Structure-Dominated Failure of Surge Arresters by Successive Impulses

Abstract

This paper investigates the influence of structure on the failure of full-scale metal–oxide arresters under successive lightning impulses. Typical structures of arresters are compared by simulation and experiment. With a finite-element model for the electrical-thermal multiple-field analysis, the thermal characteristics of typical structures of full-scale arresters under successive impulses are obtained. It is revealed that the filled solid insulation can contribute to more radial heat dissipation than filled gas. Experimentally, two full-scale arresters with different structures were exposed to successive nominal lightning impulses until failure, and it is found that the impulse failures of arresters are dominated by the structure and component. Surface flashover is the most common destruction for the varistor column. The cylinder type of varistors is suggested rather than hollow type, and the sleeve for position constraint of the cylinder varistor column should not be organic in order to avoid carbonization by arc discharge. It is found that the metallic spacers can contribute to sprayed-electrode protection, arc extinction, and heat dissipation. Based on the aforementioned results, an advanced arrester with structure optimization is proposed.