Research on Resonance Overvoltage of EHV Transmission Lines Caused by Lightning Strike

Abstract

This paper studies the mechanism and influencing factors of resonance overvoltage of EHV transmission lines caused by lightning. By analyzing the time domain steady state of the simplified resonance circuit, the physical mechanism of resonance is revealed. The characteristics of resonance transient process and overvoltage waveform are analyzed by using electromagnetic transient simulation. The main influencing factors of overvoltage amplitude are also studied. The results show that: 1) During uneven open-phase conditions, resonant circuit involving shunt inductors and line equivalent capacitor obtains energy from lightning strikes, which may lead to resonance. 2) the transient process of resonance can be divided into three stages, including lightning stage, lightning-resonance conversion stage and steady-state resonance stage, among which the voltage of the first two stages are higher; 3) the lightning strike time, lightning current parameters and subsequent lightning strike affect on the overvoltage amplitude, which leads to the random amplitude in overvoltage.