Circuit breaker, circuit breaker terminal contact resistance detection device and method

Abstract

This invention discloses a circuit breaker, a device for detecting the contact resistance of circuit breaker terminals, and a method thereof. The device for detecting the contact resistance of circuit breaker terminals includes: a temperature detection module, a current detection module, a data acquisition module, and a data processing module. The temperature detection module is disposed on the surface of the circuit breaker terminals and is used to measure the temperature of the terminals online. The current detection module is used to measure the current flowing through the terminals after power is applied. The data acquisition module is connected to the temperature detection module and the current detection module, and is used to sample the output of the temperature detection module to obtain temperature data, and to sample the output of the current detection module to obtain current data. The data processing module is connected to the data acquisition module and is used to calculate the temperature rise data based on the temperature data, and to calculate the contact resistance of the terminals based on the temperature rise data, current data, and the physical parameters of the terminals. This achieves online detection of the contact resistance of the circuit breaker, enabling real-time monitoring and timely early warning.

Description

Technical Field

[0001] This invention relates to circuit breaker testing technology, and more particularly to a circuit breaker, a device and method for detecting the contact resistance of circuit breaker terminals. Background Technology

[0002] Circuit breakers play a crucial role in power transmission and distribution systems, acting as the carriers of primary current. The contact resistance between the circuit breaker's terminals is closely related to the equipment's lifespan, and its performance is critical to the circuit breaker's electrical reliability. Increased contact resistance at the circuit breaker terminals leads to a rapid rise in internal temperature. If this is not addressed promptly and allowed to worsen, it can affect the performance of electrical connectors and potentially damage the entire electrical system.

[0003] Currently, the methods for testing the reliability of circuit breaker terminal contacts are as follows: after installation, use a dedicated monitoring device; during operation, use an infrared thermometer to monitor the temperature rise of the connectors; or during shutdown maintenance, check for high-temperature scorching marks on the connectors and perform contact resistance testing. The contact resistance of the terminals is generally measured using the voltage drop method. This involves designing a certain current to flow through the contact point, measuring the voltage drop across the contact point, and calculating the resistance based on the voltage drop and current.

[0004] The above-mentioned traditional monitoring methods all operate during the fault deterioration stage, making it impossible to monitor every section of the line in real time and unable to be implemented on a large scale. This results in the inability to provide early warnings of potential dangers and low safety. Furthermore, contact resistance is normally very low, typically in the milliohm range, resulting in a very small voltage drop in the circuit. Meanwhile, the common-mode voltage on the AC live wire branch is also very high, making it inaccurate to estimate contact resistance based on the measured voltage drop. Summary of the Invention

[0005] This invention provides a circuit breaker, a device and method for detecting the contact resistance of circuit breaker terminals, so as to realize the online detection of the contact resistance of the circuit breaker without disconnecting the electrical appliance, thereby achieving real-time monitoring, timely early warning and avoiding the occurrence of electrical accidents.

[0006] In a first aspect, embodiments of the present invention provide a circuit breaker terminal contact resistance detection device, comprising: a temperature detection module, a current detection module, a data acquisition module, and a data processing module;

[0007] The temperature detection module is disposed on the surface of the wiring terminals of the circuit breaker and is used to measure the temperature of the wiring terminals online.

[0008] The current detection module is used to measure the current flowing through the terminal block after power is applied online.

[0009] The data acquisition module is connected to the temperature detection module and the current detection module, and is used to sample the output of the temperature detection module to obtain temperature data, and to sample the output of the current detection module to obtain current data.

[0010] The data processing module is connected to the data acquisition module and is used to calculate the temperature rise data based on the temperature data, and to calculate the contact resistance of the terminal block online based on the temperature rise data, the current data, and the physical parameters of the terminal block.

[0011] Optionally, the temperature detection module includes a temperature sensor, and the current detection module includes a current sensor.

[0012] Optionally, the data processing module includes a first correction unit;

[0013] The first correction unit is used to calculate the contact measurement temperature difference based on the physical parameters of the terminal block and the heat conduction formula, and to correct the temperature rise data.

[0014] Optionally, the data processing module further includes a second correction unit;

[0015] The second correction unit is used to correct the calculated contact resistance of the terminal block according to the correction coefficient, so as to obtain the corrected contact resistance.

[0016] Optionally, the data processing module further includes a judgment unit, a warning unit, and an alarm unit;

[0017] The judgment unit is used to determine the relationship between the difference between the corrected contact resistance and the target contact resistance and the first threshold and the second threshold.

[0018] The early warning unit is used to issue an early warning signal when the difference between the corrected contact resistance and the target contact resistance is greater than or equal to a first threshold and less than a second threshold.

[0019] The alarm unit is used to issue an alarm signal when the difference between the corrected contact resistance and the target contact resistance is greater than or equal to a second threshold.

[0020] In a second aspect, embodiments of the present invention also provide a circuit breaker, including: terminals, a power supply, and a circuit breaker terminal contact resistance detection device as described in any one of the first aspects;

[0021] The terminal block is connected to the power supply.

[0022] The circuit breaker terminal contact resistance detection device includes a temperature detection module, a current detection module, a data acquisition module, and a data processing module; the temperature detection module is disposed on the surface of the circuit breaker terminal; the current detection module is electrically connected to the terminal; the data acquisition module is connected to the temperature detection module and the current detection module; and the data processing module is connected to the data acquisition module.

[0023] Thirdly, embodiments of the present invention also provide a method for detecting the contact resistance of circuit breaker terminals, the method being applied to the circuit breaker terminal contact resistance detection device as described in any one of the first aspects, comprising:

[0024] The first temperature of the temperature detection module located on the surface of the circuit breaker's terminals is obtained;

[0025] After a preset time interval, the second temperature of the temperature detection module is obtained;

[0026] The temperature rise data is calculated based on the first temperature and the second temperature.

[0027] The current data measured by the current detection module is acquired, and the contact resistance of the terminal is calculated online based on the temperature rise data, the current data, and the physical parameters of the terminal.

[0028] Optionally, the step of calculating the temperature rise data based on the first temperature and the second temperature includes:

[0029] The temperature difference of the terminals is calculated based on the first temperature and the second temperature.

[0030] Calculate the contact measurement temperature difference based on the physical parameters of the terminals and the heat conduction formula;

[0031] The temperature rise data is calculated based on the temperature difference between the terminals and the temperature difference measured at the contacts.

[0032] Optionally, after calculating the contact resistance of the terminal based on the temperature rise data and the current data, the method further includes:

[0033] The calculated contact resistance of the terminal block is corrected using a correction factor to obtain the corrected contact resistance.

[0034] Optionally, after correcting the calculated contact resistance of the terminal block using a correction factor to obtain the corrected contact resistance, the method further includes:

[0035] Determine the relationship between the difference between the corrected contact resistance and the target contact resistance and the first threshold and the second threshold;

[0036] If the difference between the corrected contact resistance and the target contact resistance is greater than or equal to the first threshold and less than the second threshold, a warning signal is generated.

[0037] An alarm signal is issued if the difference between the corrected contact resistance and the target contact resistance is greater than or equal to the second threshold.

[0038] This invention provides a circuit breaker terminal contact resistance detection device, comprising: a temperature detection module, a current detection module, a data acquisition module, and a data processing module. The temperature detection module is disposed on the surface of the circuit breaker terminals for online measurement of the terminal temperature. The current detection module is used to online measure the current flowing through the terminals after power is applied. The data acquisition module is connected to the temperature and current detection modules, and is used to sample the output of the temperature detection module to obtain temperature data, and sample the output of the current detection module to obtain current data. The data processing module is connected to the data acquisition module, and is used to calculate temperature rise data based on the temperature data, and to calculate the contact resistance of the terminals online based on the temperature rise data, current data, and the physical parameters of the terminals. This invention solves the problems of inability to detect circuit breaker contact resistance online and inaccurate contact resistance measurements, enabling online detection of circuit breaker contact resistance, improving the accuracy of contact resistance detection, achieving real-time monitoring, timely early warning, and preventing electrical accidents. Attached Figure Description

[0039] Figure 1A This is a schematic diagram of the structure of a circuit breaker terminal contact resistance detection device provided in Embodiment 1 of the present invention;

[0040] Figure 1B This is a schematic diagram of another circuit breaker terminal contact resistance detection device provided in Embodiment 1 of the present invention;

[0041] Figure 2 This is a schematic diagram of the contact temperature conduction of the wiring terminal in Embodiment 1 of the present invention;

[0042] Figure 3 This is a schematic diagram of the structure of a circuit breaker provided in Embodiment 2 of the present invention;

[0043] Figure 4 This is a flowchart illustrating a method for detecting the contact resistance of circuit breaker terminals according to Embodiment 3 of the present invention. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0045] Example 1

[0046] Figure 1A This is a schematic diagram of the structure of a circuit breaker terminal contact resistance detection device provided in Embodiment 1 of the present invention; Figure 1B This is a schematic diagram of another circuit breaker terminal contact resistance detection device provided in Embodiment 1 of the present invention.

[0047] like Figure 1A and Figure 1B As shown, a circuit breaker terminal contact resistance detection device 100 includes: a temperature detection module 110, a current detection module 120, a data acquisition module 130, and a data processing module 140.

[0048] Temperature detection module 110 is disposed on the surface of terminal 210 of circuit breaker and is used to measure the temperature of terminal 210 online.

[0049] The current detection module 120 is used to measure the current flowing through the terminal block 210 after power is applied online;

[0050] The data acquisition module 130 is connected to the temperature detection module 110 and the current detection module 120, and is used to sample the output of the temperature detection module 110 to obtain temperature data, and to sample the output of the current detection module 120 to obtain current data.

[0051] The data processing module 140 is connected to the data acquisition module 130 and is used to calculate the temperature rise data based on the temperature data, and to calculate the contact resistance of the terminal 210 online based on the temperature rise data, current data, and physical parameters of the terminal.

[0052] Optionally, the temperature detection module 110 includes a temperature sensor, and the current detection module 120 includes a current sensor.

[0053] A circuit breaker is a switching device capable of closing, carrying, and interrupting current under normal circuit conditions, and capable of closing, carrying, and interrupting current under abnormal circuit conditions within a specified time. The contact resistance between the terminals of a circuit breaker affects its electrical reliability. If the connection quality between the circuit breaker and external lines is poor, resulting in excessive contact resistance, it will cause the contact points to overheat, and in severe cases, it can damage the circuit.

[0054] The circuit breaker terminal contact resistance detection device 100 is used for online real-time detection of the contact resistance of the terminal 210 of the target circuit breaker. The temperature detection module 110 of the circuit breaker terminal contact resistance detection device 100 is disposed on the surface of the terminal 210 of the circuit breaker. Exemplarily, the temperature detection module 110 includes a temperature sensor. In this embodiment, a high-precision temperature sensor is attached to the surface of the terminal 210, and the temperature sensor is in direct contact with the surface of the terminal 210, achieving accurate online measurement of the actual temperature of the terminal 210. The current detection module 120 of the circuit breaker terminal contact resistance detection device 100 is electrically connected to the terminal 210. Exemplarily, the current detection module 120 includes a current sensor, which measures the current flowing through the terminal 210 after power is applied when the circuit breaker is operating. The data acquisition module 130 converts the received electrical signal into a digital signal. The data acquisition module 130 samples the output of the temperature detection module 110 to obtain temperature data and samples the output of the current detection module 120 to obtain current data. The data processing module 140 calculates the temperature rise data based on the temperature data at preset time intervals. The temperature rise is generated by the work done by the current on the contact resistance of the terminal 210. Based on the temperature rise data and the heat capacity of the contact resistance of the terminal 210, the heat generated by the contact resistance can be calculated. Then, the contact resistance is calculated using Ohm's law and the current data. The heat generated by the contact resistance is related to the physical parameters of the terminal. Heat capacity is the amount of heat required to raise the temperature of a certain amount of material by 1 degree Celsius under certain conditions. Based on the physical parameters of the terminal 210, such as its mass, material, and specific heat, the heat capacity of the contact resistance of the terminal 210 can be calculated.

[0055] The heat Q generated by the contact resistance is calculated based on the temperature rise data at the preset interval and the heat capacity of the contact resistance. Ideally, the heating power P and the contact resistance of the terminal 210 should follow the following formula:

[0056]

[0057] Where Q is the heat generated by the contact resistor from time t1 to time t2, p(t) is the thermal power of the contact resistor, R is the resistance value of the contact resistor, c is the molar specific heat capacity, m is the total mass of the terminal material, and i(t) is the current flowing through the contact resistor.

[0058] After calculating the contact resistance of the terminals, the electrical reliability of the circuit breaker can be determined. The circuit breaker terminal contact resistance detection device is an online detection device. By detecting the contact resistance of the circuit breaker terminals in real time, it can monitor line safety and improve electrical safety.

[0059] This invention provides a circuit breaker terminal contact resistance detection device, comprising: a temperature detection module, a current detection module, a data acquisition module, and a data processing module. The temperature detection module is disposed on the surface of the circuit breaker terminal and is used to measure the temperature of the terminal online. The current detection module is used to measure the current flowing through the terminal after power is applied. The data acquisition module is connected to the temperature detection module and the current detection module, and is used to sample the output of the temperature detection module to obtain temperature data, and to sample the output of the current detection module to obtain current data. The data processing module is connected to the data acquisition module and is used to calculate temperature rise data based on the temperature data, and to calculate the contact resistance of the terminal online based on the temperature rise data, current data, and physical parameters of the terminal. By adding a temperature detection module installed on the surface of the circuit breaker's terminals, the temperature changes of the terminals can be accurately acquired online in real time. Similarly, by adding a current detection module connected to the terminals, the current flowing through them after power is applied can be acquired online in real time. This allows for online monitoring of the circuit breaker's contact resistance changes during operation, solving the problem of previously undetectable contact resistance. Furthermore, by accurately calculating contact resistance changes through monitoring temperature field variations, the problem of inaccurate contact resistance measurements can be addressed. This online detection improves the accuracy of contact resistance measurement, enabling real-time monitoring, timely warnings, and prevention of electrical accidents. The temperature detection module, installed on the terminal surface, offers good installation stability, accurate and reliable temperature acquisition, and is easy to install and remove. It can be installed directly from the circuit breaker manufacturing process, making installation quick and convenient.

[0060] Based on the above embodiments, optionally, the data processing module 140 includes a first correction unit 141;

[0061] The first correction unit 141 is used to calculate the contact measurement temperature difference based on the physical parameters of the wiring terminals and the heat conduction formula, and to correct the temperature rise data.

[0062] In the actual measurement process of the circuit breaker terminal contact resistance detection device, since the terminal is exposed to the air, the heat conduction is not ideal and there is heat loss during the conduction process. In addition, it is connected to a thicker wire, and the heat will be conducted along the wire, causing the temperature detection module 110 to have an error in measuring the temperature of the terminal 210. The measurement data needs to be corrected.

[0063] like Figure 2 As shown, the temperature of the heating point of the terminal block is conducted to the surface of the terminal block, which will cause the temperature to drop. The temperature drop is related to the physical parameters of the terminal block. The contact temperature difference is calculated based on the physical parameters of the terminal block and the heat conduction formula, and the temperature rise data is corrected.

[0064] The formula for heat conduction:

[0065] Where ΔT is the temperature difference between the two ends of the heat-conducting material of the contact, ΔT=T2-T1; T2 is the temperature of the heating point of the contact resistance, in °C; T1 is the temperature measured by the contact temperature detection module, in °C; A is the cross-sectional area of ​​the terminal, in m²; d is the length of the terminal, in meters; λ is the thermal conductivity of the contact terminal, in watts per meter in degrees Celsius, for example, this coefficient for a certain copper material is 381W / (m·K).

[0066] The temperature rise data is corrected by using the temperature difference ΔT between the two ends of the heat-conducting material at the contact point. The contact resistance is then calculated based on the corrected temperature rise data to ensure the accuracy of the contact resistance calculation.

[0067] Optionally, the data processing module 140 may also include a second correction unit 142;

[0068] The second correction unit 142 is used to correct the calculated contact resistance of the terminal 210 according to the correction coefficient, so as to obtain the corrected contact resistance.

[0069] During the measurement and calculation process of the circuit breaker terminal contact resistance detection device, the terminals are connected to wires, which conduct heat. Furthermore, the actual total mass of the materials is greater than the total mass used in the calculation, resulting in the calculated contact resistance being smaller than the actual contact resistance. Therefore, the calculated contact resistance needs to be corrected.

[0070] For example, an empirical formula can be used:

[0071] R 修正 =k·R 测量 +b;

[0072] Among them, R 修正 R represents the corrected contact resistance. 测量 This represents the calculated contact resistance.

[0073] In this embodiment, a correction coefficient k is used for correction. Both the correction coefficient k and the parameter b are obtained from the experimental lookup table obtained by curve fitting of the experimental data.

[0074] Optionally, the data processing module 140 may also include a judgment unit 143, a warning unit 144, and an alarm unit 145;

[0075] The judgment unit 143 is used to judge the relationship between the difference between the corrected contact resistance and the target contact resistance and the first threshold and the second threshold.

[0076] The early warning unit 144 is used to issue an early warning signal when the difference between the corrected contact resistance and the target contact resistance is greater than or equal to a first threshold and less than a second threshold.

[0077] The alarm unit 145 is used to issue an alarm signal when the difference between the corrected contact resistance and the target contact resistance is greater than or equal to a second threshold.

[0078] When the circuit breaker is in operation, the contact resistance within the set range can ensure the normal operation of the circuit breaker. The electrical reliability of the circuit breaker is judged based on the contact resistance of the terminals. Specifically, the judgment unit 143 judges the relationship between the difference between the corrected contact resistance and the target contact resistance and the first threshold and the second threshold to judge the current working status of the circuit breaker. The target contact resistance is the rated value.

[0079] When the difference between the corrected contact resistance and the target contact resistance is greater than or equal to the first threshold and less than the second threshold, the early warning unit 144 issues an early warning signal to remind the staff that the contact resistance of the current circuit breaker has changed and needs to be closely monitored.

[0080] When the difference between the corrected contact resistance and the target contact resistance exceeds the second threshold, the alarm unit 145 issues an alarm signal to remind the staff that the current contact resistance of the circuit breaker has increased significantly, which may affect the electrical reliability of the circuit breaker and requires immediate inspection and troubleshooting.

[0081] In this embodiment, the first threshold is 0.5 times the resistance of the target contact resistance, and the second threshold is N times the resistance of the target contact resistance, where N is greater than or equal to 2.

[0082] By using a circuit breaker terminal contact resistance detection device, the impedance of each section of the line can be monitored in real time. In the event of leakage, maintenance guidance can be provided at any time, thus improving the safety of the electrical system.

[0083] Example 2

[0084] Figure 3 This is a schematic diagram of the structure of a circuit breaker provided in Embodiment 2 of the present invention.

[0085] like Figure 3 As shown, a circuit breaker 200 includes: a terminal block 210, a power supply 220, and a circuit breaker terminal block contact resistance detection device 100.

[0086] Terminal 210 is connected to power supply 220;

[0087] The circuit breaker terminal contact resistance detection device 100 includes a temperature detection module 110, a current detection module 120, a data acquisition module 130, and a data processing module 140. The temperature detection module 110 is disposed on the surface of the terminal 210 of the circuit breaker 200. The current detection module 120 is electrically connected to the terminal 210. The data acquisition module 130 is connected to the temperature detection module 110 and the current detection module 120, and the data processing module 140 is connected to the data acquisition module 130.

[0088] The temperature detection module 110 of the circuit breaker terminal contact resistance detection device 100 is disposed on the surface of the terminal 210 for online measurement of the temperature of the terminal 210. The circuit breaker 200 includes two terminals 210, and correspondingly, the circuit breaker terminal contact resistance detection device 100 has two temperature detection modules 110. The current detection module 120 is electrically connected to the terminal 210 for online measurement of the current flowing through the terminal 210 after power is applied. The data acquisition module 130 samples the output of the temperature detection module 110 to obtain temperature data and samples the output of the current detection module 120 to obtain current data. The data processing module 140 obtains temperature rise data based on the temperature data at preset time intervals, and calculates the contact resistance of the terminal 210 online based on the temperature rise data, current data, and physical parameters of the terminal. The circuit breaker 200 with the circuit breaker terminal contact resistance detection device 100 can detect the contact resistance of the terminal 210 of the circuit breaker 200 in real time online through the circuit breaker terminal contact resistance detection device 100. By continuously measuring the temperature field changes at the circuit breaker terminals online, the changes in the circuit breaker's contact resistance can be monitored, providing timely warnings, improving electrical safety, and preventing electrical accidents.

[0089] Example 3

[0090] Figure 4 This is a flowchart illustrating a method for detecting the contact resistance of circuit breaker terminals according to Embodiment 3 of the present invention. This embodiment is applicable to situations where the contact resistance of circuit breaker terminals is detected online. This method can be executed by a circuit breaker terminal contact resistance detection device.

[0091] like Figure 4 As shown, a method for detecting the contact resistance of circuit breaker terminals specifically includes the following steps:

[0092] Step 310: Obtain the first temperature of the temperature detection module located on the surface of the circuit breaker terminals.

[0093] The temperature detection module is disposed on the surface of the circuit breaker's terminals. For example, the temperature detection module includes a temperature sensor. In this embodiment, a high-precision temperature sensor is mounted on the surface of the terminals, with the sensor in direct contact to achieve accurate measurement of the actual temperature of the terminals. The first temperature of the temperature detection module is acquired at the first moment.

[0094] Step 320: After a preset time interval, obtain the second temperature from the temperature detection module.

[0095] To perform online detection of the contact resistance of the circuit breaker terminals, the temperature measured by the detection module needs to be acquired in real time at set intervals. After a preset interval, the second temperature of the temperature detection module is acquired at a second moment; for example, the preset interval is 5 seconds.

[0096] Step 330: Calculate the temperature rise data based on the first temperature and the second temperature.

[0097] Temperature data is obtained by sampling the output of the temperature detection module. First temperature data and second temperature data are obtained based on the first temperature and the second temperature. Temperature rise data is obtained based on the difference between the second temperature data and the first temperature data.

[0098] Step 340: Obtain the current data measured by the current detection module, and calculate the contact resistance of the terminal block online based on the temperature rise data, current data, and physical parameters of the terminal block.

[0099] The current sensing module is electrically connected to the terminal block. For example, the current sensing module includes a current sensor that measures the current flowing through the terminal block after power is applied when the circuit breaker is operating. The output of the current sensing module is sampled to obtain current data.

[0100] Temperature rise is caused by the work done by the current across the contact resistance of the terminal block. The heat generated by the contact resistance can be calculated based on the temperature rise data and the heat capacity of the terminal block's contact resistance. Then, the contact resistance can be calculated using Ohm's law and the current data. The heat generated by the contact resistance is related to the physical parameters of the terminal block. Heat capacity is the amount of heat required to raise the temperature of a given amount of material by 1 degree Celsius under certain conditions. The heat capacity of the terminal block's contact resistance can be calculated based on its mass, material, and specific heat.

[0101] The heat Q generated by the contact resistance is calculated based on the temperature rise data at the preset interval and the heat capacity of the contact resistance. The heating power P and the contact resistance of the terminal block are related by the following formula:

[0102]

[0103] Where Q is the heat generated by the contact resistor from time t1 to time t2, p(t) is the thermal power of the contact resistor, R is the resistance value of the contact resistor, c is the molar specific heat capacity, m is the total mass of the terminal material, and i(t) is the current flowing through the contact resistor.

[0104] After calculating the contact resistance of the terminals, the electrical reliability of the circuit breaker can be determined. Real-time monitoring of the contact resistance of the circuit breaker terminals at preset intervals allows for real-time monitoring of line safety and improves electrical safety.

[0105] The technical solution of this embodiment provides a method for detecting the contact resistance of circuit breaker terminals. This method involves acquiring a first temperature from a temperature detection module located on the surface of the circuit breaker terminals; acquiring a second temperature from the temperature detection module after a preset time interval; calculating temperature rise data based on the first and second temperatures; acquiring current data measured by a current detection module; and calculating the contact resistance of the terminals online based on the temperature rise data, current data, and the physical parameters of the terminals. By adding a temperature detection module located on the surface of the circuit breaker terminals, the method accurately and in real-time acquires the temperature changes of the terminals online. By adding a current detection module connected to the terminals, the method acquires the current flowing through the terminals after power is applied online, thereby monitoring the changes in contact resistance of the circuit breaker during operation. This achieves online detection of the circuit breaker's contact resistance, solving the problem of the inability to detect contact resistance online. Furthermore, by accurately calculating contact resistance changes through monitoring temperature field changes, the method solves the problem of inaccurate contact resistance measurement. This method achieves online detection of the circuit breaker's contact resistance, improves the accuracy of contact resistance detection, enables real-time monitoring, provides timely warnings, and prevents electrical accidents.

[0106] Based on the above embodiments, step 330 may optionally include:

[0107] Step 331: Calculate the temperature difference between the terminals based on the first temperature and the second temperature.

[0108] Step 332: Calculate the contact measurement temperature difference based on the physical parameters of the wiring terminals and the heat conduction formula.

[0109] Step 333: Calculate the temperature rise data based on the temperature difference between the terminals and the temperature difference measured at the contacts.

[0110] In the actual measurement of the contact resistance of the circuit breaker terminals, since the terminals are exposed to the air and connected to thicker wires, there is heat loss during heat conduction, which causes errors in the temperature measurement of the terminals by the temperature detection module, and the measurement data needs to be corrected.

[0111] like Figure 2As shown, the temperature of the heating point of the terminal block is conducted to the surface of the terminal block, which will cause the temperature to drop. The temperature drop is related to the physical parameters of the terminal block. The contact temperature difference is calculated based on the physical parameters of the terminal block and the heat conduction formula, and the temperature rise data is corrected.

[0112] The formula for heat conduction:

[0113] Where ΔT is the temperature difference between the two ends of the heat-conducting material of the contact, ΔT=T2-T1; T2 is the temperature of the heating point of the contact resistance, in °C; T1 is the temperature measured by the contact temperature detection module, in °C; A is the cross-sectional area of ​​the terminal, in m²; d is the length of the terminal, in meters; λ is the thermal conductivity of the contact terminal, in watts per meter at °C, and this coefficient for copper is 381 W / (m·K).

[0114] The measured temperature difference T of the terminal block is calculated based on the first temperature and the second temperature. The measured temperature difference ΔT of the contact point can be calculated using the above formula. The temperature rise data is obtained based on the measured temperature difference T of the terminal block and the measured temperature difference ΔT of the contact point. The contact resistance is calculated based on the corrected temperature rise data to ensure the accuracy of the contact resistance calculation.

[0115] Optionally, after step 340, the following steps are also included:

[0116] Step 350: Correct the calculated contact resistance of the terminal block using a correction factor to obtain the corrected contact resistance.

[0117] In the process of measuring and calculating the contact resistance of circuit breaker terminals, the terminals are connected to wires, which conduct heat. In addition, the actual total mass of the material is greater than the total mass used in the calculation, resulting in the calculated contact resistance being smaller than the actual contact resistance. Therefore, the calculated contact resistance needs to be corrected.

[0118] For example, an empirical formula can be used:

[0119] R 修正 =k·R 测量 +b;

[0120] Among them, R 修正 R represents the corrected contact resistance. 测量 This represents the calculated contact resistance.

[0121] In this embodiment, a correction coefficient k is used for correction. Both the correction coefficient k and the parameter b are obtained by curve fitting of experimental data and looking up in the experimental lookup table.

[0122] Optionally, after step 350, the following steps are also included:

[0123] Step 360 determines the relationship between the difference between the corrected contact resistance and the target contact resistance and the first threshold and the second threshold; if the difference between the corrected contact resistance and the target contact resistance is greater than or equal to the first threshold and less than the second threshold, then proceed to step 361; if the difference between the corrected contact resistance and the target contact resistance is greater than or equal to the second threshold, then proceed to step 362.

[0124] Step 361: Generate an early warning signal.

[0125] Step 362: Issue an alarm signal.

[0126] When the circuit breaker is in operation, the contact resistance within the set range can ensure the normal operation of the circuit breaker. The electrical reliability of the circuit breaker is judged based on the contact resistance of the terminals. Specifically, the judgment unit judges the relationship between the difference between the corrected contact resistance and the target contact resistance and the first threshold and the second threshold to judge the current working status of the circuit breaker. The target contact resistance is the rated value.

[0127] When the difference between the corrected contact resistance and the target contact resistance is greater than or equal to the first threshold and less than the second threshold, the early warning unit 144 issues an early warning signal to remind the staff that the contact resistance of the current circuit breaker has changed and needs to be closely monitored.

[0128] When the difference between the corrected contact resistance and the target contact resistance exceeds the second threshold, the alarm unit 145 issues an alarm signal to remind the staff that the current contact resistance of the circuit breaker has increased significantly, which may affect the electrical reliability of the circuit breaker and requires immediate inspection and troubleshooting.

[0129] In this embodiment, the first threshold is 0.5 times the resistance of the target contact resistance, and the second threshold is N times the resistance of the target contact resistance, where N is greater than or equal to 2.

[0130] By continuously measuring online, the contact resistance of the circuit breaker terminals can be monitored in real time to ensure it is within the threshold range. In the event of a fault, timely warnings and alarms can be generated, thereby improving the reliability of the power supply equipment.

[0131] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A device for detecting the contact resistance of circuit breaker terminals, characterized in that, include: Temperature detection module, current detection module, data acquisition module, and data processing module; The temperature detection module is disposed on the surface of the wiring terminals of the circuit breaker and is used to measure the temperature of the wiring terminals online. The current detection module is used to measure the current flowing through the terminal block after power is applied online. The data acquisition module is connected to the temperature detection module and the current detection module, and is used to sample the output of the temperature detection module to obtain temperature data, and to sample the output of the current detection module to obtain current data. The data processing module is connected to the data acquisition module and is used to calculate the temperature rise data based on the temperature data, and to calculate the contact resistance of the terminal block online based on the temperature rise data, the current data, and the physical parameters of the terminal block. The data processing module includes a first correction unit; The first correction unit is used to calculate the contact measurement temperature difference based on the physical parameters of the terminal block and the heat conduction formula, and to correct the temperature rise data. The correction of the temperature rise data includes at least the following: correcting the temperature rise data based on the temperature difference between the heating point of the contact resistance and the measurement point of the temperature detection module; The temperature difference between the two ends of the heat-conducting material of the contact is calculated according to the heat conduction formula. The temperature difference between the two ends of the heat-conducting material of the contact is the temperature difference between the heating point of the contact resistance and the measuring point of the temperature detection module. The heat conduction formula includes: Where ΔT is the temperature difference between the two ends of the heat-conducting material of the contact, ΔT=T2-T1; T2 is the temperature of the heating point of the contact resistance, in °C; T1 is the temperature measured by the contact temperature detection module, in °C; A is the cross-sectional area of ​​the terminal block, in m²; d is the length of the terminal block, in meters; λ is the thermal conductivity of the contact terminal block. The data processing module further includes a second correction unit; The second correction unit is used to correct the calculated contact resistance of the terminal block according to the correction coefficient, so as to obtain the corrected contact resistance; The corrected contact resistance includes: R 修正 =k·R 测量 +b; Among them, R 修正 R represents the corrected contact resistance. 测量 This represents the calculated contact resistance; The correction coefficient k and the parameter b are obtained from an experimental lookup table derived by curve fitting of the experimental data.

2. The circuit breaker terminal contact resistance detection device according to claim 1, characterized in that, The temperature detection module includes a temperature sensor, and the current detection module includes a current sensor.

3. The circuit breaker terminal contact resistance detection device according to claim 1, characterized in that, The data processing module also includes a judgment unit, an early warning unit, and an alarm unit; The judgment unit is used to determine the relationship between the difference between the corrected contact resistance and the target contact resistance and the first threshold and the second threshold. The early warning unit is used to issue an early warning signal when the difference between the corrected contact resistance and the target contact resistance is greater than or equal to a first threshold and less than a second threshold. The alarm unit is used to issue an alarm signal when the difference between the corrected contact resistance and the target contact resistance is greater than or equal to a second threshold.

4. A circuit breaker, characterized in that, include: Terminal blocks, power supply, and circuit breaker terminal contact resistance detection device as described in any one of claims 1-3; The terminal block is connected to the power supply. The circuit breaker terminal contact resistance detection device includes a temperature detection module, a current detection module, a data acquisition module, and a data processing module; the temperature detection module is disposed on the surface of the circuit breaker terminal; the current detection module is electrically connected to the terminal; the data acquisition module is connected to the temperature detection module and the current detection module; and the data processing module is connected to the data acquisition module.

5. A method for detecting the contact resistance of circuit breaker terminals, wherein the method is applied to the circuit breaker terminal contact resistance detection device as described in any one of claims 1-3, characterized in that, include: The first temperature of the temperature detection module located on the surface of the circuit breaker's terminals is obtained; After a preset time interval, the second temperature of the temperature detection module is obtained; The temperature rise data is calculated based on the first temperature and the second temperature. The current data measured by the current detection module is acquired, and the contact resistance of the terminal is calculated online based on the temperature rise data, the current data, and the physical parameters of the terminal.

6. The method for detecting the contact resistance of circuit breaker terminals according to claim 5, characterized in that, The temperature rise data calculated based on the first temperature and the second temperature includes: The temperature difference of the terminals is calculated based on the first temperature and the second temperature. Calculate the contact measurement temperature difference based on the physical parameters of the terminals and the heat conduction formula; The temperature rise data is calculated based on the temperature difference between the terminals and the temperature difference measured at the contacts.

7. The method for detecting the contact resistance of circuit breaker terminals according to claim 5, characterized in that, After calculating the contact resistance of the terminal based on the temperature rise data and the current data, the method further includes: The calculated contact resistance of the terminal block is corrected using a correction factor to obtain the corrected contact resistance.

8. The method for detecting the contact resistance of circuit breaker terminals according to claim 7, characterized in that, After correcting the calculated contact resistance of the terminal block using a correction factor to obtain the corrected contact resistance, the method further includes: Determine the relationship between the difference between the corrected contact resistance and the target contact resistance and the first threshold and the second threshold; If the difference between the corrected contact resistance and the target contact resistance is greater than or equal to the first threshold and less than the second threshold, a warning signal is generated. An alarm signal is issued if the difference between the corrected contact resistance and the target contact resistance is greater than or equal to the second threshold.

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