Surge Impact Characteristics of Low-Voltage Overhead Lines Caused by Natural Lightning

The paper presents an analysis of the residual voltage characteristics of surge protective devices (SPDs) made of zinc oxide on low-voltage overhead distribution lines. The study observed 65 natural lightning events and found that the geometric mean peak value of the SPDs' residual voltage was 767.6 V, with a geometric mean duration of 97.3 μs. The peak current flowing through the SPDs had a geometric mean of 6.4 A, and the SPDs absorbed an average of 0.2 J of energy. Based on the distinct processes of return stroke and the superimposed M component, the surge impacting the SPD can be categorized into three types. The currents flowing through type A and type B SPDs are essentially identical, but they differ in terms of residual voltage waveform. The main surge impact occurs during the return stroke process. Type C is distinct from the other two types: The surge impact expands through the superposition of the M component during the return stroke, resulting in approximately twice the duration of residual voltage and peak current flowing through the SPD compared to the other types. Additionally, in type C, the SPD absorbs about 5.8 times more energy. An analysis of the surge energy corresponding to the first and subsequent return strokes revealed that the surge energy generated by the first return stroke was approximately 2.5 times greater than that of the subsequent return stroke. © 2025 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.