Abstract
Overvoltage induced by surge currents due to thunderstorm lightnings causes harmful breakdown troubles of CATV communication equipment installed in and with power distribution systems. In this paper, the origin and natures of surge currents, their invading route into the system, and the system components such as earth impedances affecting over voltages are studied. Transient analyses are then performed using an equivalent circuit to evaluate over voltages. Application of the obtained results to the field fault data of communication equipment and possible protection method of them are discussed.
