Abstract Shielding failure rate is an important parameter to calculate lightning withstands level. Traditional method estimated shielding failure rate by mean value of height about conductor wires or shielding wires. Some inaccuracies existed and real situation was difficult to express. Traditional method is extended in this paper. The new method is presented based on three-dimensional bend to calculate shielding failure rate of transmission lines. This method obtains formula with the height of the conduct wires as variable and shows change rules of shielding failure rate with change of distance between the section vertical to transmission lines and tower. By means of integral to this formula, the formula about shielding failure rate of the whole span spatial model is obtained. Analysis in this paper is based on electro-geometric model(EGM), but also compatible for leader propagation model (LPM) or other method. Formula of shielding failure rate to different method can be obtained. Because of the method presented in this paper considering three-dimensional space, data from which are closer to real situation comparing with traditional EGM. It can be useful to improve precision about calculating lightning withstands level of transmission lines.
Li Ruifang,Wu Guangning,Cao Xiaobin等. Three-Dimensional Calculation Method on Shielding Failure Rate of Transmission Lines[J]. Transactions of China Electrotechnical Society, 2009, 24(10): 134-138.