Overhead surge protection of low-voltage systems connected to line

A procedure of choosing the appropriate surge protective device for low-voltage systems is presented. For typical surge protection application an appropriate EMTP model is devised. The energy overload is calculated for a surge protective device following a simulation of the lightning effect. In this way it is possible to determine a required class for a surge protective device in question. The procedure is tested on some typical overhead low-voltage network. According to calculation results and very good service experiences, Class II surge protective devices can be adequately used for service entrance of buildings.