Research on the Lightning Protection of UHV Long-distance GIL System

when the transmission channel is limited or Overhead line corridor is tensional, ultra-high voltage (UHV) gas insulated transmission line (GIL) technology has a wide application prospect. GIL has been widely applied at the voltage level from 73kV to 800kV in the world. Sutong GIL (from Suzhou to Taizhou in China) pipe gallery project is an ultra-long distance GIL project with the highest voltage level, the largest transmission capacity and the highest technical level in the world. For Long-distance GIL at the voltage of 1000kV, there is no mature technology at home and abroad. When UHV GIL and overhead hybrid transmission lines are struck by the lightning, UHV GIL will withstand the corresponding lightning intruding overvoltage. In this paper, lightning protection researches of UHV long distance GIL system for the first time were carried out based on the project from Suzhou to Taizhou by ATP-EMTP. Firstly, the lightning overvoltage simulation model is established to carry out the lightning overvoltage research of UHV GIL system. Secondly the overvoltage characteristics of UHV GIL system subjected to lightning intrusion wave and the distribution of lightning overvoltage in the GIL are analyzed. Thirdly, the layout scheme of lightning arrester between GIL and overhead hybrid transmission line is given. Researched results have been used in the engineering design of the UHV Long-distance GIL system from Suzhou to Taizhou.