Design of Lightning and Surge Protection System for Air Insulated Substation

Abstract

Power transmission lines when subjected to lightning and switching surges, poses complex insulation engineering problems. Design of overhead power lines with an acceptable level of protection for lightning in the area with high density of lightning ashes, and high specific resistively of the soil could be a challenging task. So lightning protection system must be placed at the substation. The purpose is to understand the methods and measures used to reduce the negative effects of lightning strikes in a substation. The outcome of lightning strikes to a substation can be either direct or indirect. Method of lightning protection used in the substation must be designed to protect personnel and equipment from the dangers arising from lightning strikes. The main protection for lightning strike is lightning masts and overhead earth wires. Lightning masts are more preferable than overhead earth wires to reduce the overall profile of the substation. Overhead earth wire must be used when lightning masts are not possible and sufficient. In this project, the main goal is to design and calculate the optimal number of earth wires as per standard practices and consider the option of lightning mast/tower arrangement for air insulated substations. Lightning protection system is to be designed with earth wires at different angles to reduce the effects of lightning strikes in the substation.