Protection of UHV Substations and Transmission Lines against Lightning

Abstract

In combination with characteristics of the lightning performance of UHV power transmission lines and on analysing the experiences and lessons relating excessively high lightning trip-out rate on 1000 kV transmission lines in Japan. The minimization of ground wire shied angle along with distance of the gap with a proper length is an important step for shielding failure trip-out in China. So, we should pay attention to the shielding failure flashover of the lines in mountain area in that place. Lightning trip-out faults has by no means arisen in China’s UHV transmission lines so, it displays a noble lightning act. The paper also describes the methods and principles used for measuring lighting inrush overvoltage to UHV substation in China and also tells that the concurrent adoption of measures of both reducing the maximum reducing current of ground wire shield angle and distance of the gap with an definite length is an important measure for reducing the shielding failure trip-out rate of 1000 kV transmission lines. Consequently, to pay courtesy to the shielding failure flashover of the outlines in mountain areas with higher inclination of ground along the lines are obligatory. Here, we introduce the ground wire shield angles used for UHV transmission lines in plain and mountainous areas in China. Lightning trip-out faults have never occurred up to the present time in China’s UHV transmission lines, thus it shows a good lightning performance.

Keywords: UHV, power transmission line, substation, lightning, intruding wave, overvoltage, 1000 kV