Full-process evaluation of lightning protection for multi-circuit 10 kV distribution lines

Abstract

Multi-circuit overhead distribution lines are increasingly used in medium voltage networks because they improve corridor utilization and reduce construction cost. However, their compact phase arrangement, shared pole structure, relatively low insulation level, and grounding constraints make them vulnerable to both direct and induced lightning overvoltages. This paper proposes a full-process lightning protection performance evaluation method for multi-circuit 10 kV distribution lines. The lightning process is represented by leader attachment, return stroke, and post-stroke current stages, and the corresponding direct lightning and induced lightning regions are identified using an electrogeometric model. An ATP-EMTP based electromagnetic transient model is established by integrating lightning current injection, tower surge impedance, phase conductor coupling, grounding resistance, insulator flashover criterion, and arrester operation. Parametric simulations are carried out under different stroke locations, lightning current amplitudes, insulation levels, and tower grounding resistances. The results show that grounding resistance and phase height strongly affect the backflashover risk, while surge arrester placement and insulation coordination significantly reduce the maximum overvoltage. The proposed method provides a basis for differentiated lightning protection design of multi-circuit distribution lines.