Protection of MV and LV networks against lightning – Part 1: Common topics

This brochure presents basic information and principles related to lightning protection of Medium Voltage (MV) and (LV) networks. The present material constitutes the first part of a 3-part guide. Parts 2 and 3, to be published later, will deal specifically with the application to MV (Part 2) and LV (Part 3) networks. This part provides first a survey of different sources of overvoltages, as well as a review of the most widely accepted and well established methods of evaluating the expected rate of direct lightning strokes and induced lightning overvoltages. The document describes in addition the characteristics of lightning overvoltages, general characteristics of surge protective devices, and earthing systems.