Study of Power Equipment Trouble Caused by Lightning in Traction Substation

At a traction substation in JR East, impact pressure relays of traction transformers and auxiliary relays related to these relays in control panel were broken. As a result of field surveys such as lightning indicator on the power transmission towers and trace of flashover on insulators separating overhead ground wire of substation from that of power transmission line, it was confirmed that lightning surge had invaded in this substation from power transmission line of power utility company. However, it was not possible to understand the process by which this trouble occurred. In this paper, we introduce an estimated processes that transformer protective relays were broken through various surveys. In addition, since the same trouble occurred in the next year at a different substation, most probable cause that considered from the result of a lightning impulse injection test was shown.