ALGORITHMS FOR CALCULATION OF LIGHTNING-INDUCED VOLTAGES ON DISTRIBUTION LINES

This paper reviews the uncertainties involved in evaluating induced voltage lightning performance of distribution lines, and outlines two algorithms to facilitate computer simulation. These are: 1. A simplified surge impedance model of each wire section of the line, permitting the coupled electromagnetic fields to be replaced by simple algebraically computed forward-backward (FB) current pairs, easily processed by computer to handle current reflections and refractions from transformers, arresters, taps and other discontinuities. 2. An algorithm for distribution line induced voltage lightning performance calculations that integrates between a striking distance curve and a critical flashover-distance curve. These algorithms have been successfully embedded in a comprehensive digital line performance program, and results from this program will be provided in a companion paper.