Design And Practice Of Bazhong 500kv Transformer Substation SF₆ Gas Moisture Content On-line Monitoring System

With the development of China Power System, especially the rapid development of EHV and UHV system, in the modern construction of substation system, the high-voltage electrical equipment insulation medium and arc quenching medium requirements more and more high. In this case, the SF6 gas as insulation and arc quenching medium voltage equipment is applied more and more widely, and the SF6 GIS has the advantages of small occupied area, convenient installation, reliable operation, simple maintenance and other advantages, has become the most commonly used equipment in the construction of the current substation. But the SF6 GIS gas equipment in micro water content exceeding the qualified standard, will be on the equipment mechanical and electrical properties are affected, will affect the equipment, power grid and operating personnel safety.GIS online monitoring technology can be real-time monitoring of the running state of the equipment, it also can overhaul the equipment in time to avoid failures. It also can establish equipment performance assessment basis, so as to improve equipment availability. Through on-line monitoring equipment can be used for evaluation of the performance, so as to adjust the use, extend the repair cycle, improve equipment availability, reducing unnecessary maintenance and improve the economic benefit.Based on the effects of temperature, pressure and humidity of gas are analyzed, characteristics extraction of online monitoring system monitoring. The performance of the temperature sensor, pressure sensor and dew point transmitter is analyzed. At the same time, combined with the specific requirements for the site, choose the types and models of sensors and transmitters.According to the working principle of the on-line monitoring system, the hardware structure is designed. In the main control building of the substation, the server is set up, and the server is communicating with the field monitor. On-line monitoring instrument collecting the SF6 gas pressure, temperature and dew point value in GIS in time connect the server with the CAN bus.If you want to realize the on-line monitoring system is running well, must also pay attention to the quality process control during the installation process. In the end, the system implements the substation site on-line monitoring of GIS equipment, and can query and analyze the data. At present, the system works well in the 500 kV HGIS equipment of Bazhong 500 kV substation.