Lightning Backflash Performance for ±500kV Double Circuit Transmission Lines

Adopting plusmn500 kV HVDC double circuit transmission lines to transmit power can both economize line corridor and add unit corridor aera transmission capacity, so plusmn500 kV HVDC double circuit transmission lines are more and more adopted. Because the length of double circuit transmission lines is high, it is more likely to be attacked by lightning stroke, so lightning performance for double circuit transmission lines is studied in this paper. Applying ATP can calculate backflashover withstand level when the datas like tower height, polarity configuration modes, soil resistivity and grounding resistance are changed. In the calculation, the insulators´ behavior is judged by comparing the insulators´ volt-time curves to the overvoltage, the system voltage and the induced voltage´s influence on lightning withstanding level is considered.