Protection against Lightning Surge Invasion into Secondary System of Substation
Dai Zi-qin · Insulators and Surge Arresters · 2008
Path of lightning surge invasion into secondary system of substation was described. By means of lightning surge invasion simulation it is obtained that at lightning strike current amplitude reaching 80 kA, the voltage amplitude of 193.983 285 V coupled to secondary system from the substation transformer itself, which is far beyond the withstand voltage level of installations of secondary system, leading to their failure. The triple protection measures for secondary system is proposed as follows: lightning protection of LV supply, prevention from inductive surge invasion through signal and control conductors and improvement of ground potential distribution.