Study on Lightning Withstand Level and Protection Measures of 10kV Distribution Lines

Distribution line is an important part of power system, it is very important to improve the lightning protection performance of distribution lines effectively to ensure the stability and reliability of power supply. The lightning protection of distribution lines are mainly focused on lightning withstand level calculation, lightning tripping rate calculation, lightning protection performance evaluation and comprehensive lightning protection measures. The paper mainly studies the lightning withstand level and comprehensive lightning protection measures of 10kV distribution lines. Firstly, the actual lightning protection status of the 10kV distribution lines in the Yangjiang area is analyzed and the affect of lightning protection measures are verified based on the statistical results of the lightning failure status, the investigation of the topography. Secondly, based on the electromagnetic transient numerical simulation program PSCAD/EMTDC, the accurate simulation analysis model of lightning overvoltage in distribution lines is established. Thirdly, the influence of line arresters and grounding resistance on lightning withstand level are studied. Finally, the different line arresters arrangement schemes are proposed. The results show that the lightning withstand level of the direct striking and back flashover of distribution line are both very low, at several kilo Amps, and the withstand level relates to the insulator and grounding resistance. The lightning withstand level will be increased by 45% when a set of line arresters are installed every 4 base towers. The protection effect of the line arresters decreases with the increase of the grounding resistance.