Research on lightning protection of overhead power distribution lines

There are two major protective methods against lightning outages on overhead distribution lines. One is a surge arrester, and the other is an overhead ground wire. The surge arresters have rather constant effect regardless of the cause of the lightning outage. On the other hand, the effect of an overhead ground wire is quite different in two major causes, the direct lightning hit and the induced overvoltage. It is sufficient to provide surge arresters with an interval of 300 m for protection against the induced overvoltage caused by the nearby lightning stroke. Use of an overhead ground wire together with surge arresters is effective for lightning protection against the direct lightning hit to a distribution line. Puncture of surge arresters is the popular outage when the outage caused by the insulation break decreases sufficiently. Also, the existence of nearby trees leads to the line break due to the side flash from a tree. Advanced lightning protection equipment with ZnO arrester components is popular in Japan. Modeling of a pole transformer and application of an electromagnetic analysis method, such as FDTD method, to surge phenomena is considerably advanced.