Lightning-induced overvoltage on overhead distribution line via hybrid MTL-PEEC method

Abstract

Transient simulation are more economical and adaptable means of studying lightning overvoltage for overhead distribution line system compared to experiments. A hybrid multi-transmission-line (MTL)-partial element equivalent circuit (PEEC) method proposed for lightning-induced electromagnetic pulse (LEMP) simulation is verified using the rocket-triggered experimental results under a more complex line configuration for the first time. This method can improve computational efficiency while ensuring calculation accuracy. The agreement between experimental and simulation results further validates the adaptability and accuracy of the proposed method, which is adopted to calculate the LEMP on the extended double-circuit parallel unequal length line. The effects of various factors, such as the strike-point location, the amplitude and waveform of the lightning current, the line shape and length on the amplitude of overvoltage and pole flashover along the line are discussed. For double-circuit distribution lines, when lightning strikes the ground in front of centre of circuit I, the three-phase voltage waveforms are similar, all of which are negative or bipolar oscillation waves. The closer the lightning strike point is to the line, the greater the amplitude of the lightning current, and the voltage waveform develops towards a bipolar waveform, but the main peak remains negative. As the amplitude of lightning current increases, the maximum lightning-induced voltage amplitude along the line increases. The LEMP caused by the subsequent return-stroke current is always greater than that caused by the first return-stroke current. When the grounding resistance increases, the maximum voltage peak amplitude along the line remains unchanged.