Research on the Influence of Overhead Ground Wire Grounding on Lightning Protection

Based on the lightning data, faults and lightning protection demonstration projects measured on a 10 kV distribution network line in a county in Yunnan, the lightning protection of overhead ground lines was analyzed. After analysis, it is found that the amplitude of the overhead ground wire from the coupled induced lightning source is the best. This paper further studies that the refraction and reflection of the induced voltage wave is the root cause of the oscillating attenuation of the induced overvoltage wave. The grounding point greatly reduces the amplitude of the induced lightning voltage within a certain range. Through simulation analysis combined with actual measurement analysis, it is found that the voltage wave delay time of the grounding point is greater than the overvoltage wave front time, and the overhead ground wire will fail; the grounding distance of the overhead ground wire is very important to suppress the induced lightning wave. It is recommended to carry out grounding transformation at each level of the tower Optimal.