ABSTRACT
Protection of power systems from lightning-related damage and faults is crucial to maintaining adequate power quality, reliability, and controlling damage costs to the utility system. This chapter focuses on the factors that impact the lightning performance of power distribution systems, and provides background on the characteristics of lightning, methods for calculating lightning flashover rates, and guidelines in the application of lightning protection equipment. One lightning flash may cause multiple flashovers and equipment failures. Lightning causes most damage by directly striking an overhead phase wire and injecting an enormous current surge that creates a very large voltage. Lightning is the electric breakdown of air from high electric fields generated when the electric charge separates within a cloud. While the downward negative flash is the most common, other types of cloud-to-ground lightning occur. When lightning injects surge currents into power lines, they move down the conductors as traveling waves.
