关键词: 500kV输电线路, 雷电过电压, 一体化模型, 冲击接地电阻值

Abstract: Lightning accident often occurs on 500kV transmission line, which influences on safe operation seriously. To explore the relationship between lightning overvoltage and impulse grounding resistance, we establish an integrated model. According to field-circuit coupled method, a transmission line-tower-grounding grid was setting up. The influence of earth resistivity, lightning current wave front time and amplitude was study. The experimental equations about lightning overvoltages were developed in the meantime. We established an expression of the relationship between lightning overvoltage and impulse grounding resistance. Study shows that the decrease of lightning current wave front and increase of earth resistivity would increase the value of impact grounding resistance and lightning overvoltage. Impact grounding resistance has no relationship to lightning current amplitude but lightning overvoltage has a variation of direct proportion with amplitude. We should consider the effectively length of grounding grid when design grounding grid. This research can provide guidance on lightning protection of 500kV transmission line.

Key words: 500kV transmission line, lightning overvoltage, integrated model, impulse grounding resistance