Method and device for detecting electric contact performance of power connector for metro vehicle

Abstract

The invention discloses a method and a device for detecting the electrical contact performance of a power connector for a metro vehicle, and relates to the related field of rail transit electrical equipment state detection technologies, the method adopts a four-wire method to accurately measure the contact resistance of the power connector when the metro vehicle is in a shutdown or maintenance state, and the electrical contact performance of the power connector is detected. The influence of the lead resistance on the test result is eliminated; synchronously measuring the environment temperature, and performing normalization processing on the measurement result at the same temperature based on the resistivity temperature coefficient; and comparing the normalized contact resistance value with a preset degradation threshold value, and dividing the electrical contact performance into four grades of good, observation, serious degradation and failure according to a threshold value interval, thereby realizing quantitative evaluation and state grading of the electrical contact performance of the power connector. According to the method, the detection precision and the anti-interference capability can be effectively improved, the operation is simple and convenient, and data support is provided for predictive maintenance and overhaul decision of the power connector, so that the reliability and the safety of metro vehicle operation are improved.

Description

Technical Field

[0001] This application relates to the field of condition monitoring technology for rail transit electrical equipment, and in particular to a method and device for testing the electrical contact performance of power connectors for subway vehicles. Background Technology

[0002] Power connectors are key components of the power transmission system in rail transit vehicles, and their reliability is directly related to the operational safety of trains. In actual operation, power connectors are subjected to the combined effects of current load, mechanical vibration, and environmental stress for extended periods. The electrical contact parts are prone to deterioration such as wear, fatigue, oxidation, and ablation, leading to increased contact resistance and abnormal temperature rise at the contact points. In severe cases, this can cause major safety accidents such as power connector burnout, melting, or even fire.

[0003] Currently, the maintenance of power connectors mainly relies on periodic inspections and reactive replacements, lacking effective online condition monitoring and early fault warning methods. Traditional testing methods are mostly limited to macroscopic inspections, unable to accurately determine the stage of degradation, easily leading to under-maintenance or over-maintenance. Therefore, there is an urgent need for a method to test the contact performance of the electrical contacts of power connectors. Summary of the Invention

[0004] To address the technical problems of the prior art, this application provides a method and apparatus for testing the electrical contact performance of power connectors for subway vehicles. By accurately measuring the contact resistance of the power connector and combining the relationship between the contact resistance and the degree of degradation, the degradation degree of the electrical contact of the power connector can be detected.

[0005] This application provides a method for testing the electrical contact performance of a power connector for subway vehicles, including: Step S10: With the vehicle stopped or under maintenance, the detection system is wired, the circuit is debugged, and the background noise is measured. Step S20: After the detection system is debugged, the contact resistance of the power connector for subway vehicles is detected by the four-wire method, and the ambient temperature during the measurement is recorded simultaneously. Step S30: Analyze and process the recorded power connector contact resistance and temperature data; Step S40: Compare the processed power connector contact resistance test results with the degradation threshold to evaluate the electrical contact performance of the power connector, infer the change in the tested power connector contact resistance, and output the state evaluation results of the automotive power connector electrical contact body.

[0006] Furthermore, the wiring of the detection system in step S10 includes the following steps: Step S11: Connect the two ends of the electrical contact of the power connector to the test probes of the DC resistance tester, and adjust and calibrate the DC resistance tester. Step S12: After debugging, test and record the background noise under no-load conditions.

[0007] Furthermore, in step S20, the test object for the contact resistance of the power connector is the power connector at the end of the subway car and the connecting cables at both ends. The contact resistance characterizes the contact performance of the power connector, which has the characteristics of high precision, anti-interference and simple operation. The test method for the contact resistance of power connectors is the four-wire method: Four wires are used to connect the electrical contact, two of which are used to apply current and the other two are used to measure voltage, forming an independent circuit. This connection method can eliminate the influence of the test system, the resistor under test, and the lead resistance on the test results, thereby improving the accuracy of the test. Compared with the traditional two-wire resistance test method, the four-wire resistance test has higher accuracy and stability. The contact resistance of the power connector is recorded by measuring the contact resistance of the electrical contact body three times on each side using a DC resistance meter, and taking the arithmetic mean of the measured values ​​as the judgment parameter. At the same time, the test data and ambient temperature are recorded.

[0008] Furthermore, in step S30, to reduce experimental error, the average value of three measurements of the contact resistance of the electrical contact body on both the front and back sides is calculated, and the average value is used as the experimental result. Simultaneously, to reduce the influence of temperature on the detection results, the experimental results are normalized to the same temperature, as shown below: While detecting contact resistance, temperature was also detected and recorded, and the test results were normalized using a formula:

[0009] in, These are contact resistance values ​​after normalization at the same temperature. This is the average value after measuring the contact resistance of the electrical contact body three times on each side. The resistivity temperature coefficient of the connector. Temperature during contact resistance measurement The normalized temperature value.

[0010] Furthermore, in step S40, based on the change in the contact resistance of the power connector and the contact resistance threshold... , , An evaluation was conducted to obtain the condition assessment results of the automotive power connector electrical contacts, including: When the processed contact resistance value is less than the first threshold At that time, it was determined that the power connector had good contact performance; When the processed contact resistance value is greater than or equal to the first threshold And less than or equal to the second threshold At this time, it is determined that the contact performance of the power connector needs to be observed; When the processed contact resistance value is greater than the second threshold And less than or equal to the third threshold At that time, it was determined that the contact performance of the power connector was severely deteriorated; When the processed contact resistance value is greater than the third threshold When this occurs, it is determined that the power connector contact performance has failed; Determine the need for maintenance or replacement based on the electrical contact performance evaluation results of the power connectors for subway vehicles, based on their current deterioration status.

[0011] This application also provides a device for testing the electrical contact performance of power connectors for subway vehicles, including a DC resistance tester, a test cable, a temperature detection module, and an information processing module: The DC resistance tester is a micro ohmmeter, which is connected to both ends of the power connector and is used to test contact resistance parameters; The test cable is used to connect the electrical contacts in the power connector to the DC resistance tester; The temperature detection module uses a temperature recorder to monitor the real-time ambient temperature and record the temperature data; The information processing module is a computer that receives real-time data collected by the DC resistance detector and the temperature detection module, extracts features from contact resistance and temperature-related parameters, and plots change curves.

[0012] This application discloses the following technical effects: This application proposes a method and device for testing the electrical contact performance of power connectors for subway vehicles. By accurately measuring the contact resistance of power connectors for subway vehicles, maintenance recommendations are upgraded from experience-based judgments to data-driven quantitative classifications. This method has advantages such as high precision, anti-interference, and ease of operation, providing a solid basis for predictive maintenance, optimizing the allocation of maintenance resources, and improving the stability and safety of train operation. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Flowcharts are used in this application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed precisely in sequence. Instead, various steps can be processed in reverse order or simultaneously as needed. Furthermore, other operations can be added to these processes, or one or more steps can be removed from these processes.

[0014] Figure 1 This is a flowchart illustrating a method for testing the electrical contact performance of a power connector for subway vehicles, provided in an embodiment of this application.

[0015] Figure 2 This application provides a schematic diagram of the resistance detection principle of a method for testing the electrical contact performance of a power connector for subway vehicles.

[0016] Figure 3 This is a schematic diagram of a power connector electrical contact performance testing device for subway vehicles, provided as an embodiment of this application. Detailed Implementation

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application.

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description of this application will be provided in conjunction with the accompanying drawings. The described embodiments should not be considered as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] In the following description, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or modules not explicitly listed or inherent to such processes, methods, products, or devices. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only.

[0020] Example 1: This application provides a method for testing the electrical contact performance of automotive power connectors, such as... Figure 1 As shown, the method includes: Step S10: With the vehicle stopped or under maintenance, connect the testing system, debug the circuit, and then measure the background noise.

[0021] In this embodiment, the wiring and circuit debugging process of the power connector electrical contact detection system includes the following steps: Step S11: Connect the two ends of the electrical contact of the power connector to the test probes of the DC resistance tester, and adjust and calibrate the DC resistance tester. Step S12: After debugging, test and record the background noise under no-load conditions.

[0022] Step S20: After the detection system is debugged, the contact resistance of the power connector for subway vehicles is detected by the four-wire method, and the ambient temperature during the measurement is recorded simultaneously.

[0023] In this embodiment, the test object for the contact resistance of the power connector is the power connector at the end of the subway car and the connecting cables at both ends. The contact resistance is used to characterize the contact performance of the power connector. The test method for connector contact resistance is the four-wire method, such as... Figure 2 As shown, its principle is: Four-wire resistance testing uses four wires to connect the two ends of the electrical contacts of the power connector. Two wires are used to apply current, and the other two are used to measure voltage, forming an independent circuit. This connection method can eliminate the influence of the test system, the resistor under test, and the lead resistance on the test results, thereby improving the accuracy of the test. Compared with the traditional two-wire resistance testing method, four-wire resistance testing has higher accuracy and stability. The contact resistance of the power connector is recorded by measuring the contact resistance of the electrical contact body three times on each side using a DC resistance meter, and taking the arithmetic mean of the measured values ​​as the judgment parameter. At the same time, the test data and ambient temperature are recorded.

[0024] Step S30: Analyze and process the recorded power connector contact resistance and temperature data.

[0025] In this embodiment, after the contact resistance test of the power connector electrical contact body is completed, the contact resistance parameters are analyzed and processed in conjunction with the test temperature, including: To reduce the impact of temperature on the test results, the test results are normalized to the same temperature, as shown below: While detecting contact resistance, temperature was also detected and recorded, and the test results were normalized using a formula:

[0026] in, These are contact resistance values ​​after normalization at the same temperature. This is the average value after measuring the contact resistance of the electrical contact body three times on each side. The resistivity temperature coefficient of the connector. Temperature during contact resistance measurement The normalized temperature value.

[0027] Step S40: Compare the processed power connector contact resistance test results with the degradation threshold to evaluate the electrical contact performance of the power connector, infer the change in the tested power connector contact resistance, and output the state evaluation results of the automotive power connector electrical contact body.

[0028] In this embodiment, the processed test results are compared with the degradation threshold to evaluate the electrical contact performance of the power connector and to give the state evaluation results of the tested power connector electrical contact. The degradation threshold is obtained through prior vibration simulation tests under complex operating conditions. For the detection and condition assessment of electrical contact performance under complex stress in automotive power connectors, the contact resistance variation law is compared with the degradation process of the connector's electrical contacts to extract the contact resistance threshold during the degradation process. , , It is targeted and practical.

[0029] Based on the change in contact resistance of the power connector and the contact resistance threshold , , An evaluation was conducted to obtain the assessment results of the electrical contact condition of the automotive power connector, including: When the processed contact resistance value is less than the first threshold At that time, it was determined that the power connector had good contact performance; When the processed contact resistance value is greater than or equal to the first threshold And less than or equal to the second threshold At this time, it is determined that the contact performance of the power connector needs to be observed; When the processed contact resistance value is greater than the second threshold And less than or equal to the third threshold At that time, it was determined that the contact performance of the power connector was severely deteriorated; When the processed contact resistance value is greater than the third threshold When this occurs, it is determined that the power connector contact performance has failed; Determine the need for maintenance or replacement based on the electrical contact performance evaluation results of the power connectors for subway vehicles, based on their current deterioration status.

[0030] Example 2: The power connector electrical contact performance testing device for subway vehicles provided in this embodiment of the invention can execute the power connector electrical contact performance testing method for subway vehicles provided in any embodiment of the invention, such as... Figure 3 As shown, it includes a DC resistance meter, a test cable, a temperature detection module, and an information processing module: The DC resistance tester is a micro ohmmeter, which is connected to both ends of the power connector and is used to test contact resistance parameters; The test cable is used to connect the electrical contacts in the power connector to the DC resistance tester; The temperature detection module uses a temperature recorder to monitor the real-time ambient temperature and record the temperature data; The information processing module is a computer that receives real-time data collected by the DC resistance detector and the temperature detection module, extracts features from contact resistance and temperature-related parameters, and plots change curves.

[0031] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application. In some cases, the actions or steps described in this application can be performed in a different order than that shown in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. A method of detecting electrical contact performance of a power connector for a subway vehicle, characterized by, The method comprises: Step S10, in the vehicle stop or maintenance state, the detection system wiring, debugging circuit after measuring background noise; Step S20, after the detection system debugging, the contact resistance of the power connector for the subway vehicle is detected by four-wire method, and the ambient temperature during measurement is recorded synchronously; Step S30, the recorded power connector contact resistance and temperature data are analyzed and processed; Step S40, the processed power connector contact resistance test results are compared with the degradation threshold, the electrical contact performance of the power connector is evaluated, the change of the tested power connector contact resistance is inferred, and the state evaluation result of the electrical contact body of the vehicle power connector is output.

2. The method for detecting the electrical contact performance of a power connector for a subway vehicle according to claim 1, characterized in that, In step S10, the detection system wiring comprises the following steps: Step S11, connecting the electrical contact body of the power connector to the detection pen of the direct current resistance tester, and debugging and correcting the direct current resistance tester; Step S12, after debugging, test and record the background noise in the no-load state.

3. The method for detecting the electrical contact performance of a power connector for a subway vehicle according to claim 1, characterized in that, In step S20, the contact resistance measurement of the power connector for the subway vehicle adopts Kelvin four-wire method, and four wires are used to connect the electrical contact body, two of which are used to apply current, and the other two are used to measure voltage.

4. The method for detecting the electrical contact performance of a power connector for a subway vehicle according to claim 1, characterized in that, In step S20, the positive and negative contact resistances of the electrical contact body of the power connector for the subway vehicle are measured for three times, and the arithmetic mean of the test results is taken as the judgment parameter.

5. The method for detecting the electrical contact performance of a power connector for a subway vehicle according to claim 1, wherein In step S30, the data is normalized by the following formula: wherein, is the contact resistance value normalized at the same temperature, is the average of the three measurements of the positive and negative contact resistance of the electrical contact, is the temperature coefficient of resistivity of the power connector, is the temperature at which the contact resistance is measured, is the normalized temperature value.

6. The method for detecting the electrical contact performance of a power connector for a subway vehicle according to claim 1, wherein In step S40, the deterioration threshold is obtained through the vibration simulation test under the complex working condition in advance. For the detection and state determination of the electrical contact performance of the power connector under complex stress, the contact resistance change law is compared with the deterioration process of the power connector electrical contact body, and the contact resistance threshold in the deterioration process is extracted 、 、 .

7. The method for detecting the electrical contact performance of a power connector for a subway vehicle according to claim 6, wherein The contact resistance threshold , , For evaluating the change of the contact resistance of the power connector, the state evaluation result of the power connector electric contact body for vehicle is obtained, comprising: When the processed contact resistance value is less than the first threshold value the power connector contact performance is judged to be good; When the processed contact resistance value is greater than or equal to a first threshold value and less than or equal to a second threshold value the power connector contact performance is determined to be observed. When the processed contact resistance value is greater than a second threshold value and less than or equal to a third threshold value the power connector contact performance is judged to be seriously deteriorated. When the processed contact resistance value is greater than a third threshold value the power connector contact performance is judged to be failed.

8. A device for testing the electrical contact performance of a power connector for subway vehicles, characterized in that, The device is used to implement the electrical contact performance detection method of the power connector for the subway vehicle according to any one of claims 1-7, comprising a direct current resistance tester, a test cable, a temperature detection module and an information processing module: The direct current resistance tester is a micro-ohmmeter connected to both ends of the power connector, used for detecting the contact resistance parameter; The test cable is used to connect the electrical contact body in the power connector and the direct current resistance tester; The temperature detection module applies a temperature recorder to monitor the real-time ambient temperature and record the temperature data; The information processing module is a computer receiving real-time data collected by the direct current resistance tester and the temperature detection module, extracting features of the contact resistance and temperature related parameters, and drawing change curves.

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