A Computation Method of Voltages across Insulator Strings considering the Effect of Lightning Strokes

Abstract

This paper proposes a method to compute voltages across insulator strings considering the effect of lightning strokes. Line voltages are handled as lightning-induced voltages on multiconductor systems with transition points caused by inclined lightning strokes. It is easy to solve line equations derived from Maxwell's equations using a difference method. However, it is difficult to obtain voltages and currents at the transition points consisting of various elements (lumped and distributed parameter circuits, arresters, gaps, and so on). Then, the proposed method uses Dommel method, which can easily and stably handle a large electric network, in order to solve the circuits of the transition points with equivalent sources and backward impedances. A program developed by the proposed method is based on the Electromagnetic Transients Program (EMTP), thus, input data is almost compatible with that of the EMTP. The calculated values by the program agree well with the experimental results using a scale model.