Large-drawer circuit breaker contact temperature automatic detection protection device and method

Abstract

The application relates to the technical field of low-voltage electrical appliance protection, in particular to a large-drawer-type circuit breaker contact temperature automatic detection protection device and method, which comprises a wireless temperature sensing module, a data acquisition and processing host, a pre-warning and tripping control module, and a state indication and communication module; the method realizes graded pre-warning and automatic tripping protection through initialization of operation parameters, periodic acquisition of contact temperature data, environmental temperature compensation correction, multi-stage sensor fault detection and temperature comprehensive judgment; the application realizes online monitoring of key contacts of a circuit breaker, adopts multi-stage judgment logic combining absolute temperature, phase-to-phase temperature difference and temperature rise rate, can automatically trigger circuit breaker tripping in milliseconds, supports remote centralized monitoring and complete data recording, provides support for predictive maintenance and digital management of a power distribution system, and effectively avoids safety accidents such as welding, insulation breakdown and electrical fire caused by contact overheating.

Description

Technical Field

[0001] This invention relates to the field of low-voltage electrical protection technology, specifically to an automatic detection and protection device and method for the contact temperature of large drawer-type circuit breakers. Background Technology

[0002] Large drawer-type circuit breakers are core protection and control components in low-voltage power distribution systems, widely used in data centers, industrial plants, commercial buildings, rail transit, and other critical applications. Their main circuit achieves electrical connection between the drawer unit and the busbar system via plug-in contacts. During long-term operation, factors such as mechanical aging of the plug-in components, attenuation of contact pressure, oxidation and corrosion of contact surfaces, improper installation, and prolonged overload operation can easily lead to an abnormal increase in contact resistance. When a large current flows through, according to Joule's law Q=I... 2 Increased contact resistance (Rt) leads to a large amount of Joule heat generated at the contacts, causing an abnormal temperature rise. Excessive temperature rise not only accelerates the aging of insulation materials and reduces electrical life, but in severe cases, it can also lead to contact welding, insulation breakdown, and even major safety accidents such as electrical fires.

[0003] Currently, the industry mainly relies on the following methods to monitor the contact temperature of drawer-type circuit breakers: (1) Maintenance personnel use handheld infrared thermometers for regular inspections, usually once a day or once a week. This method has significant drawbacks: First, it has poor real-time performance, making it impossible to achieve 24-hour uninterrupted monitoring and difficult to detect sudden temperature rise faults; second, it has low safety, as there is a risk of electric shock when personnel approach the live cabinet for measurement, and the internal contact temperature cannot be measured when the drawer cabinet door is closed, and forcibly opening the door for measurement will damage the insulation environment inside the cabinet; third, data recording relies on manual handwriting, which is prone to errors and cannot form a continuous temperature curve for trend analysis; fourth, the early warning capability is weak, making it difficult to establish a temperature change trend model and unable to achieve early warning of faults.

[0004] (2) Some existing wireless temperature measurement systems only collect and display temperature data, lacking a linkage mechanism with the circuit breaker protection mechanism. Even if an abnormal temperature rise is detected, it can only issue an alarm signal and cannot automatically control the circuit breaker to shut down, requiring manual intervention. In emergency situations, the slow manual response often misses the best protection opportunity, leading to the escalation of the accident.

[0005] (3) Most temperature measurement systems only use absolute temperature thresholds for judgment, lacking a comprehensive analysis of interphase temperature difference and temperature rise rate. In fact, heat generation caused by poor contact often manifests as a temperature of one phase being significantly higher than that of other phases, or a rapid temperature rise in a short period of time. At this time, even if the absolute temperature has not yet reached the danger threshold, there is already a serious safety hazard. A single threshold judgment is prone to missed judgment. Summary of the Invention

[0006] The purpose of this invention is to provide an automatic detection and protection device and method for the contact temperature of large drawer-type circuit breakers, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: Automatic detection and protection device and method for contact temperature of large drawer-type circuit breakers, including: The wireless temperature sensing module is used to be installed at the upper and lower contacts of each phase inside the circuit breaker drawer to collect real-time temperature data of each contact and transmit it wirelessly. The data acquisition and processing host is used to receive temperature data sent by various wireless temperature sensors, execute multi-level temperature judgment logic, and make comprehensive analysis and decisions by combining absolute temperature threshold, phase-to-phase temperature difference and temperature rise rate. The early warning and trip control module is used to drive the local audible and visual alarm based on the decision results of the data acquisition and processing host, and to connect to the circuit breaker shunt trip coil circuit through the control relay contacts to achieve automatic trip protection; The status indication and communication module is used to provide local status display and upload temperature data, alarm information, and tripping events to the background monitoring system.

[0008] Preferably, the wireless temperature sensing module includes multiple miniature wireless temperature sensors, which are respectively installed at the upper and lower contacts of phases A, B, and C. Each sensor is powered by a battery or by CT induction, and transmits wireless data via LoRa, Zigbee, or radio frequency. The sensor size is no larger than 30mm × 15mm and is encapsulated in high-temperature resistant epoxy resin.

[0009] 3. The automatic detection and protection device for contact temperature of large drawer-type circuit breakers according to claim 1, characterized in that the data acquisition and processing host includes a microprocessor, a wireless receiving unit, a data storage unit, and an ambient temperature compensation unit; The microprocessor has a built-in multi-level temperature judgment algorithm, a wireless receiving unit for receiving temperature data from various sensors, a data storage unit for storing historical temperature curves and event records, and an environmental temperature compensation unit for collecting the ambient temperature inside the cabinet for temperature compensation calculation.

[0010] Preferably, the warning and tripping control module includes an audible and visual alarm unit and a tripping control relay; the audible and visual alarm unit includes an LED indicator and a buzzer for tiered warning indication; The normally open contact of the trip control relay is connected in series to the original shunt trip coil circuit of the circuit breaker, and the relay coil is controlled by the output port of the data acquisition and processing host.

[0011] Preferably, the status indication and communication module includes a local human-machine interface and a remote communication interface; The local human-machine interface includes an LCD screen and operation buttons for displaying real-time temperature and parameter settings; the remote communication interface includes RS485, Ethernet or wireless communication interfaces, supporting Modbus-RTU and Modbus-TCP standard communication protocols.

[0012] Preferably, the multi-level temperature judgment logic of the data acquisition and processing host includes: Sensor fault detection, early warning threshold judgment, tripping threshold judgment, phase-to-phase temperature difference judgment, and temperature rise rate judgment; Sensor fault detection includes signal loss detection and battery undervoltage detection.

[0013] Preferably, the phase-to-phase temperature difference determination is to calculate the maximum temperature difference between the three phase contacts. When the maximum temperature difference exceeds the set temperature difference limit, the trip protection is triggered even if the absolute tripping temperature threshold is not reached. The temperature rise rate is determined by calculating the slope of temperature rise per unit time. When the temperature rise rate exceeds the set rate limit, an early warning or tripping is triggered.

[0014] An automatic detection and protection method for the contact temperature of large drawer-type circuit breakers includes the following steps: Step S1: System initialization, configure temperature warning threshold Temperature tripping threshold Maximum interphase temperature difference limit Maximum rate of temperature rise limit ; Step S2: Each wireless temperature sensor periodically collects the temperature data of the corresponding contact and wirelessly transmits it to the data acquisition and processing host. The sampling period of the wireless temperature sensor is configurable, ranging from 1 second to 60 seconds. The sensor adopts a low power consumption design, and its service life in battery-powered mode is no less than 5 years. Step S3: The data acquisition and processing host receives temperature data, reads the ambient temperature for compensation and correction, and adjusts the data according to the ambient temperature inside the cabinet. Temperature of each contact was measured. The correction is performed using the following formula:

[0015] This is the actual contact temperature after ambient temperature compensation; The contact temperature is directly measured by a wireless temperature sensor. This is the temperature compensation coefficient; The ambient temperature inside the switchgear is collected by the built-in environmental sensor of the data acquisition and processing host. Step S4: Perform sensor fault detection to determine if there is signal loss or low battery voltage. If so, trigger a fault alarm. Step S5: Determine whether the highest temperature exceeds the warning threshold. If so, an alert will be triggered, and the alert method is as follows: The system illuminates the warning indicator light, emits an intermittent alarm sound, and uploads the warning signal to the background monitoring system via the communication interface. During the early warning state, the system continues to monitor temperature changes, providing maintenance personnel with a window of opportunity to intervene. Step S6: Determine if the tripping condition is met: The highest temperature exceeds the tripping threshold. or the maximum interphase temperature difference exceeds or the rate of temperature rise exceeds If any condition is met, a trip command will be triggered. The temperature rise rate is calculated as follows:

[0016] in The current temperature. for Temperature before time For the calculation time window; Step S7: The trip control relay operates, driving the circuit breaker shunt trip coil to be energized, and the circuit breaker trips; Step S8: Record and upload relevant data of the tripping event, including time, location, and temperature curve.

[0017] Compared with the prior art, the beneficial effects of the present invention are: This invention enables 24 / 7 uninterrupted online temperature monitoring of critical contacts of circuit breakers, completely replacing the traditional manual inspection mode, eliminating the monitoring blind spots and safety risks of manual inspection, and ensuring that any temperature anomalies can be detected in a timely manner.

[0018] This invention innovatively adopts a multi-level temperature judgment logic that combines absolute temperature, interphase temperature difference, and temperature rise rate. It can not only detect steady-state over-temperature, but also identify potential contact problems through temperature difference analysis and capture sudden faults through temperature rise rate, truly realizing the transformation from "post-event remediation" to "pre-event prevention".

[0019] This invention can automatically trigger the circuit breaker trip protection within milliseconds when a dangerous temperature is detected, with a response speed far faster than manual intervention, effectively preventing the accident from escalating. Protection is achieved using the standard shunt trip interface of the circuit breaker, without requiring modifications to the main structure of the circuit breaker.

[0020] This invention employs a miniaturized wireless temperature sensor, eliminating the need for wiring and not interfering with drawer insertion / removal operations, making it suitable for the unique structure of drawer-type circuit breakers. The standardized tripping interface design is compatible with most mainstream brands of drawer-type circuit breakers on the market, simplifying on-site installation and modification without affecting the performance of existing equipment.

[0021] This invention provides a complete temperature data chain and event logging function, supports remote centralized monitoring, provides key data support for predictive maintenance and digital management of power distribution systems, and helps build smart power distribution systems. Attached Figure Description

[0022] Figure 1 This is a block diagram of the overall architecture of the large drawer-type circuit breaker contact temperature automatic detection and protection device of the present invention; Figure 2 This is a flowchart of the multi-level judgment logic of the protection method of this invention; Figure 3 This is a parameter diagram of the circuit breaker of the present invention; Figure 4 This is a diagram of the circuit breaker contacts of the present invention; Figure 5 This is a diagram of the wiring terminals of the present invention; Figure 6 This is a diagram illustrating the electric shock protection of the outer casing of this invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1-6 As shown, the present invention is an automatic detection and protection device for the contact temperature of a large drawer-type circuit breaker, comprising: a wireless temperature sensing module, a data acquisition and processing host, an early warning and tripping control module, and a status indication and communication module; The wireless temperature sensing module is installed at the upper and lower contacts of each phase inside the circuit breaker drawer to collect real-time temperature data of each contact and transmit it wirelessly. The wireless temperature sensing module includes multiple miniature wireless temperature sensors, which are installed at the upper and lower contacts of phases A, B, and C, respectively. The collected temperature data is transmitted wirelessly to the data acquisition and processing host located in the instrument room of the drawer. Each sensor is powered by a battery or by CT induction and transmits data wirelessly via LoRa, Zigbee, or radio frequency. The sensor size is no larger than 30mm × 15mm and is encapsulated in high-temperature resistant epoxy resin.

[0025] The data acquisition and processing host receives temperature data from various wireless temperature sensors, executes multi-level temperature judgment logic, and performs comprehensive analysis and decision-making based on absolute temperature thresholds, interphase temperature differences, and temperature rise rates. The host includes a microprocessor, a wireless receiving unit, a data storage unit, and an ambient temperature compensation unit. The microprocessor incorporates a multi-level temperature judgment algorithm. The wireless receiving unit receives temperature data from various sensors. The data storage unit stores historical temperature curves and event records. The ambient temperature compensation unit collects the ambient temperature inside the cabinet for temperature compensation calculations. The multi-level temperature judgment logic of the host includes: sensor fault detection, warning threshold judgment, tripping threshold judgment, interphase temperature difference judgment, and temperature rise rate judgment. Sensor fault detection includes signal loss detection and battery undervoltage detection. Interphase temperature difference judgment calculates the maximum temperature difference between the three-phase contacts. When the maximum temperature difference exceeds the set temperature difference limit, tripping protection is triggered even if the absolute tripping temperature threshold is not reached. Temperature rise rate judgment calculates the temperature rise slope per unit time. When the temperature rise rate exceeds the set rate limit, a warning or tripping is triggered.

[0026] The drawer-type circuit breaker achieves electrical connection with the busbar system through upper and lower insertion contacts. A miniature wireless temperature sensor is fixedly installed on the contact arm of each phase using a binding or clip-on method. The sensor's temperature-sensing surface is in close contact with the contact conductor surface to ensure good thermal contact. The sensor's installation position avoids the insertion and removal trajectory, so as not to affect the normal pushing in and pulling out operation of the drawer. The sensors for phases A, B, and C are each assigned different network addresses for easy identification and differentiation by the data acquisition and processing host.

[0027] The early warning and trip control module is used to drive local audible and visual alarms based on the decision results of the data acquisition and processing host, and to connect to the circuit breaker's shunt trip coil circuit through the control relay contacts to achieve automatic trip protection. The early warning and trip control module includes an audible and visual alarm unit and a trip control relay. The audible and visual alarm unit includes LED indicator lights and a buzzer for graded early warning indication. The normally open contact of the trip control relay is connected in series to the circuit breaker's original shunt trip coil circuit, and the relay coil is controlled by the output port of the data acquisition and processing host.

[0028] The status indication and communication module is used to provide local status display and upload temperature data, alarm information, and tripping events to the background monitoring system. The status indication and communication module includes a local human-machine interface and a remote communication interface. The local human-machine interface includes an LCD screen and operation buttons to display real-time temperature and parameter settings. The remote communication interface includes RS485, Ethernet, or wireless communication interfaces, supporting Modbus-RTU and Modbus-TCP standard communication protocols.

[0029] One end of the shunt trip coil (MX) of the circuit breaker body is connected to the positive terminal (L+) of the external control power supply, and the other end is led to the secondary terminal block of the circuit breaker. The normally open contact of the trip control relay (KR) of the present invention is connected in series in this circuit. The trip command output port (OUT) of the data acquisition and processing host (5) is connected to one end of the coil of the relay (KR) through a current limiting resistor, and the other end of the coil is connected to the negative terminal (L-) of the control power supply. Under normal operating conditions, the OUT port outputs a low level, the relay (KR) coil is de-energized, the normally open contact is opened, the shunt trip coil (MX) is not energized, and the circuit breaker operates normally. When the host determines that tripping is required, the OUT port outputs a high level, the relay (KR) coil is energized, the normally open contact is closed, the shunt trip coil (MX) is energized, and an electromagnetic attraction is generated to drive the circuit breaker tripping mechanism to act, the circuit breaker trips immediately, and the main circuit current is cut off.

[0030] Combination Figure 2 As shown, the automatic detection and protection method for contact temperature of large drawer-type circuit breakers of the present invention is characterized by comprising the following steps: Step S1: After the system is powered on, the initialization program is executed first. The microprocessor loads the default operating parameters or user-configured parameters and configures the temperature warning threshold. Temperature tripping threshold Maximum interphase temperature difference limit Maximum rate of temperature rise limit After initialization, the system enters normal operating mode; Step S2: The wireless receiving unit of the data acquisition and processing host continuously monitors the wireless channel. After receiving the sensor data packets, it performs verification and decoding to obtain the temperature values ​​of each contact. At the same time, the host collects the ambient temperature inside the cabinet through the built-in ambient temperature sensor and wirelessly sends it to the data acquisition and processing module. Step S3: The data acquisition and processing module receives temperature data, reads the ambient temperature for compensation and correction, and adjusts the data according to the ambient temperature inside the cabinet. Temperature of each contact was measured. The correction is performed using the following formula:

[0031] This is the actual contact temperature after ambient temperature compensation; The contact temperature is directly measured by a wireless temperature sensor. This is the temperature compensation coefficient; The ambient temperature inside the switchgear is collected by the built-in environmental sensor in the data acquisition and processing module. Step S4: Perform sensor fault detection. The host checks whether each sensor reports data within the specified time. If a sensor fails to report for three consecutive cycles (30 seconds), it is determined to be a signal loss fault. Simultaneously, check the battery voltage reported by the sensor; if it is below 2.5V, it is determined to be a low battery voltage. If any fault exists, proceed to step S5, illuminate the fault indicator light, and upload the fault code. If no fault exists, continue execution. Step S5: Determine whether the highest temperature exceeds the warning threshold. If so, an early warning will be activated; the host will iterate through the compensated temperatures of the measuring points to find the highest temperature. If the highest temperature is ≥85℃, then step S6 will be executed to activate the early warning program: the yellow warning indicator light will illuminate, the buzzer will emit an intermittent "beep-beep-" alarm sound, and an early warning message will be sent to the background. During the early warning period, the system will continue to monitor the temperature. If the highest temperature drops below 80℃ within 60 seconds, the early warning will be automatically lifted. Step S6: Determine if the tripping condition is met: The highest temperature exceeds the tripping threshold. or the maximum interphase temperature difference exceeds or the rate of temperature rise exceeds If any of the conditions is met, a trip command will be triggered. The calculation of the temperature rise rate is as follows:

[0032] in The current temperature. for Temperature before time For the calculation time window; The host performs three checks simultaneously: Absolute temperature determination: Is the highest temperature ≥105℃? Interphase temperature difference judgment: Calculate the maximum temperature difference between the upper contacts of the three phases and the maximum temperature difference between the lower contacts of the three phases, and determine whether it is ≥30℃; Temperature rise rate judgment: Calculate the temperature rise rate at each measuring point using a 5-minute sliding window, and check if it is ≥5℃ / min.

[0033] If any one of the three conditions is met, immediately execute step 109 to issue a tripping command. Step S7: The trip control relay operates, driving the circuit breaker shunt trip coil to be energized, and the circuit breaker trips; the main unit output port OUT is set to high level, the trip relay KR is energized and closes its normally open contact, the circuit breaker shunt trip coil MX is energized, the circuit breaker completes tripping within 100ms, and the main circuit is de-energized. Step S8: Record and upload relevant data of the tripping event, including time, location, and temperature curve; the system automatically records the tripping time, fault phase, temperature of each measuring point at the time of tripping, temperature curve of the past 30 minutes, etc., generates an event record and actively uploads it to the background monitoring system, and locks the tripped state. Normal operation can only be restored after manual reset.

[0034] Example 1:

[0035] This implementation uses a large drawer-type circuit breaker of a certain brand with a rated current of 2000A used in a data center as an example. Battery-powered wireless temperature sensors are installed at the top and bottom of six main contacts on phases A, B, and C. System parameter settings: =90℃, =115℃, =35℃, =6℃ / min, intervention time window 120 seconds.

[0036] During operation, the lower contact of phase B experienced insufficient contact pressure and a gradual increase in contact resistance due to improper insertion during installation. The system monitored a rapid increase in the temperature of the lower contact of phase B from 72℃ to 112℃ within 15 minutes. At this time: When the temperature reaches 90℃, the system first issues an early warning signal, and the background monitoring pop-up window displays the warning. When the temperature rises to 112℃, although it does not reach the absolute tripping threshold of 115℃, the temperature difference between the lower contact of phase B and the lower contact of phase A (73℃) has reached 39℃, exceeding the temperature difference limit of 35℃. The system immediately triggered a trip command, causing the circuit breaker to trip and successfully preventing contact welding and potential electrical fire accidents.

[0037] The backend system accurately records the entire temperature change process and tripping events, providing a complete data chain for maintenance personnel to analyze faults.

[0038] Example 2:

[0039] In an industrial plant, the silver plating on the C-phase contacts of a 1600A drawer-type circuit breaker was worn due to long-term arc erosion, resulting in increased contact resistance. During a single equipment startup, the inrush current caused the contact temperature to surge from 65°C to 98°C within 3 minutes, a temperature rise rate of 11°C / min. The system detected a temperature rise rate far exceeding the limit of 6°C / min. Although the absolute temperature of 98°C had not yet reached the 115°C tripping threshold, the system still directly triggered the trip protection, promptly cutting off the power supply and effectively preventing contact overheating damage.

[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An automatic detection and protection device for the contact temperature of a large drawer-type circuit breaker, characterized in that, include: The wireless temperature sensing module is used to be installed at the upper and lower contacts of each phase inside the circuit breaker drawer to collect real-time temperature data of each contact and transmit it wirelessly. The data acquisition and processing host is used to receive temperature data sent by various wireless temperature sensors, execute multi-level temperature judgment logic, and make comprehensive analysis and decisions by combining absolute temperature threshold, phase-to-phase temperature difference and temperature rise rate. The early warning and trip control module is used to drive the local audible and visual alarm based on the decision results of the data acquisition and processing host, and to connect to the circuit breaker shunt trip coil circuit through the control relay contacts to achieve automatic trip protection; The status indication and communication module is used to provide local status display and upload temperature data, alarm information, and tripping events to the background monitoring system.

2. The automatic detection and protection device for contact temperature of a large drawer-type circuit breaker according to claim 1, characterized in that, The wireless temperature sensing module includes multiple miniature wireless temperature sensors, which are installed at the upper and lower contacts of phases A, B, and C, respectively. Each sensor is powered by a battery or by CT induction and transmits data wirelessly via LoRa, Zigbee, or radio frequency. The sensor size is no larger than 30mm × 15mm and is encapsulated in high-temperature resistant epoxy resin.

3. The automatic detection and protection device for contact temperature of a large drawer-type circuit breaker according to claim 1, characterized in that, The data acquisition and processing host includes a microprocessor, a wireless receiving unit, a data storage unit, and an ambient temperature compensation unit. The microprocessor has a built-in multi-level temperature judgment algorithm, a wireless receiving unit for receiving temperature data from various sensors, a data storage unit for storing historical temperature curves and event records, and an environmental temperature compensation unit for collecting the ambient temperature inside the cabinet for temperature compensation calculation.

4. The automatic detection and protection device for contact temperature of a large drawer-type circuit breaker according to claim 1, characterized in that, The warning and tripping control module includes an audible and visual alarm unit and a tripping control relay; the audible and visual alarm unit includes an LED indicator and a buzzer for graded warning indication. The normally open contact of the trip control relay is connected in series to the original shunt trip coil circuit of the circuit breaker, and the relay coil is controlled by the output port of the data acquisition and processing host.

5. The automatic detection and protection device for contact temperature of a large drawer-type circuit breaker according to claim 1, characterized in that, The status indication and communication module includes a local human-machine interface and a remote communication interface; The local human-machine interface includes an LCD screen and operation buttons for displaying real-time temperature and parameter settings; the remote communication interface includes RS485, Ethernet or wireless communication interfaces, supporting Modbus-RTU and Modbus-TCP standard communication protocols.

6. The automatic detection and protection device for contact temperature of a large drawer-type circuit breaker according to claim 3, characterized in that, The multi-level temperature judgment logic of the data acquisition and processing host includes: Sensor fault detection, early warning threshold judgment, tripping threshold judgment, phase-to-phase temperature difference judgment, and temperature rise rate judgment; Sensor fault detection includes signal loss detection and battery undervoltage detection.

7. The automatic detection and protection device for contact temperature of a large drawer-type circuit breaker according to claim 6, characterized in that, The phase-to-phase temperature difference determination is to calculate the maximum temperature difference between the three phase contacts. When the maximum temperature difference exceeds the set temperature difference limit, the trip protection is triggered even if the absolute tripping temperature threshold is not reached. The temperature rise rate is determined by calculating the slope of temperature rise per unit time. When the temperature rise rate exceeds the set rate limit, an early warning or tripping is triggered.

8. The protection method of the automatic detection and protection device for contact temperature of large drawer-type circuit breakers according to any one of claims 1-7, characterized in that, Includes the following steps: Step S1: System initialization, configure temperature warning threshold Temperature tripping threshold Maximum interphase temperature difference limit Maximum rate of temperature rise limit ; Step S2: Each wireless temperature sensor periodically collects the temperature data of the corresponding contact and wirelessly transmits it to the data acquisition and processing host. Step S3: The data acquisition and processing host receives temperature data, reads the ambient temperature for compensation and correction, and adjusts the data according to the ambient temperature inside the cabinet. Temperature of each contact was measured. The correction is performed using the following formula: This is the actual contact temperature after ambient temperature compensation; The contact temperature is directly measured by a wireless temperature sensor. This is the temperature compensation coefficient; The ambient temperature inside the switchgear is collected by the built-in environmental sensor of the data acquisition and processing host. Step S4: Perform sensor fault detection to determine if there is signal loss or low battery voltage. If so, trigger a fault alarm. Step S5: Determine whether the highest temperature exceeds the warning threshold. If so, an alert will be triggered; Step S6: Determine if the tripping conditions are met: The highest temperature exceeds the tripping threshold. or the maximum interphase temperature difference exceeds or the rate of temperature rise exceeds If any of the conditions is met, a trip command will be triggered. The calculation of the temperature rise rate is as follows: in The current temperature. for Temperature before time For the calculation of the time window; Step S7: The trip control relay operates, driving the circuit breaker shunt trip coil to be energized, and the circuit breaker trips; Step S8: Record and upload relevant data of the tripping event, including time, location, and temperature curve.

9. The automatic detection and protection method for contact temperature of a large drawer-type circuit breaker according to claim 8, characterized in that, The warning in step S5 includes: The system illuminates the warning indicator light, emits an intermittent alarm sound, and uploads the warning signal to the background monitoring system via the communication interface. During the early warning state, the system continues to monitor temperature changes, providing maintenance personnel with a window of opportunity to intervene.

Images