Monitoring The Pressure, Temperature And Content Of Micro-water Of SF₆ Gas And Remote Querying

There are two main parameters in monitoring the status of SF6 gas, one is leakiness, and the other is water vapor content. Because pressure gauge and density relay is adopted widely, traditional method of leakiness inspection can't compensate the effect of temperature to pressure and has no enough precision and reliability. Although it is very complex to monitor the water vapor content, the measured result can't reflect the status of SF6 gas exactly.In this dissertation, the digital solving theory and processing are introduced in detail, in which the gas temperature and pressure are inputted to SF6 gas status equation and density of SF6 gas can be obtained, and then it is easy to calculate the pressure of SF6 gas in 20℃. The method compensates the effect of temperature to pressure and the judgment to leakiness of gas can be very direct and exact.Before introducing the new method of monitoring water vapor content, the SF6 gas Status and industry Standard in power system about the water vapor content are discussed in this dissertation, in which Some questions are proposed and a new Control Standard is put forward. The new method proposes that take the relative humidity of gas as the parameter of measurement and consider the effect of the pressure and temperature to the ppm of content of micro-water. It eliminates the effect of temperature to ppm value through renormalization; therefore, it will reflect the absolute amount of hydrosphere through adopting absolute hydrosphere really.This dissertation puts high premium on designing and developing a SF6 gas-monitoring instrument. The device has the characteristics as follows: In the respect of the monitoring function, the humidity, temperature and pressure of SF6 gas can be obtained by sensors. An exact judgment on gas leakiness can be drawn through calculating the density and micro-water of gas. In the respect of the malfunction diagnosing, a kind of three-dimension mode is proposed to get more general and accurate result by making a comparison between the monitoring data and criterion, its own historical data and the data gotten with another same-type equipment. In the respect of designing and developing the device, 80C196KC is adopted as the key module of the hardware. In additions, a method of modular programming is used in the software design. The monitoring result can be shown not only by computer which connect with single chip, but also be visited by Internet. The experimental result shows that the instrument has very good performance.