The Lightning Protection Research Of 35kV Weiyu Line

In the substation of Mianyang, a majority of 35kV lines power the military plants for scientific research or manufacture. For the line corridor was a mountainous area with complex landform and high soil resistivity, the line lightning protection measure was weak. And for history reasons some 35kV lines were not all spanned with lightning conductor. The operation data in recent years reveals that the repeatedly accidents which caused by lightning striking 35kV lines heavily affected the safety of our manufacture. So it was worth studying synthetic lightning protection measures on demonstration of the situation of the Mianyan Bureau's 35kV lines.On the basis of collecting and summarizing the lightning protection data of our 35kV lines, this paper mainly analyzed the lightning protection status of 35kV line. With the demonstration of 35kV line of Youxian substation, it built a numeral value calculation model of on-line data of each pole. In terms of many factors, it studied on how to improve lightning withstand level, especially on how to use MOA economically and reasonably, and on the synthetic measures to decrease the lightning tripping outrage.It is found that, for the specialty of our 35kV lines, we should adopt synthetic lightning protection measures of power lines as the traditional measure could hardly keep up with the lightning protection requirement for its low line lightning protection level, high stripping outrage and bad maintenance. These measures include installation of lightning lines, decrease of the tower grounding resistance as far as possible, the reasonable use of arc suppressing coils and adoption of arresters. The investigation reveals that, the adoption of MOA on segments of 35kV Weiyu lines apt to lighting strike would improve the lightning withstand level to 2-4 times, and would heavily reduce the stripping outrage. This paper also discussed the influence of variation of tower grounding resistance or distance between towers to the effect of MOA. It also put forward feasible suggestion and scheme for our lightning protection work.