Terminal grading early warning control device and early warning judgment method

Abstract

The invention relates to the technical field of temperature early warning, in particular to a terminal grading early warning control device and an early warning judgment method. The line crimping head standard component is used for connecting a low-voltage wiring terminal, the surface is provided with a temperature-sensing color-changing material, and when the temperature reaches a preset threshold value, irreversible color change is generated to provide visual prompt. The temperature sensor is installed on a low-voltage wiring terminal and is connected to the temperature early warning control module, and real-time temperature signals are collected and transmitted. The temperature early warning control module carries out control judgment according to the collected signals, and the temperature sound-light alarm module is connected with the temperature early warning control module and provides over-temperature alarm according to a control instruction. According to the invention, closed-loop prevention and control of passive color change and active grading intervention of heating of the wiring terminal are realized for the first time; cost is low, and the blank of fire early warning of a common low-voltage power distribution system can be effectively filled; the method is convenient to construct, greatly reduces the false alarm rate, supports remote batch management, and is especially suitable for distributed power distribution scenes.

Description

Technical Field

[0001] This invention relates to the field of temperature early warning technology, and in particular to a terminal block graded early warning control device and early warning judgment method. Background Technology

[0002] With the continuous expansion of low-voltage power distribution systems, low-voltage circuit breakers, electricity meters, terminal blocks, and other wiring terminals are operating under high loads for extended periods. Due to factors such as improper construction practices, aging equipment, humid environments, and rodent infestation, the contact resistance of these terminals increases, making them highly susceptible to abnormal overheating under continuous high current. Statistical data shows that overheating of electrical connections is one of the leading causes of low-voltage electrical fires, accounting for over 30% of all electrical fires.

[0003] In existing technologies, the monitoring and protection against overheating of wiring terminals mainly involve the following methods: traditional infrared thermometers or handheld thermal imagers are used for periodic inspections, relying on manual labor, resulting in low inspection frequency, high missed detection rates, and inability to detect hidden heat points in real time; ordinary temperature sensors + PLCs only provide over-temperature audible and visual alarm functions, lacking tiered early warning and active power-off protection mechanisms; intelligent circuit breakers or electronic overload protectors are expensive and only target the circuit breaker body, failing to cover all heat-prone points such as electricity meter wiring terminals and terminal blocks; thermal color-changing labels or thermal paint are used, but these solutions only provide passive visual prompts and cannot achieve automatic alarms.

[0004] Therefore, there is a need for a terminal block-based hierarchical early warning control device and early warning judgment method that can achieve a closed-loop prevention and control system of "passive color change + active hierarchical intervention", effectively filling the gap in early warning of fires in ordinary low-voltage power distribution systems. This device only requires replacing standard crimp connectors and attaching sensors, without modifying the original wiring, making construction convenient and significantly reducing the false alarm rate to meet the needs of the current environment. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is that: manual inspections are infrequent, have a high rate of missed inspections, and cannot detect hidden heat points in real time; smart circuit breakers or electronic overload protectors are expensive and only target the circuit breaker body, which cannot cover all heat-prone points such as the wiring terminals and terminal blocks of the electricity meter; and thermal color-changing labels or thermal paint can only provide passive visual prompts and cannot achieve automatic alarms.

[0006] The above-mentioned technical problems are solved by the following technical solution: This invention proposes a terminal block hierarchical early warning control device, which includes, Standard components for line crimp connectors, temperature sensors, temperature audible and visual alarm modules, and temperature early warning control modules; Standard crimp connectors are used to connect low-voltage terminals and have a surface coating of temperature-sensitive color-changing material. When the temperature reaches a preset threshold, an irreversible color change occurs to provide a visual alert; the temperature sensor is installed on the low-voltage terminal block and connected to the temperature early warning control module to collect and transmit real-time temperature signals. The temperature warning control module makes control judgments based on the collected signals, and the temperature audible and visual alarm module is connected to the temperature warning control module to provide over-temperature alarms according to control commands.

[0007] In a preferred embodiment of the terminal block hierarchical early warning control device of the present invention: The temperature warning and control unit includes an MCU control circuit, a temperature acquisition circuit, a warning output contact circuit, a trip output contact circuit, and a system power supply circuit; The temperature acquisition circuit supports multiple signal inputs, connects to temperature sensors, and transmits the processed voltage signals to the conversion interface of the MCU control circuit. The warning output contact circuit and the trip output contact circuit are connected to the pins of the MCU control circuit through relays to realize the output control of alarm and trip signals; The system power supply circuit is connected to the MCU core to provide backup power support.

[0008] In a preferred embodiment of the terminal block hierarchical early warning control device of the present invention: The temperature sensor includes an NTC sensing unit; The NTC sensing unit is connected to the corresponding TEMP pin of the temperature acquisition circuit and grounded together to form a cascaded acquisition architecture.

[0009] In a preferred embodiment of the terminal block hierarchical early warning control device of the present invention: The temperature warning control unit includes a 4G communication module circuit for data uploading and remote settings; The 4G communication module connects to the MCU control circuit through the RXD and TXD pins of the USART serial port to achieve data interaction, and accesses the 4G network through the antenna interface to upload temperature signals.

[0010] In a preferred embodiment of the terminal block hierarchical early warning control device of the present invention: The MCU control circuit converts the input temperature signal through the ADC conversion interface and executes control logic according to the preset threshold. The multi-channel input of the ADC conversion interface is connected to the temperature acquisition circuit to realize a closed control loop for the early warning output contact and the trip output contact. A method for early warning judgment includes the aforementioned terminal block hierarchical early warning control device, and includes the following steps: S1. Initialize the temperature warning control unit, establish a communication link, and configure the first-level warning threshold, the second-level warning threshold, the temperature sampling frequency, and the number of multiple monitoring channels; S2. The temperature signal of the terminal block is collected in real time by a temperature sensor and the continuous temperature change is monitored. S3. Preprocess the acquired temperature signal, process the analog voltage signal through the ADC conversion interface in the MCU control circuit, and perform subsequent analysis. S4. Based on the pre-processed temperature signal, a graded early warning judgment is made. When any temperature reaches the first-level early warning threshold, the early warning output contact circuit is activated and the temperature sound and light alarm module is started. S5. After an early warning or trip, continuously monitor the temperature recovery and resample the temperature. If the temperature of all circuits drops to a safe range, automatically reset the temperature audible and visual alarm module.

[0011] In a preferred embodiment of the early warning judgment method described in this invention: In the S2~3 process, the temperature signal of the terminal is collected by the NTC sensing unit and then sampled and converted by the ADC conversion interface of the MCU control circuit. The ADC conversion interface converts the voltage value into the corresponding temperature value, and collects the signals from TEMP1 to TEMP14 channels and stores them as an array.

[0012] In a preferred embodiment of the early warning judgment method described in this invention: In the S4 process, a preset time A and a threshold increment B are set; If the temperature exceeds the threshold increase B within a preset time A, the color change state of the temperature-sensitive color-changing material will be used to provide on-site visual prompts to help confirm the severity of the overheating. Based on the severity, prioritize processing the signal with the highest temperature or the fastest rise rate among the multiple signals.

[0013] In a preferred embodiment of the early warning judgment method described in this invention: In the S4 process, after the audible and visual alarm module is activated, a secondary threshold C is set and temperature changes are continuously monitored. If the temperature continues to rise beyond the secondary threshold C after the alarm, a trip operation is performed, and the air switch is opened by the relay activating the trip output contact circuit.

[0014] The beneficial effects of this invention are as follows: it achieves a closed-loop prevention and control system of "passive color change + active hierarchical intervention" for the first time to detect the heating of the wiring terminals, which improves the fire prevention and control capability by an order of magnitude compared with the traditional solution; it has low cost and can effectively fill the gap in early fire warning of ordinary low-voltage power distribution systems; it does not require modification of the original wiring, is easy to construct, significantly reduces the false alarm rate, supports remote batch management, and is particularly suitable for distributed power distribution scenarios such as chain supermarkets, rental apartments, renovation of old residential areas, and new energy charging stations. Attached Figure Description

[0015] 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. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0016] Figure 1 A hardware connection framework diagram of the control system of the present invention is shown.

[0017] Figure 2 The diagram shows the frame connection of the temperature early warning control module of the present invention.

[0018] Figure 3 The circuit diagram of the temperature acquisition circuit of the present invention is shown.

[0019] Figure 4 The circuit diagram of the MCU control circuit of the present invention is shown.

[0020] Figure 5 The circuit diagram of the trip output contact circuit of the present invention is shown.

[0021] Figure 6 The circuit diagram of the trip output contact circuit of the present invention is shown.

[0022] Figure 7 The schematic diagram of the 220V to 12V power supply circuit of the system of the present invention is shown.

[0023] Figure 8 The circuit diagram of the 12V to 5V power supply circuit of the present invention is shown. Figure 9 The circuit diagram of the 5V to 3.3V power supply circuit of the present invention is shown.

[0024] Figure 10 The circuit diagram of the 2.5V reference of the power supply circuit of the system of the present invention is shown. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0026] The terminology used in this invention refers to those general terms currently widely used in the art in consideration of the functionality of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new techniques. Furthermore, specific terms may be chosen independently, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terminology used in this specification should not be construed as simple names, but rather based on the meaning of the terms and the overall description of the invention.

[0027] Reference Figures 1-2 This embodiment provides a terminal block hierarchical early warning control device.

[0028] The device in this embodiment mainly includes a standard crimp connector 1, a temperature sensor 2, a temperature audible and visual alarm module 3, and a temperature early warning control module 4.

[0029] The aforementioned components are interconnected through standardized interfaces to form a compact, low-cost integrated system that is easy to install in existing low-voltage distribution boxes. The standard line crimp connector 1 serves as the mechanical connection component of the device, directly replacing the crimp connectors of the original wiring terminals for seamless integration. The temperature sensor 2 is fixed to or near the wiring terminal surface and connected to the temperature warning control module 4 via a signal line. The temperature audible and visual alarm module 3 is connected to the temperature warning control module 4 via a control line, receiving digital or analog commands. The temperature warning control module 4, as the core processor, integrates signal acquisition, logic judgment, and output control functions.

[0030] Line crimp connector standard part 1 is used to connect low-voltage terminals and fix wires at the inlet and outlet ports of low-voltage circuit breakers or electricity meters. Line crimp connector standard part 1 is made of copper or aluminum alloy and its surface is uniformly coated with a new type of temperature-sensitive color-changing material with a thickness controlled between 0.05-0.1mm to ensure that it does not affect electrical conductivity.

[0031] When the temperature of the terminal block rises continuously due to increased contact resistance or high current load, reaching a preset threshold, the temperature-sensitive color-changing material undergoes a chemical or physical phase change, producing an irreversible color change. This change is independent of external power supply and is a passive indication mechanism, providing permanent visual cues for maintenance personnel even during system power outages or fault conditions. In practical applications, if the terminal block becomes loose due to insufficient installation torque, its temperature will gradually rise to the threshold after long-term operation, causing the crimped connector surface to permanently turn red, reminding users or inspection personnel to promptly inspect or replace it, preventing the accumulation of potential hazards.

[0032] Temperature sensor 2 is mounted on the low-voltage terminal block for real-time temperature signal acquisition. The sensor probe is fixed to the metal surface of the terminal block or near the crimp connector using thermally conductive adhesive or a clamp to ensure high heat transfer efficiency. This embodiment uses an NTC negative temperature coefficient thermistor sensor, whose resistance decreases as temperature increases.

[0033] The sensor is connected to the temperature warning control module 4 via a double-core shielded cable, transmitting an analog voltage signal. In the circuit, the sensor is connected in series with a fixed resistor to form a voltage divider network. After the 3.3V power supply is divided by the fixed resistor and the NTC sensor, a voltage that varies with temperature is generated at the voltage divider point. The voltage signal is directly transmitted to the ADC input port of the control module.

[0034] The temperature warning control module 4 makes control decisions based on the collected temperature signals. The temperature warning control module 4 is implemented using a low-power microcontroller and integrates an ADC converter, GPIO output pins, and corresponding basic logic circuits.

[0035] First, the temperature warning control module 4 digitizes the analog voltage signal from the temperature sensor 2 via ADC conversion, and then performs threshold comparison and judgment: preset first-level warning threshold and second-level warning threshold. If the calculated temperature exceeds the first-level threshold, a high-level signal is output to activate the temperature audible and visual alarm module 3; if the measured temperature further exceeds the second-level threshold, a trip signal is output.

[0036] As one embodiment provided, such as Figures 1-5 , The temperature warning control unit 4, as the core component of the device, is responsible for the acquisition, processing, judgment, and output execution of temperature signals. Specifically, the temperature warning control unit 4 includes an MCU control circuit 41, a temperature acquisition circuit 42, a warning output contact circuit 43, a trip output contact circuit 44, and a system power supply circuit 45. These sub-circuits are integrated via a PCB board and support DIN rail or screw mounting. In this solution, the MCU control circuit 41 uses an STM32F103 series microcontroller as the core processor.

[0037] The temperature acquisition circuit 42 supports multiple signal inputs, connects to the temperature sensor 2, and transmits the processed voltage signal to the conversion interface of the MCU control circuit 41. The circuit board has 14 TEMP pins and one common GND pin, forming a multi-parallel input architecture. Each TEMP pin is connected to a 3.3V power supply through a fixed resistor, forming a resistor divider network with the NTC sensing unit 21 of the external temperature sensor 2.

[0038] When the temperature changes, the NTC resistance decreases, and the voltage at the voltage divider point changes accordingly. After high-frequency noise is filtered out by a 0.1μF filter capacitor, the signal is directly transmitted to the ADC conversion interface 411 of the MCU control circuit 41. The MCU control circuit 41 supports at least 14 cascaded acquisition channels, achieving efficient data transmission and avoiding excessive CPU resource consumption. In practical applications, the multi-channel design allows for simultaneous monitoring of multiple terminals, facilitating comprehensive coverage of heat-prone areas.

[0039] Temperature sensor 2 includes an NTC sensing unit 21, which is a thermistor. The NTC sensing unit 21 is connected to the corresponding TEMP pin of the temperature acquisition circuit 42 and grounded to GND, forming a cascaded acquisition architecture. The positive terminal of each NTC sensing unit 21 is connected to the TEMP pin, and the negative terminal is grounded, forming an independent voltage divider branch, but sharing power and ground. This cascaded structure simplifies wiring and supports hot-swapping. During installation, the sensing unit is fixed to the terminal block surface and thermally conductive silicone is used to ensure tight thermal coupling.

[0040] The warning output contact circuit 43 and the trip output contact circuit 44 are connected to the pins of the MCU control circuit 41 via relays to realize the output control of alarm and trip signals. When the MCU control circuit 41 detects an abnormal temperature, it drives the relay to close the normally open contact. The warning output contact circuit 43 is connected to the temperature audible and visual alarm module 3, and the alarm is activated when it is closed; the trip output contact circuit 44 is connected to the low-voltage air switch, and the trip will be triggered when it is closed to cut off the power supply. The entire design also provides electrical isolation to ensure safety.

[0041] The system power supply circuit 45 is connected to the MCU control circuit 41, providing backup power support. The temperature warning control unit 4 also includes a 4G communication module circuit 46 for data upload and remote settings. The 4G communication module circuit 46 integrates a SIM card slot and an antenna interface, and is connected to the MCU control circuit 41 via the RXD and TXD pins of the USART serial port to achieve data interaction. The MCU control circuit 41 converts the input temperature signal through the ADC conversion interface 411 and executes control logic according to a preset threshold. The multi-channel input of the ADC conversion interface 411 is connected to the temperature acquisition circuit 42.

[0042] Temperature sensor 2 collects signals and transmits them to temperature acquisition circuit 42, where MCU control circuit 41 processes and judges the data. In case of an anomaly, it will activate warning output contact circuit 43 and trip output contact circuit 44, and upload data via 4G communication module 46. System power supply circuit 45 ensures the reliability of the entire device's power supply. Through this architecture, this device achieves multi-channel integrated monitoring.

[0043] As one embodiment provided, such as Figures 1-7 , The method in this embodiment realizes closed-loop control of "monitoring-judgment-intervention-recovery", which significantly improves the intelligence and reliability of the system.

[0044] In step S1, the temperature warning control unit needs to be initialized, a communication link established, and the first-level warning threshold, second-level warning threshold, temperature sampling frequency, and number of multi-channel monitoring are configured. After the system is powered on, the MCU control circuit 41 executes a self-test program to check the ADC conversion interface 411, relay status, and power supply voltage. Then, a TCP connection is established with the 4G communication module circuit 46 via the USART serial port to verify the cloud server communication link. The complete set of configuration parameters includes the first-level warning threshold, second-level warning threshold, temperature sampling frequency, and number of multi-channel monitoring. These parameters are stored in the MCU's EEPROM and support local button operation or remote APP operation.

[0045] In step S2, the temperature signal of the terminal block is acquired in real time by temperature sensor 2, and the continuous temperature change is monitored. The NTC sensing unit 21 of temperature sensor 2 is connected to the TEMP1 to TEMP14 pins of temperature acquisition circuit 42 to form a resistor voltage divider network and generate an analog voltage signal. MCU control circuit 41 acquires multiple signals in a polling manner through ADC conversion interface 411, sampling each channel 10 times and averaging the results to reduce noise.

[0046] Simultaneously, the system monitors continuous temperature changes, including calculating the rate of temperature rise and duration. The entire process supports a cascaded acquisition architecture, with all signals grounded to GND to ensure signal stability.

[0047] In step S3, the system preprocesses the acquired temperature signal and processes the analog voltage signal through the ADC conversion interface 411 in the MCU control circuit 41 for subsequent analysis. The ADC conversion interface 411 converts the analog voltage into a 12-bit digital value, which is then converted into a temperature value. The MCU control circuit 41 collects and stores the signals from TEMP1 to TEMP14.

[0048] In step S4, a graded early warning judgment is performed based on the pre-processed temperature signal. When any temperature reaches the first-level early warning threshold, the early warning output contact circuit 43 will be activated, and the temperature audible and visual alarm module 3 will be started. The current temperature value is compared with the first-level threshold. If any temperature exceeds the threshold, the temperature early warning control unit 4 outputs a high level, driving the relay of the early warning output contact circuit 43 to engage, and subsequently activating the temperature audible and visual alarm module 3 to emit flashing lights and an alarm sound.

[0049] A preset time A and a threshold increase B are set to monitor temperature trends. If the increase exceeds B within time A, a visual alert is provided on-site, taking into account the color change of the temperature-sensitive color-changing material on the standard crimp connector 1, to help confirm the severity of overheating. Based on the severity, the signal with the highest temperature or the fastest rising rate among the multiple signals is processed first.

[0050] After the audible and visual alarm module 3 is activated, it sets a secondary threshold C and continuously monitors temperature changes. If the temperature continues to rise beyond C after the alarm, it performs a trip operation and controls the air switch to open by activating the relay to close the trip output contact circuit 44.

[0051] In step S5, after an early warning or trip, the system will continuously monitor the temperature recovery and resample the temperature. If the temperature of all circuits drops to a safe range, the temperature audible and visual alarm module 3 will be automatically reset.

[0052] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A terminal block hierarchical early warning control device, characterized in that: include, Standard crimp connector (1), temperature sensor (2), temperature audible and visual alarm module (3), and temperature early warning control module (4); The standard crimp connector (1) is used to connect low-voltage terminals and has a temperature-sensitive color-changing material on its surface. When the temperature reaches a preset threshold, an irreversible color change occurs to provide a visual cues. The temperature sensor (2) is installed on the low-voltage terminal block and connected to the temperature early warning control module (4) to collect and transmit real-time temperature signals; The temperature warning control module (4) makes control judgments based on the collected signals. The temperature sound and light alarm module (3) is connected to the temperature warning control module (4) and provides over-temperature alarms according to the control instructions.

2. The terminal block hierarchical early warning control device according to claim 1, characterized in that: The temperature warning control unit (4) includes an MCU control circuit (41), a temperature acquisition circuit (42), a warning output contact circuit (43), a trip output contact circuit (44), and a system power supply circuit (45). The temperature acquisition circuit (42) supports multiple signal inputs, connects to the temperature sensor (2), and transmits the processed voltage signal to the conversion interface of the MCU control circuit (41). The warning output contact circuit (43) and the trip output contact circuit (43) are connected to the pins of the MCU control circuit (41) through relays to realize the output control of alarm and trip signals; The system power supply circuit (45) is connected to the MCU control circuit (41) to provide backup power support.

3. The terminal block hierarchical early warning control device according to claim 1, characterized in that: The temperature sensor (2) includes an NTC sensing unit (21); The NTC sensing unit (21) is connected to the corresponding TEMP pin of the temperature acquisition circuit (42) and grounded in a unified manner to form a cascaded acquisition architecture.

4. The terminal block hierarchical early warning control device according to any one of claims 1 to 3, characterized in that: The temperature warning control unit (4) includes a 4G communication module circuit (46) for data uploading and remote setting; The 4G communication module (46) is connected to the MCU control circuit (41) through the RXD and TXD pins of the USART serial port to realize data interaction, and accesses the 4G network through the antenna interface to upload the temperature signal.

5. The early warning judgment method according to claim 4, characterized in that: The MCU control circuit (41) converts the input temperature signal through the ADC conversion interface (411) and executes control logic according to the preset threshold. The multi-channel input of the ADC conversion interface (411) is connected to the temperature acquisition circuit (42) to realize the closed control loop of the early warning output contact and the trip output contact.

6. A method for early warning judgment, characterized in that: The device includes the terminal block hierarchical early warning control device as described in claim 5, and includes the following steps: S1. Initialize the temperature warning control unit, establish a communication link, and configure the first-level warning threshold, the second-level warning threshold, the temperature sampling frequency, and the number of multiple monitoring channels; S2. The temperature signal of the terminal block is collected in real time by the temperature sensor (2) and the continuous change of temperature is monitored. S3. The collected temperature signal is preprocessed and the analog voltage signal is processed through the ADC conversion interface (411) in the MCU control circuit (41) for subsequent analysis. S4. Based on the pre-processed temperature signal, a graded early warning judgment is made. When any temperature reaches the first-level early warning threshold, the early warning output contact circuit (43) is activated and the temperature sound and light alarm module (3) is started. S5. After an early warning or trip, continuously monitor the temperature recovery and resample the temperature. If the temperature of all circuits drops to a safe range, automatically reset the temperature audible and visual alarm module (3).

7. The early warning judgment method according to claim 6, characterized in that: In the S2~3 process, the terminal temperature signal is collected by the NTC sensing unit (21) and then multi-channel sampling conversion is performed through the ADC conversion interface (411) of the MCU control circuit (41). The ADC conversion interface (411) converts the voltage value into the corresponding temperature value, collects the signals from TEMP1 to TEMP14 in a unified manner, and stores them as an array.

8. The early warning judgment method according to claim 7, characterized in that: In the S4 process, a preset time A and a threshold increment B are set; If the temperature exceeds the threshold increase B within a preset time A, the color change state of the temperature-sensitive color-changing material will be used to provide on-site visual prompts to help confirm the severity of the overheating. Based on the severity, prioritize processing the signal with the highest temperature or the fastest rise rate among the multiple signals.

9. The early warning judgment method according to claim 8, characterized in that: In the S4 process, after the sound and light alarm module (3) is activated, it sets the secondary threshold C and continuously monitors the temperature change; If the temperature continues to rise beyond the secondary threshold C after the alarm, a trip operation is performed, and the air switch is opened by the relay energizing the trip output contact circuit (43).

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