Paper Title
Expert System to Diagnose Incipient Fautls in Gas Indsulated Substations

Abstract
The increasing application of SF6 as an insulating gas has led to many studies on SF6 decomposition in gas-insulated equipment and the developing GIS (gas insulated substations) systems. In the presence- of an electric arc, spark or corona, SF6 decomposes to a wide variety of chemically active products which possess completely different properties from SF6. The accumulation of these decomposition products in the equipment has caused concerns regarding personnel safety and material compatibility problems. This paper discusses SF6 decomposition relating to the operation of gas insulated switchgears, gas-insulated transmission lines, and electrostatic accelerators, by-products and their formation rates in various modes of electrical discharges. In particular, the influence of discharge energies and impurities on the formation of SOF2and S02F2, the two dominant stable by-products, is discussed. The effects of the by-products on personnel safety and equipment dielectric integrity are presented. The application ofSF6 gas analysis as a tool for diagnosing the internal condition of gas-insulated equipment is assessed. A tool is developed in Matlab for the incipient detection of decomposition to take safety measures Keywords- SF6 Gas, By-Products, Safety Measures, Developed Tool In Matlab