Ankerui Yu Jiahao
Summary:Because the space in the high-voltage switchgear is closed, and the safety distance of the electrical equipment is very small, when the temperature in the switchgear rises, it will lead to the decline of air insulation and cause failure, so it is of great significance for the high-voltage switchgear to adopt first-class temperature measurement technology. In response to this problem, this paper analyzes the necessity of the application of temperature measurement technology in high-voltage switchgear, and analyzes the specific characteristics of temperature measurement technology, hoping to provide some references to make high-voltage switchgear more stable operation.
Keywords:High voltage switchgear;Temperature increases;**Temperature measurement;Necessity.
1. Background research.
Because the high-voltage switchgear belongs to the closed structure, the heat dissipation performance is not good, and it is easy to accumulate a lot of heat, for the high-current switchgear such as low or busbar, when working at full load for a long time, when the heat rises sharply, it will cause damage to the electrical equipment, and the insulation is greatly reduced. Therefore, do a good job in the timely monitoring of the switch cabinet busbar, switch contacts and other parts, and do a good job of corresponding alarm measures. When the switchgear overheats due to excessive temperature, it will lead to fires and power outages, resulting in large economic losses, so it should be taken seriously.
2. The importance of high-voltage switchgear application temperature measurement technology.
The high-voltage switchgear is a very large electrical equipment in the power system, and the temperature is too high due to the internal closure, which causes the failure of the high-voltage switchgear, which is a common problem at present. Because the internal temperature of the switch cabinet is too high, it has a serious impact on the safe operation of the equipment, and because the temperature is too high is gradually rising, if the corresponding measures cannot be taken in time, the temperature will rise sharply, which will seriously damage the insulation performance and the service life of the electrical equipment. 2.2. Business collaboration needs to be deepened, and decentralized resources need to be further integrated.
Nowadays, the use of infrared temperature measurement technology is very common, and the potential safety hazards of the equipment can be found in time to deal with them in time, which can avoid greater losses. However, because the scope of application of infrared temperature measurement technology is the equipment exposed to the outside world, the high-voltage switchgear of the important equipment of the current power system cannot be detected or is prone to detect dead ends. The high-voltage switchgear is characterized by internal sealing, and there are a large number of joints, switch contacts and temperature indicators that cannot be seen from the outside, and other temperature measurement methods cannot be used to detect the existing fault problems at any time. Therefore, at present, the temperature monitoring of the joints and switch contacts inside the high-voltage switchgear is facing difficulties, and it is necessary to adopt first-class temperature measurement technology in order to better deal with it.
3. Causes of the temperature increase of the high-voltage switchgear.
3.1. Expansion of metal joints.
During the operation of the equipment, the copper bolt joints of the equipment will be plastically deformed due to the change of load current and temperature, which is closely related to the temperature. In practice, it has been found that when the temperature at the joint reaches more than 80 degrees Celsius, the joint metal will expand when heated, so there will be gaps on the contact surface and cause oxidation. Once the load current and temperature are reduced, the metal of the joint returns to its original position, but it cannot be directly contacted because of the oxide film on the surface. Each time the temperature increases, the contact resistance increases, which in turn causes the temperature to rise, and a cycle occurs.
3.2. The bolts of the connection part are too tight.
When the installer makes a conductor connection, it is usually believed that the bolt should be tightened enough. However, if the pressure of the nut is too large, because the strength of the material is not high enough, the excessive pressure will be applied, which will make the contact surface protrude, reduce the contact area, reduce the contact resistance, and reduce the conductive effect.
3.3. Other influencing factors.
Other influencing factors include: installation process problems, such as processing and connecting the bus, the contact surface of the bus is not properly treated, the surface is rough and not smooth, which will increase the contact area and increase the contact resistance and lead to heating. Due to the high pressure exposure in the switch cabinet and the small internal enclosed space, it is not possible to manually carry out inspections to monitor the temperature, and conventional temperature measurement methods cannot be used.
Wireless temperature measurement technology is to install a temperature sensor on the live connector and contact in the switch cabinet, measure the temperature of this part by measuring it, and upload it to the system wirelessly to give an alarm. Wireless temperature measurement technology can also be connected with the power automation system, managers can monitor temperature changes at any time in a distant place, and when the temperature is too high, the system alarm will be quickly dealt with to prevent more serious problems.
4**Advantages of temperature measurement technology.
*The insulation performance of the temperature measurement technology is very good, it can isolate the high voltage in the switchgear, and it can be installed in the high-voltage contact in the switchgear, so as to monitor the problem of the high-voltage contact at any time.
The temperature sensor in the temperature measurement technology can be directly installed on the live body, and the temperature can be directly measured on the equipment inside the cabinet and transmitted wirelessly.
*The temperature measurement technology has fewer leads, good insulation, and low cost.
5**Characteristics of temperature measurement technology.
The internal contact temperature of the high-voltage switchgear can be monitored at any time, and the temperature rise of the contact part can be grasped in time, and once the temperature is too high, the system will have an alarm. The temperature sensor is usually installed in the live contact part of the switch cabinet, and the temperature monitoring equipment of the switch cabinet sorts out the data transmitted back from the inside at any time, and then transmits the data to the industrial computer.
The wireless transmission mode will not affect the insulation of the switchgear, and the application is very convenient and the cost is low. Thanks to the special processing of the wireless sensor, various temperature data can be transmitted to the temperature monitor in time, and the monitoring signal is very accurate. The installation and maintenance of the wireless temperature measurement system are very safe and convenient, and will not interfere with the primary equipment. At the same time, due to the simple design, the installation process is very simple. After the temperature data is collected, it can be connected with the power system or with the local area network, so as to realize the automatic control of electric power.
6. Accuray temperature monitoring system solution.
6.1 Overview.
The temperature measuring device of electrical contact ** is suitable for the temperature monitoring of cable joints, circuit breaker contacts, knife switches, high-voltage cable intermediate heads, dry-type transformers, low-voltage and high-current equipment in high and low voltage switchgear, so as to prevent excessive contact resistance caused by oxidation, loosening, dust and other factors in the operation process and heat up to become a potential safety hazard, improve the safety guarantee of equipment, reflect the operation status of equipment in a timely, continuous and accurate manner, and reduce the equipment accident rate.
ACREL-2000T wireless temperature monitoring system communicates directly with the equipment in the spacer layer through RS 485 bus or Ethernet, and the system design follows the international standard MODBUS-RTU, MODBUS-TCP and other transmission protocols, which greatly improves the security, reliability and development. The system has the functions of remote signaling, telemetry, remote control, remote adjustment, remote setting, event alarm, curve, bar chart, report and user management, which can monitor the equipment operation status of the wireless temperature measurement system, realize rapid alarm response, and prevent serious failures.
6.2. Application place.
It is suitable for temperature monitoring of power equipment such as ubiquitous power Internet of things, steel mills, chemicals, cement, data, hospitals, airports, power plants, coal mines, substations and other power enterprises.
6.3. System structure.
6.4. System functions.
The ACREL-2000T is installed in the on-duty monitoring room, which can remotely monitor the operating temperature status of all switchgear in the system. The system has the following main functions:
6.4.1. Temperature display: display the real-time value of each temperature measurement point in the power distribution system, and can also realize remote viewing of data by computer, web, and mobile app.
6.4.2. Temperature Curve: View the temperature trend curve of each temperature measurement point.
6.4.3. Run the report: query and print the temperature data of each temperature measurement point.
6.4.4. Real-time alarm: The system can send an alarm for the abnormal temperature of each temperature measurement point. The system has a real-time alarm function, which can issue alarms for all events, such as pop-up windows, alarms, etc., and can also push alarm messages to the APP to remind the personnel on duty in time.
6.4.5. Historical event query: It can store and manage event records such as temperature overruns, which is convenient for users to trace the history of system events and alarms, query statistics, accident analysis, etc.