GAS-ANALYSIS BY INFRARED-SPECTROSCOPY AS A TOOL FOR ELECTRICAL FAULT DIAGNOSTICS IN SF6 INSULATED EQUIPMENT

Infrared spectroscopy shows an enormous potential for the analysis of by-products generated from electrical discharges in sulfur-hexafluorid e (SF6) insulated equipment. Since by-product composition can be relat ed to the fault genesis (are, partial discharge or corona), the analys is of contaminated SF6 provides a valuable diagnostic tool. The IR-spe ctrometric results from discharge experiments are presented, carried o ut with the application of SF6 pressures around 300 kPa and an alterna ting voltage up to 30 kV. Under the discharge conditions used, the mai n by-products found are the sulfuroxyfluorides SOF4 and SO2F2 with con centrations correlated to the discharge time. Due to its toxicity, spe cial attention is also paid to S2F10 The experimental conditions and p ractical aspects for reliable quantitative analysis of reactive specie s are discussed.