Ring main unit cable elbow-shaped head temperature measuring device and early warning method thereof

Abstract

The invention belongs to the technical field of ring main unit cable joint temperature measurement, and relates to a ring main unit cable elbow-shaped head temperature measuring device and an early warning method thereof. The device comprises a single-chip microcomputer and a screw rod, wherein the single-chip microcomputer is electrically connected with a static memory, an environment temperature probe and a plug temperature probe; the plug temperature probe is embedded into the tail end of the screw rod, and the tail end of the screw rod is connected with the plug; the plug temperature probe measures the temperature of the plug installed in the cable elbow-shaped head, and the environment temperature probe measures the temperature of the environment around the cable elbow-shaped head. The single chip microcomputer firstly calculates two temperature difference values, the environment temperature value is used as a reference, then a standard value corresponding to the environment temperature value is searched through a database table, the standard value is compared with the temperature difference values, and if the temperature difference values are smaller than the standard value, it is indicated that the temperature is normal; otherwise, the alarm module gives an alarm. The temperature measuring device can give an alarm for the temperature out-of-limit fault of the cable elbow-shaped head in time, and can also avoid the potential hazard of insulation breakdown possibly brought to the ring main unit due to the disassembly of the original cable plug.

Description

Technical Field

[0001] The invention belongs to the technical field of temperature measurement of cable joints in ring main unit, and in particular relates to a temperature measurement device for a cable elbow of a ring main unit and an early warning method thereof. Background Art

[0002] With the development of science and technology, electric energy has become one of the cleaner and more environmentally friendly energy sources and has been widely used. However, with the rapid development of the economy, the demand for electric energy is constantly increasing, the user load is constantly expanding, and the reliability pressure of the power supply requirements of the power grid system is increasing, which also brings some new problems. According to the literature, some high-voltage joints and some contacts in the electrical lines often have excessive temperature rise during normal operation in the electrical system, which accelerates the aging of the equipment. At the same time, some cable joints will fail due to long-term high temperature and cause failures. In the power grid, the 10kV ring main unit is the core equipment part of the power distribution and transformation of the small regional power grid. Its operation is of great significance to the power grid, especially at the elbow and joint position of the ring main unit cable, which is prone to problems due to high temperature.

[0003] Since the cable elbow is fully enclosed, high temperature resistant, and insulated, traditional contact temperature measurement cannot effectively measure the accurate temperature. There is no effective and accurate method and related technology for temperature measurement and early warning of T-type cable connectors in ring network cabinets. In particular, it is difficult to ensure the safety of directly measuring the high-potential core temperature and the timeliness of monitoring equipment maintenance without destroying the structural integrity of the connector.

[0004] Some manufacturers have also developed temperature measuring plugs based on electric field power supply. However, for existing ring network cabinets, the original plugs need to be removed and replaced with power supply type temperature measuring plugs when used on site. On the one hand, power outage is required, resulting in reduced power supply reliability. On the other hand, the silicone remaining in the original plug position where the elbow head is installed is difficult to remove, which may cause surface discharge and breakdown of insulation. Summary of the invention

[0005] The purpose of the present invention is to provide a ring network cabinet cable elbow temperature measuring device and its early warning method, which solves the problem that the existing electrical temperature measuring plug needs to be removed when in use, resulting in power outage or surface discharge and insulation breakdown.

[0006] The present invention is achieved through the following technical solutions: On the one hand, the present invention discloses a temperature measuring device for a cable elbow of a ring main unit, comprising a conductive silicone shell, a mainboard is arranged inside the conductive silicone shell, and a single-chip microcomputer and a hollow screw are installed on the mainboard, and the single-chip microcomputer is electrically connected to a static memory, an ambient temperature probe and a plug temperature probe; The plug temperature probe is embedded in the end of the screw rod, and the end of the screw rod extends out of the conductive silicone shell to connect with the plug of the cable elbow; The plug temperature probe is used to measure the temperature of the plug installed in the cable elbow, and the ambient temperature probe is used to measure the temperature of the environment surrounding the cable elbow; The single chip microcomputer is connected to an alarm module; a database table is stored in the static memory; The single-chip microcomputer is used to calculate the temperature difference between the cable plug and the surrounding environment of the cable elbow. Taking the ambient temperature as the reference, the standard temperature difference value corresponding to the ambient temperature value is searched through the database table. If the actual temperature difference is less than the standard temperature difference value, it means that the internal temperature of the cable elbow is normal; otherwise, the alarm module is activated to alarm.

[0007] Further, the database table is a relationship between the temperature difference between the cable plug temperature and the environment when the ambient temperature and the internal temperature of the cable elbow exceed the limit; The actual cable elbow model test yields the temperature curve of the outer side of the plug when the core temperature is at the alarm temperature and at different ambient temperatures.

[0008] Furthermore, a high-energy battery is also packaged on the mainboard.

[0009] Further, the end of the screw rod is connected to a nut at the plug end of the cable elbow.

[0010] Furthermore, the single chip microcomputer is also electrically connected to an RS485 interface.

[0011] Furthermore, the single chip microcomputer is an ARM STM32F103ZET6 single chip microcomputer, and the static memory is an SRAM static memory.

[0012] Furthermore, the single chip microcomputer is electrically connected to a communication circuit board, a radio frequency module is packaged inside the communication circuit board, an output end of the radio frequency module is connected to an antenna, and the antenna is used to transmit the measurement data to a remote host computer.

[0013] Further, the RF module includes a RF transceiver module and a first RF circuit, one end of the first RF circuit is electrically connected to the RF transceiver module, and the other end of the first RF circuit is electrically connected to the antenna; The radio frequency transceiver module has a second radio frequency circuit packaged on one side and a UART universal asynchronous serial transceiver module packaged on the other side.

[0014] On the other hand, the present invention also discloses an early warning method based on the ring network cabinet cable elbow head temperature measuring device, wherein the ring network cabinet cable elbow head temperature measuring device is installed at the original plugging position of the ring network cabinet cable elbow head; The ambient temperature probe measures the temperature of the environment around the cable elbow, and the plug temperature probe measures the temperature of the plug in the cable elbow; The temperature data measured by the ambient temperature probe and the plug temperature probe are read by the single-chip microcomputer. The single-chip microcomputer first calculates the temperature difference between the cable plug and the surrounding environment of the cable elbow, takes the ambient temperature value as a reference, and then searches the database table for the temperature difference standard value corresponding to the ambient temperature value. If the actual temperature difference is less than the temperature difference standard value, it means that the internal temperature of the cable elbow is normal; otherwise, the alarm module is activated to alarm.

[0015] Furthermore, the single chip is electrically connected to a communication circuit board, a radio frequency module is encapsulated inside the communication circuit board, an output end of the radio frequency module is connected to an antenna, and the antenna is connected to a remote host computer; The single chip microcomputer processes the two temperature signals and the alarm signal into radio frequency signals after passing through the radio frequency module; The RF signal is transmitted to the remote host computer through the antenna.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: The invention discloses a temperature measuring device for a cable elbow of a ring network cabinet. The device comprises a mainboard, a single-chip microcomputer and a screw are connected to the mainboard, the single-chip microcomputer is electrically connected to an ambient temperature probe, a plug temperature probe and a communication circuit board, the plug temperature probe is embedded in the screw, when in use, the device can connect the temperature measuring device of the invention to the plug by tightening the screw on a nut of the plug without replacing the plug of the existing cable elbow, the plug temperature probe is embedded in the end of the screw, and the temperature of the plug installed in the cable elbow can be sensed by contact temperature measurement, and the ambient temperature probe measures the temperature of the surrounding environment of the ring network cabinet; two temperature data are transmitted to the single-chip microcomputer, the single-chip microcomputer first calculates two temperature differences, takes the ambient temperature value as a reference, and then mobilizes a database table to judge the size of the standard value corresponding to the ambient temperature value and the temperature difference, if the temperature difference is less than the standard value, it means that the temperature is normal; otherwise, the alarm module is started to alarm. The temperature measuring device of the present invention can timely measure the temperature of the cable elbow and give an early warning, and can also avoid the potential breakdown risk of the ring network cabinet caused by removing the original cable plug, thereby improving the ease of installation and use.

[0017] The most direct benefit of the promotion and use of this invention is that it can realize the real-time monitoring of the temperature of the joints in the switch elbow without making any changes to the existing ring network cabinet, and give timely alarms for joints with temperature exceeding the limit, providing strong guarantee for the quality of power supply and saving a lot of economic losses caused by long power outages. It can further promote the construction of digital operation and maintenance, further popularize automation, and thus improve the overall operation and maintenance level and efficiency.

[0018] Furthermore, the single chip microcomputer processes the two temperature signals and the alarm signal into radio frequency signals after passing through the radio frequency module; the radio frequency signals are transmitted to the remote host computer through the antenna. The remote host computer stores these signal data and is mainly responsible for data display and statistical analysis, so that the temperature measurement device provides data support. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a principle diagram of a temperature measuring device for a cable elbow of a ring main unit of the present invention; Figure 2 It is a structural schematic diagram of a temperature measuring device for a cable elbow of a ring main unit of the present invention; Figure 3 This is a photo of the installation of a temperature measuring device for the elbow head of a ring main unit cable of the present invention; Figure 4 The present invention has obtained the temperature curve of the outer side of the plug at different ambient temperatures when the wire core temperature is 60° (the maximum allowable temperature) through a large amount of historical data testing.

[0020] In the figure: 1. single chip microcomputer; 2. static memory; 3. RS485 interface; 4. ambient temperature probe; 5. plug temperature probe; 6. communication circuit board; 7. RF transceiver module; 8. second RF circuit; 9. UART universal asynchronous serial transceiver module; 10. first RF circuit; 11. antenna; 12. conductive silicone shell; 13. high energy battery; 14. wireless antenna base. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention more clear, the following is further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, not all embodiments.

[0022] The components described and shown in the drawings and embodiments of the present invention may be arranged and designed in various configurations. Therefore, the detailed description of the embodiments of the present invention provided in the following drawings is not intended to limit the scope of the claimed invention, but merely represents a selected embodiment of the present invention. Based on the drawings and embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0023] It should be noted that the terms "comprises", "includes" or any other variations are intended to cover non-exclusive inclusion, so that a process, element, method, article or equipment that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to the process, element, method, article or equipment.

[0024] See also Figure 1-2 The present invention provides a temperature measuring device for a cable elbow of a ring main unit, comprising a conductive silicone shell 12, a mainboard is arranged inside the conductive silicone shell 12, and a single-chip computer 1 is installed on the mainboard, the single-chip computer 1 is electrically connected to a static memory 2, and the single-chip computer 1 is electrically connected to an ambient temperature probe 4 and a plug temperature probe 5.

[0025] More preferably, the single-chip computer 1 is electrically connected to a communication circuit board 6, a radio frequency transceiver module 7 is encapsulated inside the communication circuit board 6, a second radio frequency circuit 8 is encapsulated on one side of the radio frequency transceiver module 7, a UART universal asynchronous serial transceiver module 9 is encapsulated on the other side of the radio frequency transceiver module 7, one end of the radio frequency transceiver module 7 is electrically connected to a first radio frequency circuit 10, and one side of the first radio frequency circuit 10 is electrically connected to an antenna 11.

[0026] Specifically, the conductive silicone shell 12 is made of semi-conductive rubber material, ensuring that the high voltage signal can be discharged reliably.

[0027] In the present invention, preferably, the ambient temperature probe 4 and the plug temperature probe 5 are connected to the mainboard via leads, which can ensure accurate transmission of temperature data and improve the reliability of the system.

[0028] The main board and the communication circuit board 6 are connected by a flat cable, which is convenient for maintenance and replacement, while ensuring the stability of signal transmission.

[0029] The plug temperature probe 5 senses the temperature of the plug in the cable elbow through contact temperature measurement, and can monitor the temperature change of the plug in real time to prevent equipment failure caused by excessive temperature; the plug temperature probe 5, the main board and the communication circuit board 6 are all encapsulated in a conductive silicone shell 12, which has a good electromagnetic shielding effect and protects the internal circuit from external interference.

[0030] The plug temperature probe 5 is embedded in the end of the stud, so that the plug temperature probe 5 and the stud are tightly combined, ensuring the accuracy of temperature measurement and improving the vibration resistance of the probe.

[0031] Preferably, Figure 2 As shown, a high-energy battery 13 and a wireless antenna base 14 are also packaged on the mainboard to provide a permanent power supply for the system and ensure the stability of wireless communication.

[0032] The plug temperature probe 5, the main board and the communication circuit board 6 are all encapsulated in the conductive silicone shell 12 and fixed in the conductive silicone shell 12 with epoxy resin, which enhances the waterproof and dustproof performance of the overall structure and prolongs the service life of the equipment.

[0033] The ambient temperature probe 4 extends from the side wall of the conductive silicone shell 12 and is used to monitor the external ambient temperature.

[0034] The single chip computer 1 is connected with an alarm module; the static memory 2 stores a database table.

[0035] The temperature data measured by the ambient temperature probe 4 and the plug temperature probe 5 are transmitted to the single-chip microcomputer 1, which is used to calculate the temperature difference between the cable plug and the surrounding environment of the cable elbow. The ambient temperature value is used as a reference, and then the temperature difference standard value corresponding to the ambient temperature value is searched through the database table. If the actual temperature difference is less than the temperature difference standard value, it means that the internal temperature of the cable elbow is normal; otherwise, the alarm module is activated to alarm.

[0036] Specifically, the database table is the relationship between the temperature difference between the cable plug temperature and the environment when the ambient temperature and the internal temperature of the cable elbow exceed the limit; The actual cable elbow model test yields the temperature curve of the plug's outer side when the wire core temperature is at the alarm temperature and at different ambient temperatures. Specifically, a large amount of historical data has been tested in the early stage to obtain the temperature curve of the plug's outer side when the wire core temperature is 60° (the highest allowable temperature) and at different ambient temperatures. This temperature curve can be used to determine whether the wire core temperature exceeds the standard. The curve is as follows: Figure 4 shown.

[0037] The features and performances of the present invention are further described in detail below in conjunction with the embodiments.

[0038] Embodiment 1 The present invention discloses a temperature measuring device for a cable elbow of a ring network cabinet, comprising a mainboard, on which a power supply, a single-chip microcomputer 1, and an SRAM static memory 2 are mounted; the single-chip microcomputer 1 is electrically connected to an ambient temperature probe 4 and a plug temperature probe 5, and the SRAM static memory 2 is connected to the single-chip microcomputer 1. The single-chip microcomputer 1 is connected to an alarm module; and the static memory 2 stores a database table.

[0039] Single chip computer 1 is used to calculate the temperature difference between the cable plug and the surrounding environment of the cable elbow, and uses the ambient temperature value as a reference, and then searches the database table for the temperature difference standard value corresponding to the ambient temperature value. If the actual temperature difference is less than the temperature difference standard value, it means that the internal temperature of the cable elbow is normal; otherwise, the alarm module is activated to alarm.

[0040] The single chip microcomputer 1 is an ARM STM32F103ZET6 single chip microcomputer, which has the characteristics of high performance and low power consumption, and improves the processing capability and efficiency of the system.

[0041] Static memory 2 is SRAM static memory, which ensures the rapidity and stability of data storage; there are two interfaces 3, both of which are RS485 interfaces, which improves the anti-interference ability of data transmission and is suitable for complex industrial environments; The ambient temperature probe 4 and the plug temperature probe 5 are sensors for sensing temperature. The probes are connected to the single-chip microcomputer 1 via a communication interface on the mainboard so as to transmit temperature data to the single-chip microcomputer for processing.

[0042] MCU 1: It is the core processing unit of the device, responsible for controlling the operation of the entire system, processing temperature data, executing communication protocols, and managing other peripheral devices.

[0043] SRAM static memory 2: Provides fast storage space for storing data and temporary variables during the operation of the microcontroller to support fast read and write operations of the microcontroller.

[0044] Ambient temperature probe 4: used to measure the temperature of the environment around the ring main unit to monitor the environmental conditions.

[0045] Plug temperature probe 5: used to measure the temperature of the plug in the cable elbow to monitor the thermal state of the plug and prevent overheating.

[0046] Based on the early warning method of the ring main unit cable elbow temperature measuring device, the ring main unit cable elbow temperature measuring device is installed at the original plugging position of the ring main unit cable elbow; The ambient temperature probe 4 measures the temperature of the environment around the ring main unit, and the plug temperature probe 5 measures the temperature of the plug in the cable elbow; The temperature data measured by the ambient temperature probe 4 and the plug temperature probe 5 are transmitted to the single-chip microcomputer 1, which first calculates the two temperature differences, takes the ambient temperature value as a reference, and uses the table lookup method to find the temperature difference standard value corresponding to the ambient temperature value through the database table. If the actual temperature difference is less than the temperature difference standard value, it means that the internal temperature of the cable elbow is normal; otherwise, the alarm module is activated to alarm.

[0047] Embodiment 2 like Figure 1 As shown, the present invention discloses a temperature measuring device for a cable elbow of a ring main unit, comprising a mainboard, a communication circuit board 6 and an antenna 11, wherein the mainboard and the communication circuit board 6 are connected by a flat cable, and the antenna 11 is connected to the communication circuit board; a single-chip microcomputer 1, an SRAM static memory 2 and a communication interface are carried on the mainboard; the communication interface comprises two RS485 interfaces 3 respectively connected to the single-chip microcomputer 1. The single-chip microcomputer 1 is electrically connected to an ambient temperature probe 4, a plug temperature probe 5 and the SRAM static memory 2.

[0048] Specifically, the communication circuit board 6 carries a first radio frequency circuit 10 and a radio frequency transceiver module 7 with a built-in second radio frequency circuit 8 and a UART universal asynchronous serial transceiver module 9 .

[0049] The two RS485 interfaces 3 communicate with external devices in serial mode and are used to exchange data with other acquisition systems.

[0050] The radio frequency transceiver module 7 is a CC1110 radio frequency transceiver module, which has a long communication distance and stable transmission performance, ensuring the reliability of wireless communication.

[0051] CC1110 RF transceiver module 7: is a wireless communication module, including a built-in second RF circuit 8 and a UART universal asynchronous serial transceiver module 9, for realizing wireless data transmission and reception.

[0052] UART universal asynchronous serial transceiver module 9: integrated in the CC1110 radio frequency transceiver module, used to implement serial communication, and can exchange data with the microcontroller 1 through a serial interface.

[0053] The first radio frequency circuit 10 is located on the communication circuit board 6 and cooperates with the CC1110 radio frequency transceiver module 7 to process radio frequency signals; the first radio frequency circuit should be a radio frequency power amplifier for increasing the power of radio frequency transmission.

[0054] Antenna 11: connected to the first radio frequency circuit on the communication circuit board 6, used for transmitting and receiving wireless signals to realize wireless communication function; the antenna 11 transmits two temperature values ​​and an alarm signal to a remote host computer.

[0055] Based on the early warning method of the ring main unit cable elbow temperature measuring device, the ring main unit cable elbow temperature measuring device is installed at the original plugging position of the ring main unit cable elbow; The ambient temperature probe 4 measures the temperature of the environment around the ring main unit, and the plug temperature probe 5 measures the temperature of the plug in the cable elbow; The temperature data measured by the ambient temperature probe 4 and the plug temperature probe 5 are transmitted to the single-chip microcomputer 1, which first calculates the two temperature differences, takes the ambient temperature value as a reference, and then searches the temperature difference standard value corresponding to the ambient temperature value through the database table. If the actual temperature difference value is less than the temperature difference standard value, it means that the internal temperature of the cable elbow is normal; otherwise, the alarm module is activated to alarm; The single chip microcomputer 1 processes the two temperature signals and the alarm signal into radio frequency signals after passing through the radio frequency module; The radio frequency signal is transmitted to a remote host computer via antenna 11.

[0056] The remote host computer stores these signal data and is mainly responsible for data display and statistical analysis for subsequent accurate judgment.

[0057] like Figure 3 As shown, it is a photo of the actual installation. At present, there is a nut in the middle of the end of the cable plug. The screw rod (with the temperature measuring probe embedded) of the present invention can be fixed by directly screwing it on the nut, and the installation and disassembly are very convenient.

[0058] The main purpose of the ring main unit cable elbow head temperature measuring device designed in the present invention is to monitor temperature problems and notify the operation and maintenance personnel to deal with them as soon as possible. Because there is currently no monitoring means, it is impossible for the staff to watch in real time. Once long-term high temperature occurs, the on-site ring main unit will be burned, and the loss of an accident will reach millions of yuan. Therefore, the temperature phenomenon can be monitored through the present invention and relevant personnel can be notified in time.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A temperature measuring device for a cable elbow of a ring main unit, characterized in that: It comprises a conductive silicone shell (12), a mainboard is arranged inside the conductive silicone shell (12), a single-chip computer (1) and a hollow screw are mounted on the mainboard, and the single-chip computer (1) is electrically connected to a static memory (2), an ambient temperature probe (4) and a plug temperature probe (5); The plug temperature probe (5) is embedded in the end of the screw rod, and the end of the screw rod extends out of the conductive silicone shell (12) for connecting with the plug of the cable elbow; The plug temperature probe (5) is used to measure the temperature of the plug installed in the cable elbow, and the ambient temperature probe (4) is used to measure the temperature of the environment surrounding the cable elbow; The single chip computer (1) is connected to an alarm module; a database table is stored in the static memory (2); The single chip computer (1) is used to calculate the temperature difference between the cable plug and the surrounding environment of the cable elbow, taking the ambient temperature value as a reference, and then searching the temperature difference standard value corresponding to the ambient temperature value through the database table. If the actual temperature difference value is less than the temperature difference standard value, it means that the internal temperature of the cable elbow is normal; otherwise, the alarm module is activated to alarm.

2. A ring main unit cable elbow temperature measuring device according to claim 1, characterized in that: The database table is the relationship between the temperature difference between the cable plug temperature and the environment when the ambient temperature and the internal temperature of the cable elbow exceed the limit; The actual cable elbow model test yields the temperature curve of the outer side of the plug when the core temperature is at the alarm temperature and at different ambient temperatures.

3. The temperature measuring device for the elbow head of a ring main unit cable according to claim 1 is characterized in that: A high-energy battery (13) is also packaged on the main board.

4. The temperature measuring device for the elbow head of a ring main unit cable according to claim 1 is characterized in that: The end of the threaded rod is connected to the nut on the plug end of the cable elbow.

5. The temperature measuring device for the elbow head of a ring main unit cable according to claim 1 is characterized in that: The single chip computer (1) is also electrically connected to an RS485 interface (3).

6. The temperature measuring device for the elbow head of a ring main unit cable according to claim 1, characterized in that: The single chip microcomputer (1) is an ARM STM32F103ZET6 single chip microcomputer, and the static memory (2) is an SRAM static memory.

7. A temperature measuring device for a cable elbow of a ring main unit according to any one of claims 1 to 6, characterized in that: The single chip computer (1) is electrically connected to a communication circuit board (6), a radio frequency module is encapsulated inside the communication circuit board (6), an output end of the radio frequency module is connected to an antenna (11), and the antenna (11) is used to transmit measurement data to a remote host computer.

8. The temperature measuring device for the elbow head of a ring main unit cable according to claim 7, characterized in that: The radio frequency module comprises a radio frequency transceiver module (7) and a first radio frequency circuit (10), wherein one end of the first radio frequency circuit (10) is electrically connected to the radio frequency transceiver module (7) and the other end is electrically connected to the antenna (11); The radio frequency transceiver module (7) is packaged with a second radio frequency circuit (8) on one side, and is packaged with a UART universal asynchronous serial transceiver module (9) on the other side.

9. The early warning method based on the temperature measuring device of the elbow head of the ring main unit cable according to any one of claims 1 to 8 is characterized in that: Install the ring main unit cable elbow temperature measuring device at the original plugging position of the ring main unit cable elbow; The ambient temperature probe (4) measures the temperature of the environment around the cable elbow, and the plug temperature probe (5) measures the temperature of the plug in the cable elbow; The temperature data measured by the ambient temperature probe (4) and the plug temperature probe (5) are read by the single-chip computer (1). The single-chip computer (1) first calculates the temperature difference between the cable plug and the surrounding environment of the cable elbow, takes the ambient temperature value as a reference, and then searches the database table for the temperature difference standard value corresponding to the ambient temperature value. If the actual temperature difference value is less than the temperature difference standard value, it means that the internal temperature of the cable elbow is normal; otherwise, the alarm module is activated to alarm.

10. The early warning method according to claim 9, characterized in that: The single chip computer (1) is electrically connected to a communication circuit board (6), a radio frequency module is encapsulated inside the communication circuit board (6), an output end of the radio frequency module is connected to an antenna (11), and the antenna (11) is connected to a remote host computer; The single chip microcomputer (1) processes the two temperature signals and the alarm signal into radio frequency signals after passing through the radio frequency module; The radio frequency signal is transmitted to a remote host computer via an antenna (11).

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