The Optical Properties Analysis Of Sf₆ And The Development Of Its Leak Detecting System

SF6 has been widely used in power system such as high-voltage circuit breakers, transformers etc. for its excellent insulative and arc extinguishable characteristics. But these characteristics will change when SF6 leaks; it would bring problems to equipment safety and take dangerous to operator. "Working Regulation of Electrical Safety" prescribes that SF6 and O2 detecting device must be installed in high voltage substations.In the early days, SOAP water and handheld leak detector used to detect SF6 leaks were not online testing methods. The conclusion is made by user and the result is also not accurate. From the late 1990s to the beginning of this century, new online detecting methods such as UV ionization, high-frequency oscillatory non-electrode ionization, e-capturing, platinum hot electron emission and corona discharge have been gradually developed. But some poor performance is still found such as difficulty in finding leak position; trouble in insufficient quantitative testing and detecting errors caused by environmental changes. Laser Imager GasVueTG230 which is developed by ERPI Co. of American can locate the specific parts of the leak position in a relatively long distance, but the device is still not suitable for SF6 leak detecting. The first reason is its clumpsy; the second is that the imaging range must be larger than 3 meters in order to get a better image resolution; the third is that the leak point without background cannot be checked out by this device.This paper first points out the shortage of current studies on SF6 detection technology, and at the same time analyzes the characteristics that the CO2 laser can be largely absorbed by SF6 gas. The conclusion of using a new SF6 leak detecting system applying CO2 laser is drawn. The system design scheme is proposed. The design of remote monitoring center, data control center, optical and electrical control system, SF6 optical analysis system, temperature and humidity testing terminal, derivatives such as H2S and SO2 concentration measurement terminal are described in detail. The system avoids the shortage of device aging fast and high false alarm rate which stay on the old system. It can on-line detect environmental parameters in real time, the detect result can also be comprehensively analyzed to make early warning. It is a new generation of electricity safety monitoring system.Finally, this paper summarizes the research contents and puts forward a further study direction on the topic.