Performance Analysis of Lightning Surge Mitigation in Distribution Networks Using Optimal Surge Arrester

Abstract

Lightning surge interaction in distribution networks can produce severe fast-front transient overvoltages, insulation stress, back-flashover, and transformer terminal voltage escalation. This study evaluates the effectiveness of surge arrester placement in a 33 kV radial distribution network using PSCAD/EMTDC electromagnetic transient simulation. A total of 27 operating scenarios were analysed by varying three key parameters: lightning strike type, namely direct strike and lightning-induced electromagnetic coupling; insulation condition, namely normal operation and back-flashover operation; and surge arrester configuration, namely unprotected network, substation-based arrester placement at Site A, and line-corridor arrester placement at Site B. The simulation results show that the unprotected network is highly vulnerable, with direct lightning strikes producing voltage spikes up to 8.65 MV. Conventional arrester placement at the substation entrance effectively reduces the transformer terminal overvoltage to 464.792 kV under normal operation; however, during back-flashover, this configuration causes a ground potential rise (GPR) anomaly, increasing the transformer terminal voltage to 997.164 kV. In comparison, the proposed Site B placement provides better overall performance by eliminating the substation GPR effect, reducing the peak voltage to 719.910 kV, and achieving the fastest transient recovery with a settling time of $40.870 \mu \mathrm{s}$. The findings indicate that corridor-based surge arrester placement offers a more effective protection strategy than conventional substation-only placement by improving voltage clamping, reducing insulation stress, and enhancing the transient stability of the distribution network.