Partial Discharge and its Application to Gas Insulated Switchgear

Higher reliability is demanded with gas insulated apparatuses such as gas insulated switchgear (GIS) and gas insulated circuit breaker (GCB). Since gas insulated apparatuses are sealed structures, it is difficult to find internal defects from outside. Therefore, development of preventive maintenance techniques is necessary for GIS to prevent failures and to detect defects early. Detection of partial discharge (PD) is one effective means for this purpose1. PD signals in SF6, especially, have radio frequency components of high and wide bandwidth in the UHF region, which is more than a few hundred MHz. We have developed a UHF based GIS diagnostic system, which includes a neural network for improved and accurate fault assessment2.