抄録
Two methods currently exist to evaluate degradations in arresters in Shinkansen substations. One method uses a surge current counter device to count the number of strokes of lightning. However, surge current counter devices sometimes pick up small switching surge of changeover switches, which are not deterioration to the arrester. The other method is to measure normal leakage current of arrester. This method though is potentially unreliable because the leakage current is strongly affected by the feeding voltage harmonics. A deterioration diagnosis device was thus designed with functions to suppress unwanted small surge current counts and provide accurate measurements of the leakage current in the target arrester. This paper describes various field measurement results, the principle underlying the developed deterioration diagnosis device and a new method for extracting the resistive current in the arrester from the overall measured leakage current.
