Abstract
Surge arresters which installed at customer's facilities and distribution linesare often damaged by winter lightning in mountainous areas facing the Sea of Japan. Therefore we have observed the lightning performance at a mountainous area, since 1998, in order to verify the effective lightning protection methods for customer's facilities and distribution lines. Based on the observation data and analysis results using the EMTP, we propose the effective lightning protection methods for customer's facilities.
(1) When grounding resistance of a customer'sfacility is less than 10 Ω, lowering the grounding resistance is one of the effective lightning protection methods for preventing a customer's arrester failure.
(2) It is effective for preventing a customer's arrester failure that grounding of a customer's facility is connected with an overhead ground wire of a distribution line through an earth wire, and it dose not increase a failure probability of a distribution arrester.
