Protection distance of surge protective devices in low voltage distribution systems

Protection distance of surge protective devices (SPDs) is an important problem in designing a good location scheme of SPDs in low voltage distribution systems for protecting electrical equipments against overvoltage caused by lightning stroke. The simplified lumped-parameter circuit model and the circuit method were used to study the protection distance problem of SPDs. The analytical solutions of the load voltage and generale quations of the protection distance of SPDs under different load conditions were given. Simulation results of examples proved the validity of the proposed analytical method.