Cable anti-theft and anti-cutting and joint temperature measurement monitoring device

Abstract

The utility model aims to provide the high-voltage cable anti-theft and anti-cutting and joint temperature measurement integrated monitoring device which is low in cost, small in size, high in protection level and capable of being flexibly configured. A single-chip microcomputer module (1) used for analog-to-digital conversion, data processing and communication control is arranged in the shell. The hardware watchdog module (2) is connected with the single chip microcomputer module and is used for automatically resetting the system when detecting that the single chip microcomputer works abnormally; the CAN bus interface (3) is connected with the single chip microcomputer module and is used for communicating with superior master equipment and subordinate similar slave equipment and providing a power supply for the monitoring device; a vibration sensor module (4) connected with the single-chip microcomputer module and used for monitoring vibration signals; a plurality of temperature measurement sensors (5) used for sensing the temperature of the cable joint; and the temperature signal conditioning module (6) is communicated with the temperature measuring sensor and is connected to the single chip microcomputer module after preprocessing the temperature analog signal. The device is applied to the technical field of power cable on-line monitoring.

Description

Technical Field

[0001] The utility model relates to the technical field of online monitoring of power cables, in particular to a cable theft prevention and joint temperature measurement monitoring device. Background Art

[0002] At present, with the acceleration of my country's urbanization process and the improvement of the living standards of urban and rural people, the electricity load has increased significantly. In the power distribution networks of cities, especially large and medium-sized cities, the proportion of cable applications is getting higher and higher.

[0003] The most common problems of high-voltage cables during long-term operation are insulation aging and insulation damage. In particular, cable joint accessories, which are the most difficult to control in terms of quality, are more prone to insulation failure. Power cable joints are easily affected by insulation materials, contact resistance, or manufacturing processes, which can cause excessive temperature and abnormal temperature rise in cable joints. If not handled in time, it will further cause serious insulation breakdown. Therefore, monitoring the operating status of power cable joints based on temperature is of great significance for effectively preventing cable accidents.

[0004] Existing cable joint temperature measurement methods include two categories: electrical signal temperature measurement methods such as thermocouples and integrated sensors, and optical signal temperature measurement methods such as infrared and fiber Raman scattering. Among them, because the cables are buried deep underground, the operating environment is harsh, and they are often soaked in water, the infrared principle of optical signal temperature measurement is inconvenient to install and is not suitable for the operating environment of cable joints. The distributed fiber optic temperature measurement based on the fiber Raman scattering principle requires a temperature measurement host and a temperature measurement optical cable. It is expensive, has poor reliability, and has a limited monitoring distance. It is only suitable for monitoring important high-voltage cable lines within 15km, and it is difficult to meet the low-cost monitoring requirements of cable joints of various voltage levels. Although there are some electrical signal temperature measurement devices, they are mainly used for temperature measurement in industrial sites, and cannot meet the harsh working conditions of cables buried underground and soaked in water. The products are not very targeted and have poor reliability and adaptability.

[0005] In addition to cable insulation failure, due to the particularity and danger of high-voltage cables, it is necessary to monitor the vibration and anti-theft status of power cables in real time to prevent the running cables from being stolen and damaged by illegal elements, and to ensure the safety of power equipment and personnel. The existing commonly used solution is to use optical fiber vibration monitoring devices to monitor the vibration and anti-theft status of cables. Such devices require the installation of a monitoring host in the monitoring room of the substation, and the vibration information is sensed by the optical fiber in the cable laying. The engineering cost is high, and the vibration data is complicated. There is a lack of effective data cleaning and extraction algorithms, and the alarm is frequently rejected and false alarms are frequent. Due to the cost and detection effect, it is only suitable for a small number of key cable projects and is difficult to promote on a large scale. Although there are also anti-theft detection devices designed with acceleration sensors, the device has a single function and is composed of two parts: anti-theft sensor and acquisition host. It is large in size, inconvenient to install, and less used.

[0006] In summary, the current cable anti-theft cutting and joint temperature measurement either rely on optical fiber temperature measurement or optical fiber vibration detection, which is not only costly, but also difficult to install and has a low cost-performance ratio; or use decentralized, single-function temperature and vibration monitoring devices, which have high installation, construction and operation and maintenance costs, limiting the promotion and application of similar products. Utility Model Content

[0007] The technical problem to be solved by the utility model is to overcome the shortcomings of the prior art and provide a low-cost, small-volume, high-protection-level and flexibly configurable integrated monitoring device for high-voltage cable anti-theft and joint temperature measurement. A single device integrates a single module to simultaneously realize the cable joint multi-point temperature measurement function and cable anti-theft and anti-cutting status monitoring, which can be used for surface temperature monitoring of cable joints of various voltage levels and cable anti-external breakage and anti-theft monitoring.

[0008] The technical solution adopted by the utility model is that the utility model comprises a housing, and the housing is provided with:

[0009] Microcontroller modules for analog-to-digital conversion, data processing, and communication control;

[0010] A hardware watchdog module connected to the single-chip microcomputer module and used to automatically reset the system when abnormal operation of the single-chip microcomputer is detected;

[0011] A CAN bus interface connected to the single-chip microcomputer module, used for communicating with the upper-level master device and the lower-level similar slave devices and providing power to the monitoring device;

[0012] A vibration sensor module connected to the single chip microcomputer module and used to monitor vibration signals;

[0013] Several temperature sensors for sensing the temperature of the cable joints;

[0014] A temperature signal conditioning module communicates with the temperature measuring sensor and is used for preprocessing the temperature simulation signal and connected to the single chip microcomputer module.

[0015] It can be seen from the above scheme that the use of several temperature sensors can realize multi-point temperature measurement of cable joints at the same time; the use of a unified shell device is small in size, low in cost, easy to install, and does not require changes to existing lines. It is suitable for large-scale installation, waterproof and explosion-proof, with a high level of protection, and is suitable for harsh cable operating environments; in addition, through the setting of the CAN bus interface, multiple devices can be connected online with flexible configuration; and the vibration sensor module can monitor the displacement, velocity and acceleration analog quantities in multiple directions, which can effectively prevent high-voltage cables from being stolen and cut; the utility model device simultaneously realizes the multi-point temperature measurement function of cable joints and the cable anti-theft and anti-cutting status monitoring, and can be used for surface temperature monitoring of cable joints of various voltage levels and cable anti-external breakage and anti-theft monitoring.

[0016] Furthermore, the CAN bus interface is connected with an upper power supply and communication plug and a lower power supply and communication plug, the upper power supply and communication plug communicates with the upper master device and provides power for the monitoring device, and the lower power supply and communication plug is connected with the single-chip microcomputer module and the upper power supply and communication plug, and is connected to the lower similar slave device. It can be seen that by setting up a CAN bus interface for connecting lower and upper devices, multi-device cascading is achieved, which simplifies the on-site wiring during batch installation along the cable path and reduces the cable cost; using the CAN bus interface for cascade communication, the communication reliability is good and supports the cascading of more than 100 devices.

[0017] Furthermore, the temperature sensor is connected to the temperature signal conditioning module via a temperature measuring aviation plug. It can be seen that the waterproof temperature measuring aviation plug is used to access the internal circuit of the device, which is plug-and-play on site and easy to install.

[0018] Furthermore, the vibration sensor module adopts a three-axis micro-electromechanical system acceleration sensor. It can be seen that the single-chip microcomputer module can obtain the position, speed and acceleration in three directions through the three-axis micro-electromechanical system acceleration sensor, determine whether the cable is abnormally moved, and achieve the purpose of anti-theft and cutting monitoring.

[0019] Furthermore, the temperature signal conditioning module pre-processes the signal collected by the temperature sensor before analog-to-digital sampling, and the pre-processed signal passes through a 4-channel analog multiplexer and enters the analog-to-digital converter of the single-chip module for conversion from analog signal to digital signal. It can be seen that the signal after pre-processing has higher accuracy, which makes it more convenient for the subsequent single-chip module to process the signal.

[0020] In addition, the number of the temperature measuring sensors is set to three, and the three temperature measuring sensors are respectively set at three different positions on the product to be tested. It can be seen that by using three temperature measuring sensors, a single device can be used to measure the temperature of different areas of the same phase cable joint, and the multi-point temperature measurement target of the key cable joint can be achieved.

[0021] Furthermore, the temperature measurement plug adopts a 10-core waterproof plug; the upper power supply and communication plug and the lower power supply and communication plug both adopt a 6-core waterproof plug. It can be seen that the waterproof plug ensures that the device can be used in harsh environments, making the application scenarios of the device more diverse.

[0022] In addition, the shell of the monitoring device is made of aluminum alloy, and the inside of the shell is filled with epoxy resin potting glue. It can be seen that the shell of the device is made of aluminum alloy, and the inside of the shell is filled with epoxy resin potting glue, which has the characteristics of insulation, waterproofness, and corrosion resistance. At the same time, the external interface adopts a waterproof aviation plug connector, and the device is waterproof and dustproof, and can work for a long time in conditions such as soaking in water and buried underground.

[0023] Furthermore, the single-chip microcomputer module is selected from the single-chip microcomputer model STM32L431RCT6; the hardware watchdog module is selected from the chip model TPL5010DDCR; the vibration sensor module is selected from the 3-axis acceleration sensor chip model ADXL357; and the temperature sensor adopts a miniature ultra-thin patch type Pt100 platinum thermal resistor temperature sensor.

[0024] More specifically, the temperature signal conditioning module includes a voltage-stabilizing reference source chip, a first resistor to a tenth resistor, an operational amplifier chip, and a first capacitor to a third capacitor. The voltage-stabilizing reference source chip and the first resistor, the second resistor, and the third resistor constitute a reference power supply. The fourth resistor, the fifth resistor, the sixth resistor, and the temperature sensor connected to the monitoring device constitute a measuring bridge. When the resistance value of the temperature sensor is not equal to the resistance value of the sixth resistor, the measuring bridge outputs a pressure difference signal. The pressure difference signal outputs an expected voltage signal after passing through a differential amplifier circuit composed of the operational amplifier chip, the seventh resistor, the eighth resistor, the ninth resistor, and the tenth resistor. The expected voltage signal enters the analog-to-digital converter inside the single-chip module after passing through a multi-way analog switch, and the first capacitor to the third capacitor perform filtering. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a simple structural block diagram of the utility model;

[0026] Figure 2 Schematic diagram of the circuit of the temperature signal conditioning module. DETAILED DESCRIPTION

[0027] like Figure 1 As shown, the utility model includes a housing, in which is arranged:

[0028] Single chip microcomputer module 1 for analog-to-digital conversion, data processing and communication control;

[0029] A hardware watchdog module 2 connected to the single-chip microcomputer module 1 and used to automatically reset the system when an abnormal operation of the single-chip microcomputer is detected;

[0030] A CAN bus interface 3 connected to the single-chip microcomputer module 1, used for communicating with an upper-level master device and lower-level similar slave devices and providing power to the monitoring device;

[0031] A vibration sensor module 4 connected to the single chip computer module 1 and used to monitor vibration signals;

[0032] A plurality of temperature sensors 5 for sensing the temperature of the cable joint;

[0033] A temperature signal conditioning module 6 which communicates with the temperature sensor 5 and is used for preprocessing the temperature simulation signal and is connected to the single chip computer module 1 .

[0034] The CAN bus interface 3 is connected to an upper power supply and communication air plug 7 and a lower power supply and communication air plug 8. The upper power supply and communication air plug 7 communicates with the upper master device and provides power for the monitoring device. The lower power supply and communication air plug 8 is connected to the single-chip microcomputer module 1 and the upper power supply and communication air plug 7, and is connected to the lower similar slave device. The temperature sensor 5 is connected to the temperature signal conditioning module 6 through a temperature measurement air plug 9. The vibration sensor module 4 adopts a three-axis micro-electromechanical system acceleration sensor. The temperature signal conditioning module 6 pre-processes the signal collected by the temperature sensor 5 before analog-to-digital sampling. The pre-processed signal passes through a 4-channel analog multiplexer and enters the analog-to-digital converter of the single-chip microcomputer module 1 to convert the analog signal to a digital signal. The number of the temperature sensors 5 is set to three, and the three temperature sensors 5 are respectively arranged at three different positions on the product to be tested.

[0035] The temperature measuring aviation plug 9 adopts a 10-core waterproof aviation plug; the upper power supply and communication aviation plug 7 and the lower power supply and communication aviation plug 8 both adopt a 6-core waterproof aviation plug. The outer shell of the monitoring device adopts an aluminum alloy shell, and the inside of the shell is filled with epoxy resin potting glue.

[0036] The single-chip microcomputer module 1 is selected from a single-chip microcomputer of model STM32L431RCT6; the hardware watchdog module 2 is selected from a chip of model TPL5010DDCR; the vibration sensor module 4 is selected from a 3-axis acceleration sensor chip of model ADXL357; and the temperature sensor 5 adopts a miniature ultra-thin patch type Pt100 platinum thermal resistor temperature sensor.

[0037] The temperature signal conditioning module 6 includes a voltage stabilizing reference source chip U1, a first resistor R1 to a tenth resistor R10, an operational amplifier chip U2, and a first capacitor C1 to a third capacitor C3. The voltage stabilizing reference source chip U1 and the first resistor R1, the second resistor R2 and the third resistor R3 form a reference power supply. The fourth resistor R4, the fifth resistor R5, the sixth resistor R6 and the temperature sensor 5 connected to the monitoring device form a measuring bridge. When the resistance value of the temperature sensor 5 is not equal to the resistance value of the sixth resistor R6, the measuring bridge outputs a pressure difference signal, and the pressure difference signal outputs an expected voltage signal after passing through a differential amplifier circuit composed of the operational amplifier chip U2, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9 and the tenth resistor R10. The expected voltage signal enters the analog-to-digital converter inside the single-chip module 1 after passing through a multi-way analog switch, and the first capacitor C1 to the third capacitor C3 are filtered.

[0038] More specifically, the single-chip microcomputer module 1 adopts the STM32L431RCT6 single-chip microcomputer chip of STMicroelectronics, which is a low-cost, ultra-low-power 32-bit single-chip microcomputer with a main frequency of 80MHz, RAM 64K bytes, Flash 256K bytes, and 64 pins. The chip has rich peripherals, including a high-speed ADC that achieves 16-bit sampling accuracy through hardware oversampling technology, 3 I2C interfaces, 4 universal serial asynchronous communication interfaces, 1 controller area network CAN bus interface, etc. The resources fully meet the application requirements of the cable anti-theft and joint temperature measurement monitoring device. Reflecting the device, the ADC inside the single-chip microcomputer chip is used for analog-to-digital conversion of the cable joint temperature, and there is no need to add an analog-to-digital converter chip, which can reduce the hardware cost. The I2C communication interface of the single-chip microcomputer chip is used to connect the acceleration sensor, and the controller area network CAN bus is used for the communication interaction between the monitoring device and the lower-level similar slave device and the upper-level master device.

[0039] The hardware watchdog module 2 uses the TPL5010DDCR chip from Texas Instruments, which is a nanowatt-level power consumption system timer with watchdog function and manual reset function. The optional timing interval is between 100 milliseconds and 7200 seconds. The monitoring device resets the timer every 15 minutes. Once the monitoring device operates abnormally and the timer is not reset in time, the chip will reset the monitoring device.

[0040] The vibration sensor module 4 uses the ADXL357 3-axis acceleration sensor chip of Analog Devices, which has an I2C digital output interface and features an optional measurement range, low noise density, low offset drift, and low power consumption. The single-chip microcomputer module 1 directly reads the data of the sensor chip through the I2C chip interface.

[0041] The temperature sensor 5 uses a micro-ultra-thin patch-type Pt100 platinum thermal resistor temperature sensor, which allows the temperature probe to fit tightly with the curved surface of the cable connector, thereby ensuring that each ultra-thin surface Pt100 platinum thermal resistor temperature sensing rod has good insulation and fast thermal conductivity. At the same time, industrial-grade resin is used as the temperature probe protection tube, so that each Pt100 platinum thermal resistor probe has better thermal conductivity and higher strength, and the sensor has better pressure resistance and higher measurement performance.

[0042] The temperature signal conditioning module 6 adopts Figure 2 Circuit diagram shown. Among them, a 3V reference power supply is generated by a voltage-stabilizing reference source chip U1 (TL431ASF), a first resistor R1 (300 ohms), a second resistor R2 (200 ohms), and a third resistor R3 (1k ohms); a fourth resistor R4 (2k ohms), a fifth resistor R5 (2k ohms), a sixth resistor R6 (75 ohms) and a three-wire Pt100 platinum thermal resistor of the access device are used to form a measuring bridge. When the resistance value of the Pt100 platinum thermal resistor is not equal to the resistance value of the sixth resistor R6, the measuring bridge outputs a pressure difference signal, and the pressure difference signal outputs a voltage signal of a desired size after passing through a differential amplifier circuit composed of an operational amplifier chip U2 (SGM8932), a seventh resistor R7 (1k ohm), an eighth resistor R8 (1k ohm), a ninth resistor R9 (20k ohms), and a tenth resistor R10 (20k ohms). The voltage signals output by the three groups of signal conditioning circuits enter the analog-to-digital converter inside the single-chip module 1 after passing through a multi-channel analog switch. In addition, the first capacitor C1 (0.1uF), the second capacitor C2 (1uF), the third capacitor C3 (0.1uF) and other capacitors play a filtering role, thereby increasing the anti-interference performance of the circuit. Figure 2 In the embodiment, the Pt-G connection pin, the Pt-1 connection pin and the Pt-2 connection pin are connected to the three-wire Pt100 platinum thermal resistor. The Pt-Vout connection pin is connected to the analog-to-digital converter through a multi-channel analog switch.

[0043] In addition, the monitoring device uses two 6-core waterproof upper power supply and communication aviation plugs 7 and the lower power supply and communication aviation plug 8, including 2-core DC24V power supply, 3-core controller area network CAN bus and other wiring definitions. After the DC24V power supply enters the device, it is converted to a certain level to power the monitoring device. After entering the device, the controller area network CAN bus passes through the driver chip and then connects to the single-chip microcomputer module 1.

[0044] In addition, the monitoring device uses a waterproof 10-core temperature measurement waterproof aviation plug, which is connected to three external Pt100 thermal resistors, and each Pt100 thermal resistor includes three wires.

[0045] In addition, the shell of the monitoring device is made of aluminum alloy, and the inside of the shell is filled with epoxy resin potting glue. The device as a whole has the characteristics of insulation, waterproofness, and corrosion resistance, which meets the environmental requirements of cable joint operating conditions.

[0046] Finally, it should be emphasized that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A cable anti-theft and joint temperature monitoring device, characterized in that: It comprises a housing, in which are arranged: A single chip microcomputer module (1) for analog-to-digital conversion, data processing and communication control; A hardware watchdog module (2) connected to the single-chip microcomputer module (1) and used to automatically reset the system when abnormal operation of the single-chip microcomputer is detected; A CAN bus interface (3) connected to the single-chip microcomputer module (1) and used for communicating with an upper-level master device and lower-level similar slave devices and providing power to the monitoring device; A vibration sensor module (4) connected to the single chip computer module (1) and used to monitor vibration signals; A plurality of temperature sensors (5) for sensing the temperature of the cable joint; A temperature signal conditioning module (6) that communicates with the temperature measuring sensor (5) and is used for preprocessing the temperature simulation signal and is connected to the single chip computer module (1).

2. A cable anti-theft and joint temperature monitoring device according to claim 1, characterized in that: The CAN bus interface (3) is connected to an upper power supply and communication aviation plug (7) and a lower power supply and communication aviation plug (8); the upper power supply and communication aviation plug (7) communicates with an upper master device and provides power for a monitoring device; the lower power supply and communication aviation plug (8) is connected to the single-chip computer module (1) and the upper power supply and communication aviation plug (7), and is connected to a lower-level slave device of the same type.

3. A cable anti-theft and joint temperature monitoring device according to claim 2, characterized in that: The temperature sensor (5) and the temperature signal conditioning module (6) are connected via a temperature measurement aviation plug (9).

4. A cable theft prevention and joint temperature monitoring device according to claim 1, characterized in that: The vibration sensor module (4) adopts a three-axis micro-electromechanical system acceleration sensor.

5. A cable anti-theft and joint temperature monitoring device according to claim 3, characterized in that: The temperature signal conditioning module (6) performs preprocessing on the signal collected by the temperature measuring sensor (5) before analog-to-digital sampling, and the preprocessed signal passes through a 4-channel analog multiplexer and enters the analog-to-digital converter of the single-chip computer module (1) for conversion from analog signal to digital signal.

6. A cable theft prevention and joint temperature monitoring device according to claim 5, characterized in that: The number of the temperature measuring sensors (5) is set to three, and the three temperature measuring sensors (5) are respectively arranged at three different positions on the product to be measured.

7. A cable theft prevention and joint temperature monitoring device according to claim 3, characterized in that: The temperature measurement aviation plug (9) adopts a 10-core waterproof aviation plug; the upper power supply and communication aviation plug (7) and the lower power supply and communication aviation plug (8) both adopt a 6-core waterproof aviation plug.

8. The cable anti-theft and joint temperature monitoring device according to claim 1 is characterized by: The shell of the monitoring device is made of aluminum alloy, and the inside of the shell is filled with epoxy resin potting glue.

9. The cable anti-theft and joint temperature monitoring device according to claim 1 is characterized by: The single-chip microcomputer module (1) is selected from a single-chip microcomputer of model STM32L431RCT6; the hardware watchdog module (2) is selected from a chip of model TPL5010DDCR; the vibration sensor module (4) is selected from a 3-axis acceleration sensor chip of model ADXL357; and the temperature sensor (5) is a micro-ultra-thin patch type Pt100 platinum thermal resistor temperature sensor.

10. A cable theft prevention and joint temperature monitoring device according to claim 9, characterized in that: The temperature signal conditioning module (6) comprises a voltage stabilizing reference source chip (U1), a first resistor (R1) to a tenth resistor (R10), an operational amplifier chip (U2) and a first capacitor (C1) to a third capacitor (C3); the voltage stabilizing reference source chip (U1) and the first resistor (R1), the second resistor (R2) and the third resistor (R3) form a reference power supply; the fourth resistor (R4), the fifth resistor (R5), the sixth resistor (R6) and the temperature measuring sensor (5) connected to the monitoring device form a measuring bridge; when the temperature measuring sensor (5) is connected to the monitoring device When the resistance value of the sensor (5) is not equal to the resistance value of the sixth resistor (R6), the measuring bridge outputs a pressure difference signal, and the pressure difference signal outputs a desired voltage signal after passing through a differential amplifier circuit composed of the operational amplifier chip (U2), the seventh resistor (R7), the eighth resistor (R8), the ninth resistor (R9) and the tenth resistor (R10). The desired voltage signal enters the analog-to-digital converter inside the single-chip computer module (1) after passing through a multi-channel analog switch, and is filtered by the first capacitor (C1) to the third capacitor (C3).

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