OPTICAL DISCHARGE DETECTION IN SF6-INSULATED SYSTEMS

It is well known that corona discharges can occur in SF6-filled compressed gas insulated systems (GIS) due to the electrode and insulator surface imperfections and the presence of free conducting particles. If such discharges are allowed to continue, these can lead to ultimate failure of the insulation. Therefore an early detection and consequent prevention of such discharges is highly desirable. This paper describes an optoelectronic system for detecting and locating corona discharges in SF6 filled GIS. The system consists of optical fiber links, photomultiplier light detectors, operational amplifier and a computer-based data collection system. Various factors which can influence the optical discharge detection sensitivity are investigated. It is shown that an optical system can detect discharges which are located even in the hidden areas in GIS. The optically measured discharge onset voltages are verified by using the conventional electrical discharge detection techniques. © 1990 IEEE