Effective design of a two-stage surge protective device for AC low voltage system protection

This study describes a useful technique for the optimal design of a two-stage surge protective device in the mitigation of overvoltage in low-voltage AC power systems. Two metal oxide varistors (MOVs) and a single inductor are used to form the protection circuit. A genetic algorithm based on MATLAB software is applied for the determination of the proper inductance. The conditional optimization is set to minimize the overvoltage generated by a combination wave generator. Meanwhile, the proposed SPD does not affect the voltage drop in the power frequency voltage (50 Hz). In the simulation process, the current-voltage (I-V) characteristics of SPDs are collected from the manufacturer’s datasheet. The simulation results with the proposed circuit are confirmed by those calculated by ATP/EMTP software. Experiments for validation of the proposed approach were also carried out in a high-voltage laboratory to check the performance of over-voltage mitigation. According to the experimental and computational results, the proposed circuit performs well in terms of over-voltage mitigation. It has been confirmed that the presented approach is attractive for overvoltage mitigation in low-voltage AC power systems.