Intelligent monitoring system for distribution and transformation equipment

发布时间:2013-03-26 20:46:31

1、 The necessity of temperature monitoring of electrical equipment
During the long-term operation of electrical equipment, under the conditions of high voltage and strong current, the contact area decreases and the contact resistance increases due to the pollution of gas dust, oxidation of contact, electrochemical reaction, aging and loosening of mechanical structure, which leads to the high temperature of contact and forms a vicious circle, Serious accidents that will lead to fire and even explosion are likely to cause huge economic losses and even personal injury, and have a serious negative impact on the corporate image. Therefore, accurate, real-time and on-line monitoring of key conductor connection parts in electrical equipment has strong necessity, high economic value and social significance.
2、 Traditional temperature measurement technology can not meet the requirements
1. The traditional temperature sensor can not directly contact the live conductor, so it can only be installed on the outer layer of the insulation skin, and the temperature measurement result is very different from the real temperature of the conductor.
2. Traditional temperature sensor installed in electrical equipment has potential safety hazards: wired sensor has creepage risk, battery powered sensor has the risk of battery compound explosion, CT ring of CT power sensor has the risk of severe heating due to poor contact.
3. The traditional temperature sensor is generally PCB circuit board structure, long-term in high temperature, strong electromagnetic field environment, easy to damage or failure, service life is not long, quality and reliability is not high.
4. Relying on infrared temperature gun for manual inspection, it is impossible to monitor the electrical equipment in real time, online and uninterrupted; Moreover, 6kV, 10kV and other high-voltage electrical equipment can not open the cabinet under the condition of power on, and can not measure the temperature of its internal conductor.

3、 Online temperature monitoring of electrical equipment is in line with the State Grid policy
On March 8, 2019, the teleconference on the construction of ubiquitous power Internet of things of State Grid Co., Ltd. was held in Beijing. The meeting implemented the spirit of the fourth workers' Congress of the company and the work conference in 2019, made comprehensive arrangements for the construction of ubiquitous power Internet of things, mobilized the whole company to further unify their thinking, enhance their understanding, overcome difficulties, and accelerate the implementation of the strategy of "three types, two networks, world-class".
At present, many provinces have started the pilot work of ubiquitous power Internet of things. In the next five years, huge funds will be invested to support the construction of ubiquitous power Internet of things, which not only fundamentally improves the quality and reliability of power grid operation, but also drives domestic demand from the aspect of science and technology industry, and promotes economic development and transformation.

1、Product introduction

1、The function sends the temperature measurement command to the antenna through the feeder and receives the temperature measurement data fed back by the antenna. After analysis and processing, the data is transmitted to the outside through Modbus communication protocol. With its own 485 interface, the network is flexible, supports various protocol conversion, and can transmit data through 485 bus, cat network cable, DTU, Lora and other wired or wireless modes.
Rated voltage: AC / DC 85 ~ 265 wide power supply
Working frequency: 920mhz ~ 925mhz
Working temperature: - 20 ℃~ + 70 ℃
Communication interface: RS485 / mdobus RTU
With CRC check code verification function.

It is installed in the secondary room, weak current room, metering room and other low voltage cabins of electrical equipment. As shown in the figure below:

Send the temperature measurement command to the sensor and receive the temperature measurement data from the sensor.
2. Parameters
Working frequency: 920mhz ~ 925mhz
Working temperature: - 40 ℃~ + 150 ℃

It can be directly adsorbed on the inner wall of the metal cabin where the sensor is located with a strong magnet, and can also be installed through screws after drilling. As shown in the white and yellow square structure on the metal wall below:

10kVSwitch cabinet circuit breaker room        10kVRing main unit cable           10kVSwitch cable entry room
3、Temperature sensor
Contact the conductor directly to measure the temperature, and send the temperature measurement data to the antenna through wireless signal.
orking frequency: 920mhz-925mhz

Working temperature: - 40 ℃~ + 150 ℃

Measurement range: - 40 ℃ ~ + 125 ℃

Measurement error: ± 2℃

Truly passive wireless, no external power supply, no built-in battery, no current or voltage induction power

3. Installation

The passive sensor of this system has the characteristics of small volume, beautiful appearance, exquisite structure and easy installation. It has a variety of appearance design, which is very convenient to install in the copper bar, bolt, cable connection, circuit breaker moving contact pad and other positions. At present, there are mainly three types of sensors as follows:

(1) Flat pad sensor

According to the ABC three color separation, the new ultra-thin passive sensor can be used as a flat pad and fixed on the bolt with nuts. It is suitable for temperature monitoring of important conductor connection parts of various equipment, such as station area, low-voltage distribution box, box transformer, etc.

Installation example:

                 380V circuit breaker                              10kV cable joint                           Incoming and outgoing lines of box transformer                           Incoming and outgoing lines of transformer in substation area

(2) Nut sensor

The temperature sensor integrated with the nut can replace the original nut and be directly installed on the bolt. At present, it is mainly used in the temperature monitoring of 10kV cable terminal in the elbow head of ring main unit.

Installation example:

  ( 3) Moving contact sensor

The main body material of the small moving contact sensor is microwave ceramic (yellow part), and the installation accessory specially designed for the moving contact pad is nylon glass fiber (black part), which is resistant to high temperature and high voltage, anti breakdown and tip discharge, and is easy and stable to install.

Installation example:

             6kV switch cabinet of Daqiao Hydropower Station                      10kV switch cabinet of Nanwang substation

          6kV switch cabinet of Huaneng Fuzhou Power Plant                    10kV switch cabinet in government distribution room

4、System features
  1. he temperature sensor is designed based on the most advanced RFID technology to achieve real passivity, without built-in batteries, external wires, or current sensing (CT) or voltage sensing (PT).
    The temperature sensor is completely separated from the signal receiving device, and the data is transmitted through the wireless signal, and the wireless signal can penetrate materials other than metal and liquid, and can also be transmitted when sealed in the insulation layer.
    The material of the temperature sensor is specially designed for high voltage environment. It has excellent electrical insulation with high volume resistance, high breakdown voltage resistance, no breakdown, creepage, explosion and other hidden dangers, and can withstand high temperature above 200 ℃.
    The temperature sensor is installed on the surface of the charged conductor to collect the temperature data and accurately feed back the real temperature of the conductor in the most direct way. The temperature measurement error is controlled within 10% ± Within 2 ℃, the accuracy is 0.1 ℃.
    The system can collect and upload temperature data 24 hours a day without interruption, and the transportation and inspection personnel can check the temperature status of the equipment anytime and anywhere, saving time and effort; With the temperature rise alarm function, the abnormal temperature rise can be found in time, the hidden trouble can be solved in advance, and the efficiency, effect and benefit of the operation and inspection work can be greatly improved.
    Simplify the system installation and debugging, so that the transportation and inspection personnel can be quickly installed in place after simple training, and the equipment can be easily debugged before power on.
    The system runs stably and reliably, the sensor has a long service life, and is free of manual maintenance after installation and operation.
    The background of the system has rich and powerful functions, which can not only accurately display the real-time temperature, maximum temperature difference, interphase temperature difference and other data of each temperature measuring point, but also store historical data, form reports and draw curves.