Shielding failure analysis of 132 kV transmission line shielded by surge arresters associated with multiple strokes lightning

Abstract

Analysis of shielding failure is carried out to observe flashover of insulators parallel with phase conductors of a transmission line associated with a lightning strike on phase conductor. Peak current of different magnitude have been used to represent the multiple strokes lightning (MSL). This paper aims to simulate the worst case due to transmission shielding failure with three direct strikes to a line phase conductor of magnitudes 25 kA, 35kA, 50kA, 65 kA and 80kA per strike respectively. Insulators where flashover had occurred with respect to MSL were identified. Installation of an arrester on a phase insulator where a flashover has occurred proven to be useful mitigation technique thatch could prevent flashover of the insulator and also improves lighnting performance of the line.