Investigation on lightning surge current flows from residential solar power system to distribution lines and watt-hour meters

Abstract

In recent years, residential solar power systems have been increasingly introduced at a rapid pace. To date, lightning surge currents have been considered to intrude into houses via four kinds of routes, power lines, communication wires, antenna wires, and ground wires respectively. However, if a residential solar power system is installed in a house, an additional lightning surge current will eventually come from the residential solar power system. On the other hand, it is thought likely that more electronic watt-hour meters, or so-called smart meters, will be installed in future. Since electronic watt-hour meters may potentially be more vulnerable to lightning compared to conventional mechanical watt-hour meters, more attention must be paid to the influence of lightning on electronic watt-hour meters. In this paper, lightning impulse tests were conducted for houses where a solar power system was installed. To study the influence of lightning on an electronic watt-hour meter, it is crucial to clarify the condition of the lightning surge current flowing from a residential solar power system hit by a lightning stroke. During these tests, the propagation condition of the lightning surge current flowing from the residential solar power system through the distribution line and the watt-hour meter was studied.