Life management of GIS based on deterioration diagnosis of aged GIS

Gas Insulated Switchgear (GIS) is composed of several components such as circuit breaker, disconnecting switch, lightning arrester and so on. Although life-time of each component is evaluated, however there are few examinations on the whole of GIS. This time, we have overhauled and investigated all the components of the 77 kV outdoor type GIS at Moriyama Substation and Tsukioka-cho Substation of Chubu Electric Power Co Inc. which have been in service for 31 years and 30 years respectively. Then, we analyzed the deterioration progress and its process of GIS from the results of overhaul together with our technical experiences. Therefore, we could obtain very useful deterioration diagnostic data and identify the parts affecting the GIS lifetime. Based on these results, we have summarized external diagnostic and repair technologies, which are effective for GIS life management, and items to be newly reflected to design.