Field Tests of Low-Side Switching of EHV Transmission Line

Over 400 low-side switching operations energizing EHV transmission lines were carried out by the Department of Water and Power, City of Los Angeles. These extensive field tests included measurement of the magnitude and range of overvoltages produced under various system conditions and with different values of preinsertion resistors. The purpose of the investigation was to gain first-hand field experience with low-side switching operation and to confirm the validity of Transient Network Analyzer (TNA) studies conducted with similar circuit parameters.