Analysis of lightning shielding failure proof level of UHV transmission lines considering corona influences

An ATP-EMTP model for analyzing the lightning shielding failure proof levels of UHV transmission lines is presented in this paper. The rationality and availability of the proposed model was validated firstly. Then, the model was applied to the preliminary designed UHVAC transmission lines with four types of towers of the Chinese UHVAC demonstrating project to analyze the influence of corona on their lightning shielding failure proof levels. Conclusions are drawn through analyzing the simulation results. Impulse corona has an important influence on the lightning shielding failure proof level. Further more, the influence of corona increases when the voltage level is increased. The lightning shielding failure proof level of 1 000 kV transmission line increases about 40% when corona influence is under consideration. In addition, the influence of operating voltage on the lightning shielding failure proof levels was also analyzed based on the UHVAC transmission lines with ZMP2 type tower. When the corona influence is considered, the shielding failure proof level with considering the operating voltage is about 5.3 kA lower than that without considering the voltage. However, concerning with 500 kV transmission line, the difference is only 2.4 kA. It is shown that operating voltage has more visible influence on the UHV transmission line lightning shielding failure proof level. © 2009 Chin. Soc. for Elec. Eng.