the arc duration.

[0028] In a preferred embodiment, after normalizing the arc duration of each marked evaluation part and combining the influence factor of the corresponding part on the arc extinction fluctuation, the values are substituted into a parabolic non-linear fusion model to obtain the scores of each marked evaluation part.

[0029] In a preferred embodiment, a stable low voltage is applied to each marked evaluation part, and its current is measured, and the contact resistance of each marked evaluation part is calculated based on Ohm's law;

[0030] Combined with the material characteristics of the arc chamber, a pyrolysis reaction model is established to set the maximum allowable temperature rise, and the limit current value when each marked evaluation part is turned on is calculated;

[0031] The contact resistance and the limit current value when each marked evaluation part is turned on are normalized and substituted into an exponential entropy bias model to obtain the score weights of each evaluation part.

[0032] In a preferred embodiment, the arc extinction performance score of the AC contactor in the current arc chamber is obtained by weighted summation of the part scores and score weights of each marked evaluation part.

[0033] Technical effects and advantages of the present invention:

[0034] 1. By obtaining the arc chamber design data and collecting the high-frequency breaking characteristics when the contactor is triggered, the present invention determines whether to perform multi-dimensional evaluation, then calculates the design advantage value based on the design data and ventilation state, performs combined cutting on the contactor, screens out multiple evaluation parts, monitors the current fluctuation, heat dissipation rate and arc duration of each evaluation part in real time, calculates the influence factor on the arc extinction fluctuation, and performs weighted scoring on the evaluation parts by combining data such as the influence factor, arc duration, contact resistance and limit current, and outputs the arc extinction performance score, improving the analysis granularity and pertinence and perfecting the accuracy of the scoring result. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a method flow chart of the multi-dimensional evaluation method for the arc extinction performance of the large-capacity AC contactor of the present invention.

[0036] Figure 2 It is a method step diagram of the multi-dimensional evaluation method for the arc extinction performance of the large-capacity AC contactor of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] Embodiment 1

[0039] Please refer to Figures 1 to 2 , a multi-dimensional evaluation method for the arc extinguishing performance of a large-capacity AC contactor. The specific operation process is as follows:

[0040] 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. Based on the arc chamber design data and the high-frequency breaking characteristics, select whether to perform multi-dimensional optimization evaluation;

[0041] The arc chamber technical document refers to the written technical materials that systematically describe the design principle, structural composition, performance indicators, manufacturing process, and test verification data of the arc chamber. This document is usually compiled by the arc chamber design unit, manufacturer, or standardization organization and is used to guide product design, manufacturing, testing, and later optimization. Specifically, it refers to obtaining design specification documents, CAD drawings, and test records containing arc chamber geometric structure parameters, material thermal performance parameters, and their electrical test data, which will not be elaborated here;

[0042] Generally, the methods for accessing the arc chamber technical document include, but are not limited to: enterprise internal design document management systems (such as PDM / PLM systems), engineering blueprints provided by the arc chamber R & D team, CAD drawings and parameter specifications, design manuals or product description documents provided by the arc chamber manufacturer, historical patent documents, and arc chamber structure and performance data disclosed in journal articles, which will not be elaborated here;

[0043] An AC contactor refers to an electromagnetic control electrical appliance used for remotely connecting and disconnecting AC power circuits. It has the ability to frequently connect and disconnect and is widely used in scenarios such as motor control, power system automation, and load protection. It mainly works based on the electromagnetic drive principle, and the moving contact is attracted or released through an electromagnetic coil to achieve the on-off control of the main circuit;

[0044] Among them, high-frequency breaking refers to the working mode in which an 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;

[0045] Further, the access methods generally include logging in to the document management system or database, retrieving using keywords such as "arc chamber design" or specific project numbers, downloading through the official website of the standardization organization, or obtaining through databases such as CNKI, IEEE, etc. The access methods are not limited herein;

[0046] Among them, the arc chamber design data includes the heat melting limit of the arc chamber material;

[0047] The heat melting limit of the arc chamber material is the temperature threshold or heat energy density threshold at which the material used in the arc chamber begins 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 index of the thermophysical properties of the arc chamber material. The acquisition logic is to establish a heat capacity accumulation model by obtaining the material density, specific heat capacity, and material thickness, determine the surface temperature rise of the arc chamber and accumulate it with the initial temperature to obtain the heat melting limit of the arc chamber material;

[0048] Specifically, the formula expression of the heat capacity accumulation model is:

[0049] ;

[0050] In the formula, is the surface temperature rise of the arc chamber, is the heat shock energy per unit area, is the material density, is the specific heat capacity, is the material thickness;

[0051] Among them, the initial temperature is measured by the experimenter through the method of embedding thermocouples or the high-precision infrared thermal imaging method for the static surface temperature of the arc chamber structure before power-on to obtain the initial temperature data, which will not be elaborated herein;

[0052] The acquisition logic of the high-frequency breaking characteristics is to set a standard breaking test circuit and breaking frequency parameters, enable the device under test to perform repeated on-off operations within the set duration, record the total number of breakings, and obtain the breaking frequency, that is, the high-frequency breaking characteristics;

[0053] Among them, the length of the duration is set by the experimenter according to the stability requirements of the target working condition and the thermal failure threshold characteristics of the device to ensure the representativeness and effectiveness of the test results, which will not be elaborated herein;

[0054] Compare the heat melting limit of the arc chamber material and the high-frequency breaking characteristics with the corresponding reasonable thresholds respectively. Specifically:

[0055] Compare the heat melting limit of the arc chamber material with the corresponding reasonable threshold of the heat melting limit. If the heat melting limit of the arc chamber material is less than the reasonable threshold of the heat melting limit, it indicates that the current arc chamber design is unreasonable; otherwise, the current arc chamber design is reasonable;

[0056] 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 indicates that the current arc chamber design is unreasonable; otherwise, the current arc chamber design is reasonable.

[0057] If all the judgment results indicate that the current arc chamber design is unreasonable, it is defaulted that the arc extinguishing performance of the large-capacity AC contactor in the current arc chamber is evaluated as low; otherwise, a multi-dimensional optimization evaluation is performed on the large-capacity AC contactor in the current arc chamber.

[0058] Step S2: When performing a multi-dimensional optimization evaluation, calculate the design advantage value of the current arc chamber, detect the ventilation state of the AC contactor in the arc chamber, and perform combined cutting on the AC contactor based on the ventilation state of the AC contactor and the design advantage value, and screen out multiple groups of evaluation parts.

[0059] The calculated design advantage value of the current arc chamber refers to the value comprehensively calculated based on the heat melting limit of the arc chamber material and the high-frequency breaking feature.

[0060] Specifically, there are three possibilities for the heat melting limit of the arc chamber material and the high-frequency breaking feature in the above expression.

[0061] Possibility 1: The heat melting limit of the arc chamber material is greater than or equal to the reasonable heat melting limit threshold, and the high-frequency breaking feature is less than the reasonable breaking threshold; corresponding to the arc chamber design where both the heat melting limit of the arc chamber material and the high-frequency breaking feature are reasonable.

[0062] Possibility 2: The heat melting limit of the arc chamber material is greater than or equal to the reasonable heat melting limit threshold, and the high-frequency breaking feature is greater than or equal to the reasonable breaking threshold; corresponding to the arc chamber design where the heat melting limit of the arc chamber material is reasonable and the high-frequency breaking feature is unreasonable.

[0063] Possibility 3: The heat melting limit of the arc chamber material is less than the reasonable heat melting limit threshold, and the high-frequency breaking feature is greater than or equal to the reasonable breaking threshold; corresponding to the arc chamber design where the heat melting limit of the arc chamber material is unreasonable and the high-frequency breaking feature is reasonable.

[0064] Perform standardization processing on the heat melting limit of the arc chamber material and the high-frequency breaking feature.

[0065] It should be noted that the methods of standardization processing include but are not limited to standard linear transformation based on interval scaling, Z-Score standardization method based on statistics, or normalization method based on non-linear mapping function. The application methods of standardization processing will not be elaborated here.

[0066] Using the geometric mean method, substitute the heat melting limit of the arc chamber material and the high-frequency breaking feature to obtain the design advantage value.

[0067] The specific formula is as follows:

[0068] ;

[0069] In the formula, is the design advantage value, is the standardized value of the heat melting limit of the arc chamber material, is the rationality mapping value of the high-frequency breaking characteristic;

[0070] Furthermore, the standardized value of the high-frequency breaking characteristic is , and its rationality mapping value of the high-frequency breaking characteristic ;

[0071] Among them, by means of the micro air flow sensor arranged on the ventilation path of the arc chamber, the air flow velocity and the flow rate change are measured to detect the ventilation state of the AC contactor in the arc chamber;

[0072] 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 is as follows:

[0073] ;

[0074] 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 ventilation hole or channel, is the air pressure difference at both ends of the ventilation path, is the density of the flowing gas;

[0075] 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, so as to have good arc extinguishing and cooling capabilities;

[0076] Among them, for the setting of the unit time, it is deduced by the experimenter based on the statistical results of the arc duration and the duration of the whole arc extinguishing process under typical working conditions, which will not be elaborated here;

[0077] It should be noted that the minimum gas flux per unit time is calculated and summarized by those skilled in the art based on the arc extinguishing heat release model, the gas heat carrying capacity theory and multiple groups of typical AC contactor arc extinguishing experimental data, which will not be elaborated here;

[0078] The design advantage value and the gas flux per unit time are standardized and substituted into the logistic regression model to obtain the part screening embedding value;

[0079] Among them, the standardization process has been described in the above embodiments and will not be elaborated here;

[0080] It should be noted that the logistic regression model is common knowledge to those skilled in the art and will not be elaborated here;

[0081] Furthermore, the larger the embedded value of the part screening, the more optional evaluation parts there are;

[0082] Specifically, the evaluation parts are each part of the AC contactor;

[0083] The AC contactor is combined and segmented to obtain each part of the AC contactor, and comprehensive calculation is performed based on the part ventilation demand index and the part historical damage rate;

[0084] Among them, the part ventilation demand index refers to the minimum unit time gas flow or air flow heat transfer intensity required to ensure normal heat dissipation or avoid heat accumulation during the continuous or high-frequency on-off process of a specific structural part. Its acquisition logic is to calculate the expected heat input value of the part per unit time according to the material thermal parameters of the part, and combine the gas heat transfer model to inversely deduce the required minimum cooling gas flow to obtain the part ventilation demand index;

[0085] Among them, the gas heat transfer model is common knowledge to those skilled in the art and will not be elaborated here;

[0086] Furthermore, the minimum cooling gas flow is the same as the above-mentioned minimum gas flux per unit time and will not be elaborated here;

[0087] The part historical damage rate refers to the statistical occurrence probability of failure phenomena such as thermal damage, ablation, carbonization, mechanical wear, or structural damage in each structural part 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 therein, and perform separate statistics for each part, and calculate the ratio of the statistical number of damages of the part during the reference period to the number of operation cycles to obtain the part historical damage rate;

[0088] Among them, to ensure the fairness of data and the consistency of comparison, the statistical period of the historical damage rate is set as a unified reference time period, that is, an equal-length historical operation time window or an equal number of on-off cycle times are selected for all parts for damage data sampling;

[0089] 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;

[0090] Standardize the ventilation demand index and historical damage rate of each part, and substitute them into the comprehensive risk assessment model for calculation to determine the active value of each part corresponding to the AC contactor;

[0091] Among them, the standardization process has been described in this example and will not be elaborated here;

[0092] Specifically, the comprehensive risk assessment model is a weighted model, which is common knowledge for those skilled in the art and will not be elaborated here;

[0093] Among them, the higher the active value of the part, the higher the ventilation demand index and historical damage rate of the part, and the higher the demand for gas flux and design advantage value per unit time;

[0094] Sort the active values of the parts from small to large according to the numerical size. Compare the screened embedding value of the part with multiple preset grouping thresholds, select the set of evaluated parts where all grouping thresholds are less than or equal to the current embedding value, and combine the active value sorting results to simultaneously select all evaluated parts whose grouping thresholds are before the current embedding value in the sorting;

[0095] It should be noted that the number of multiple preset grouping thresholds can be the same as the number of active values of all current evaluated parts, or can be set to a fixed order of magnitude (such as three levels, five levels, ten levels) according to the actual evaluation dimension or the hierarchical number proportionally divided according to the importance weight of the parts;

[0096] Furthermore, the multiple preset grouping thresholds are comprehensively evaluated 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;

[0097] For example: There are currently five grouping thresholds, corresponding to five groups of evaluated parts, as shown in Table 1 specifically:

[0098] Table 1 Five groups of evaluated parts

[0099] As can be seen from Table 1 above, the selection of evaluated parts is a dynamic grouping and screening process based on the active value sorting and grouping threshold comparison mechanism, that is, by comparing the active values of the parts to be evaluated with multiple preset grouping thresholds one by one, selecting all parts corresponding to the threshold groups covered by all active values less than or equal to the current embedding value, so as to form a multi-dimensional and multi-level set of evaluated parts;

[0100] Furthermore, the components included in the AC contactor include but are not limited to the electromagnetic system, which is used to generate an attractive force to drive the movable part to close, including a coil, an iron core, an armature, etc.; the main contact system, which is used to complete the on-off of the main circuit, including a moving contact, a static contact, a contact bracket; the arc extinguishing system, which quickly extinguishes the arc to prevent the contact from burning, mainly including an arc chamber, an arc extinguishing grid, arc extinguishing plates, etc.; the auxiliary contact system, which is used to realize the signal switching of the control circuit, including normally open / normally closed auxiliary contacts; the insulation system, which provides insulation and support for electrical components, including a plastic case, an isolator, a ceramic base, etc.; the spring mechanism, which provides contact pressure and release resilience for the contacts, such as a tension spring, a compression spring, etc.; the arc extinguishing cover / case, which is used to enclose the entire device to protect the internal structure from external pollution or contact;

[0101] Therefore, there may not be only one component mentioned in the above parts 1 to 5, that is, the components included in parts 1 to 5 may exceed the evaluation components in the above-mentioned AC contactor;

[0102] Step S3: Real-time detect the current fluctuations and heat dissipation rates of each evaluation component, analyze the influence characteristics of each evaluation component in the AC contactor on the arc extinguishing fluctuations and calculate the influence factors, and monitor the arc duration of each evaluation component;

[0103] The current fluctuations and heat dissipation rates of each evaluation component are detected in real time through an embedded current sensor array and infrared thermal imaging or micro-thermocouple array;

[0104] The embedded current sensor array refers to a combination of multi-point current monitoring units pre-integrated and installed on the current paths of each evaluation component of the AC contactor. Its core is constructed by a Hall effect current sensor, a micro current transformer (CT) or an integrated chip type current detection module (such as the INA series), and is arranged according to the current path structures of multiple components to form an array detection topology to achieve high-frequency, high-precision, real-time monitoring of the current fluctuations of each evaluation component;

[0105] The infrared thermal imaging or micro-thermocouple array refers to a set of heat-sensitive elements for synchronously detecting the temperature distribution characteristics of multiple evaluation components of the AC contactor, mainly including: an infrared thermal imaging unit array: based on the principle of infrared thermal radiation, non-contact acquisition of the surface temperature field of the target component, suitable for being arranged in areas that do not interfere with the on-off structure; a micro-thermocouple array: such as a K-type or T-type micro-thermocouple, contact monitoring of temperature changes through an attachment method, suitable for being arranged on a metal shell, a fixed bracket or a support piece that does not affect the contact performance;

[0106] Among them, the acquisition logic of the current fluctuations is to calculate the current fluctuations based on the differential and variation analysis model by collecting the current change sequence within a unit time, setting the sampling period, and obtaining continuous current sampling values;

[0107] 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 the current change sequence within a unit time; this sampling period is determined by those skilled in the art according to the current response characteristics of the AC contactor under high-frequency breaking or high-fluctuation working conditions, and will not be elaborated here;

[0108] The acquisition logic of the heat dissipation rate is to detect the temperature change amount of each evaluation part within a unit time, set the detection period, obtain the continuous temperature sequence, subtract the temperature at the end of the temperature detection from the temperature at the start of the temperature detection, and perform a ratio calculation with the corresponding detection time interval to obtain the heat dissipation rate;

[0109] Among them, the unit time has been described above and will not be elaborated here;

[0110] Furthermore, the detection period is set the same as the above-mentioned sampling period. It can be understood that since the periods are set the same, the evaluation conditions of each evaluation part are the same, and will not be elaborated here;

[0111] Standardize the current fluctuation and the heat dissipation rate, and substitute them into the exponential synergy index model to obtain the influence factor of the arc extinction fluctuation;

[0112] Specifically, the formula of the exponential synergy index model is expressed as follows:

[0113]

[0114] In the formula, is the influence factor of the arc extinction fluctuation, is the standardized current fluctuation value, is the mapped value of the standardized heat dissipation rate, is the exponential response adjustment coefficient, is the natural constant;

[0115] Among them, the standardized heat dissipation rate is , then the mapped value of the standardized heat dissipation rate ;

[0116] 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 the sudden high-risk areas during the arc extinction process. Among them, the core idea of this model is to emphasize the coupling sensitivity between current fluctuation and thermal instability, and the exponential function obviously has the ability of synergistic surge;

[0117] Compare the influencing factors of arc extinction fluctuations in each evaluation part with the preset influence threshold. If the influencing factor of arc extinction fluctuations is greater than or equal to the influence threshold, it is determined that the influencing characteristic of arc extinction fluctuations is high influence, mark the corresponding evaluation part as a low score evaluation and screen it out. On the contrary, if the influencing factor of arc extinction fluctuations is less than the influence threshold, it is determined that the influencing characteristic of arc extinction fluctuations is low influence, retain and mark the corresponding evaluation part;

[0118] The influencing characteristic of arc extinction fluctuations is the change trend of arc extinction stability caused by current disturbance and uneven heat dissipation in a certain evaluation part within a unit time, reflecting the degree of adverse interference of this part on the arc extinction process during the operation of the AC contactor. Its value is measured by the influencing factor calculated through a specific coupling model (such as an exponential coupling model) based on the current fluctuation value and heat dissipation rate value after standardization. This characteristic can be used to characterize the "instantaneous instability" of the arc extinction environment and quantify the degree of weakening of the arc extinction performance of this part;

[0119] It should be noted that the influence threshold is set by the experimenters based on the measured data of the combined thermal-electric disturbance response of multiple groups of AC contactors under typical on-off cycles and the response amplitude distribution of each part in historical arc extinction abnormal events, and is not elaborated here through comprehensive evaluation and statistical modeling;

[0120] When the AC contactor is triggered, monitor the arc duration of the marked evaluation part. Specifically, obtain the arc duration of the marked evaluation part through the joint action of an embedded high-speed optoelectronic sensor array and a synchronous voltage-current acquisition module;

[0121] The acquisition logic of the arc duration of the marked evaluation part is to obtain the arc establishment and extinction moments of each marked evaluation part at the moment when the AC contactor is triggered, and calculate based on the time stamp difference to obtain the arc duration;

[0122] Specifically, the time stamp is intercepted by the experimenters according to the arc establishment characteristic parameter identification rule and the sampling data time sequence reference, and is not elaborated here;

[0123] Step S4: Score each marked evaluation part by combining the arc duration of each marked evaluation part with the influencing factor of arc extinction fluctuations for the corresponding part. Collect the contact resistance and the limit current value during conduction of each marked evaluation part and obtain the scoring weight of each evaluation part. Calculate the arc extinction performance score of the AC contactor in the current arc chamber by comprehensively considering the part scores and scoring weights of each marked evaluation part;

[0124] After standardizing the arc duration of each marked evaluation part in combination with the influencing factor of arc extinction fluctuations for the corresponding part, substitute it into the parabolic non-linear fusion model to obtain the scores of each marked evaluation part;

[0125] Among them, the formula expression of the parabolic non-linear fusion model is:

[0126] ;

[0127] In the formula, is the score of the th marked evaluation part, is the normalized arc duration mapping value of the th marked evaluation part, is the normalized arc extinction fluctuation influence factor of the th marked evaluation part, and are non - linear adjustment factors;

[0128] Furthermore, assume that there are n marked evaluation parts, and i is the i - th marked evaluation part;

[0129] Among them, the normalized arc duration of the th marked evaluation part is , and the normalized arc duration mapping value of the th marked evaluation part is ;

[0130] Among them, the non - linear adjustment factor is set by the experimenter according to the actual emergency degree or evaluation sensitivity, which will not be elaborated here;

[0131] Furthermore, the model is derived from the idea of bivariate parabola coupling effect, is highly sensitive to "the synchronous rise of the two", is beneficial to screening out strongly coupled risk parts, and avoids the linear monotonicity of the traditional weighted or product method. The model has a smoothing limit ability for extreme values and avoids misjudgment due to a single maximum term pulling up the score;

[0132] The acquisition logic of 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;

[0133] The acquisition logic of the limit current value when each marked evaluation part is conducting is to establish a pyrolysis reaction model to set the maximum allowable temperature rise in combination with the material characteristics of the arc chamber, and calculate the limit current value when each marked evaluation part is conducting;

[0134] Among them, Ohm's law is common knowledge for those skilled in the art, and the unit time has been described above, which will not be elaborated here;

[0135] Furthermore, the formula for calculating the limit current value when each marked evaluation part is conducting is:

[0136] ;

[0137] In the formula, To mark the limit current value when the evaluation part is conducting, is the part contact resistance, is the current duration, is the maximum allowable temperature rise of the material, is the quality of the evaluation part, is the specific heat capacity of the material;

[0138] Standardize the contact resistance and the limit current value when conducting of each marked evaluation part, substitute them into the exponential entropy bias voltage model, and obtain the scoring weights of each evaluation part;

[0139] Among them, the formula of the exponential entropy bias voltage model is expressed as:

[0140] ;

[0141] In the formula, is the scoring weight of the th marked evaluation part, is the standardized result of the conduction limit current value of the th part, is the standardized result of the contact resistance of the th part, which is the high current value enhancement term to prevent abnormal 0 input, and is the exponential penalty for the high contact resistance characteristic to reduce the weight of the high resistance part and highlight the low resistance and strong current-carrying parts. Adding 1 to the denominator prevents division by zero or magnification of extremely small values;

[0142] Comprehensively obtain the arc extinguishing performance score of the AC contactor in the current arc chamber by weighted summation of the part scores and scoring weights of each marked evaluation part;

[0143] Optionally, multiple scoring criteria or mechanisms can be set for the arc extinguishing performance score of the AC contactor in the current arc chamber. Three or five gears can be set to determine the state of the arc extinguishing performance of the current arc chamber, so as to plan or improve subsequent operations;

[0144] The present invention obtains the arc chamber design data and collects the high-frequency breaking characteristics when the contactor is triggered to judge whether to perform multi-dimensional evaluation, then calculates the design advantage value based on the design data and the ventilation state, performs combined cutting on the contactor, screens out multiple evaluation parts, real-time monitors the current fluctuations, heat dissipation rates and arc durations of each evaluation part, calculates their influence factors on the arc extinguishing fluctuations, and combines data such as influence factors, arc durations, contact resistances and limit currents to perform weighted scoring on the evaluation parts, output the arc extinguishing performance score, improve the analysis granularity and pertinence, and improve the accuracy of the scoring results.

[0145] The above formulas are all dimensionless and take their numerical values for calculation. The formulas are obtained by collecting a large amount of data for software simulation to get a formula closest to the actual situation. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0146] The above embodiments can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using 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 processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired or wireless (such as infrared, wireless, microwave, etc.) manner. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains a set of one or more available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0147] It should be understood that in various embodiments of the present application, the magnitudes of the serial numbers of the above processes do not mean the order of execution is prior or subsequent. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0148] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0149] Those skilled in the art can clearly understand that for the convenience and conciseness of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0150] In several embodiments provided by 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 merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, 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 displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0151] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0152] In addition, in each embodiment of the present application, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0153] If the functions are implemented in the form of software function 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, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs that can store program codes.

[0154] As described above, it is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A multi-dimensional evaluation method for the arc extinguishing performance of large-capacity AC contactors, characterized in that: Including: S1: Access the technical documents of the arc chamber 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 the high-frequency breaking characteristics, select whether to conduct a multi-dimensional optimization evaluation; Among them, compare the melting heat limit of the arc chamber material and the high-frequency breaking characteristics with the corresponding reasonable thresholds respectively to obtain the reasonable result of the current arc chamber design. 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 defaulted to a low evaluation. Otherwise, conduct a multi-dimensional optimization evaluation on the large-capacity AC contactor in the current arc chamber; S2: If a multi-dimensional optimization evaluation is conducted, calculate the design advantage value of the current arc chamber, detect the ventilation state of the AC contactor in the arc chamber, and combine the ventilation state of the AC contactor and the design advantage value to perform combined cutting on the AC contactor and screen out multiple groups of evaluation parts; Among them, standardize the melting heat limit of the arc chamber material and the high-frequency breaking characteristics, and use the geometric mean method to obtain the design advantage value; S3: Real-time detect the current fluctuation and heat dissipation rate of each evaluation part, analyze the influence characteristics of each evaluation part in the AC contactor on the arc extinguishing fluctuation and calculate the influence factor, and monitor the arc duration of each evaluation part; Among them, compare the influence factor of the arc extinguishing fluctuation in each evaluation part with the preset influence threshold. If the influence factor of the arc extinguishing fluctuation is less than the influence threshold, judge that the influence characteristic of the arc extinguishing fluctuation is low influence, and retain and mark the corresponding evaluation part; S4: Score the arc duration of each marked evaluation part in combination with the influence factor of the arc extinguishing fluctuation of the corresponding part, collect the contact resistance and the limit current value during conduction of each marked evaluation part and obtain the scoring weight of each evaluation part, and comprehensively calculate the arc extinguishing performance score of the AC contactor in the current arc chamber based on the part scores and scoring weights of each marked evaluation part; Among them, the arc chamber design data includes the melting heat limit of the arc chamber material. By obtaining the material density, specific heat capacity and material thickness, establish a heat capacity accumulation model, determine the surface temperature rise of the arc chamber and accumulate it with the initial temperature to obtain the melting heat limit of the arc chamber material; By setting a 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 breakings, and obtain the high-frequency breaking characteristics.

2. The multi-dimensional evaluation method for the arc extinguishing performance of a large-capacity AC contactor according to claim 1, characterized in that: Measure the air velocity and flow rate changes through a micro air flow sensor arranged on the ventilation path of the arc chamber, detect the ventilation state of the AC contactor in the arc chamber, and introduce an effective ventilation judgment model based on gas dynamics to obtain the gas flux per unit time.

3. The multi-dimensional evaluation method for the arc extinguishing performance of a large-capacity AC contactor according to claim 2, characterized in that: Standardize the design advantage value and the gas flux per unit time, and substitute them into the logistic regression model to obtain the part screening embedding value; Perform combined segmentation on the AC contactor to obtain each part of the AC contactor, and perform comprehensive calculation based on the part ventilation requirement index and the part historical damage rate; According to the material thermal parameters of this part, calculate the expected heat input value per unit time of the part, and combined with the gas heat exchange model, inversely deduce the required minimum cooling gas flow rate to obtain the ventilation demand index of the part; By retrieving the historical data of the AC contactor, extract the damage events of each structural part therein, and conduct separate statistics for each part. Calculate the ratio of the statistical number of damages occurred in this part during the reference period to the number of operating cycles to obtain the historical damage rate of the part.

4. The multi-dimensional evaluation method for the arc extinguishing performance of a large-capacity AC contactor according to claim 3, characterized in that: Standardize the ventilation demand index of the part and the historical damage rate of the part, and substitute them into the comprehensive risk assessment model for calculation to determine the part activity value corresponding to each part of the AC contactor; Sort the part activity values in ascending order according to the numerical size. Compare the part screening embedding value with a preset multiple of grouping thresholds, and select all the evaluation part sets whose grouping thresholds are less than or equal to the part screening embedding value. Combining with the sorting result of the activity value, simultaneously select all the evaluation parts whose grouping thresholds are before the part screening embedding value in the sorting.

5. The multi-dimensional evaluation method for the arc extinguishing performance of a large-capacity AC contactor according to claim 1, characterized in that: Use the embedded current sensor array and infrared thermal imaging or micro-thermocouple array to detect the current fluctuation and heat dissipation rate of each evaluation part in real time; By collecting the current change sequence per unit time, set the sampling period to obtain continuous current sampling values, and calculate based on the differential and variation analysis model to obtain the current fluctuation; By detecting the temperature change amount of each evaluation part per unit time, set the detection period to obtain a continuous temperature sequence. Subtract the temperature at the end of the temperature detection from the temperature at the start of the temperature detection, and calculate the ratio with the corresponding detection time interval to obtain the heat dissipation rate; Standardize the current fluctuation and heat dissipation rate, and substitute them into the exponential cooperation index model to obtain the influencing factor of the arc extinction fluctuation; 6. The multi-dimensional evaluation method for the arc extinguishing performance of a large-capacity AC contactor according to claim 5, characterized in that: Compare the influencing factor of the arc extinction fluctuation in each evaluation part with the preset influence threshold. If the influencing factor of the arc extinction fluctuation is greater than or equal to the influence threshold, then judge that the influencing characteristic of the arc extinction fluctuation is high influence, and mark the corresponding evaluation part as a low score evaluation and screen it out; When the AC contactor is triggered, monitor the arc duration of the marked evaluation parts, obtain the arc establishment and extinction moments of each marked evaluation part at the moment when the AC contactor is triggered, and calculate based on the time stamp difference to obtain the arc duration; 7. The multi-dimensional evaluation method for the arc extinguishing performance of a large-capacity AC contactor according to claim 6, characterized in that: After standardizing the arc duration of each marked evaluation part and the influencing factor of the arc extinction fluctuation corresponding to the part, substitute them into the parabolic non-linear fusion model to obtain the score of each marked evaluation part; 8. The multi-dimensional evaluation method for the arc extinguishing performance of a large-capacity AC contactor according to claim 7, characterized in that: 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; Combined with the material characteristics of the arc chamber, establish a pyrolysis reaction model, set the maximum allowable temperature rise, and calculate the limit current value when each marked evaluation part is conducting; Standardize the contact resistance and the limit current value when conducting of each marked evaluation part, and substitute them into the exponential entropy bias voltage model to obtain the score weight of each evaluation part; 9. The multi-dimensional evaluation method for the arc extinguishing performance of a large-capacity AC contactor according to claim 8, characterized in that: Comprehensively calculate the arc extinction performance score of the AC contactor in the current arc chamber by weighted summation of the part scores and score weights of each marked evaluation part.

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