Simulation Study Of Lightning Protection For Transmission Lines Based On PSCAD

35kV overhead transmission line plays an important role in distribution network in China. While most of it went through the desert or mountains, the probability of being struck by lightning is much greater than that of other power equipments. In addition, the insulation level of it is relatively low, once the lightning occurs, it is easy to cause circuit components damage and even line trip, which will destruct power supply. Therefore, systematic analysis for the characteristic of 35 kV overhead line and adopting perfect lightning protection measures will be of great significance to improve the reliability of power supply system.In this paper, through the field investigation and statistics for the actual situation of lightning strike on 35 kV overhead transmission line in a certain area, the simulation model of transmission line by PSCAD-EMTDC software is established for analysis the influence of grounding resistance, grounding wire and lightning arrester on lightning withstand level of transmission line.Firstly, compares the lightning withstand level and lightning trip out rate under the condition of single and double lightning conductor by calculating. Calculated result shows that, erecting the double lightning line can effectively improve the lightning withstand level and reduce lightning trip rate. Verifies the relationship between grounding resistance, lightning line and lightning withstand level by simulation.Secondly, when lightning strikes a tower, influence of arrester on lightning withstand level, tower diversion coefficient and flashover phase of insulator is deduced by numerical model analysis, and verifies the conclusion take 35 kV Shang type tower as an example by simulation. The best installation principle of line lightning arrester on 35 kV single tower is obtained by comparative analysis of the reasons for the difference between the calculation and simulation. Study on influence of installing lighting arrester where easy to suffer the lightning strike and near on the lightning protection for 35 kV overhead line to explore the optimal principle of multi tower continuous lightning arrester installation.At last, when lightning strikes a wire, influence of arrester on lightning withstand level is deduced by numerical model analysis. Calculated result shows that, the lightning shielding in the branch equipped with lightning arrester, lightning protection level could increase significantly, and whether the other two branches have been installed lightning arrester or not is almost the same; the lightning withstand level has nothing to do with shielding-failure position. Verifies the accuracy of the conclusion take 35 kV transmission line as an example by simulation, and explores the best installation location of arrester.Engineering practice shows its good effect on applying the research results of this paper to the practical lightning protection engineering.