Deterioration and its Improvement of Magnetic Blow Out Type Surge Arresters with Series Gaps

Abstract

This paper describes deterioration characteristics of 266kV magnetic blow out type surge arrester with series gaps having actual about 30 years operation, and metal oxide surge arrester as its improvement. Main deteriorated components of surge arresters are extinguished chambers closed in series gaps, grading resistors for series gaps and covers for sealing. In case of deterioration of covers, water contents immerse into porcelain containers. Power frequency sparkover voltage decreases gradually. Finally, surge arresters are possible to fail down at normal operating voltage. It is important to seal covers with gaskets between porcelain fittings and ceramics porcelains.