From August 9 to August 10, SGCC organized an international symposium on the technology of UHV AC GDL in Beijing. Liu Zehong, vice president of the company, and relevant responsible comrades of the Science and Technology Equipment Department of the National Energy Administration attended and made speeches. The meeting introduced and discussed the project design plan and its significance, calling for a successful operation and long-term safe operation. Liu Zehong reviewed the important achievements made by State Grid Corporation of China and the electrician equipment manufacturing industry in uniting and coordinating with each other and tackling tough problems in project construction and equipment development in the past ten years and emphasized the importance of the project of the Sutong Special High Pressure GIL Pipe Gallery. Faced with the challenges, all units must adhere to the UHV as a top priority, adhere to the safety and reliability in the first place, adhere to the basic experience of open innovation, adhere to the economic and rational construction philosophy, co-ordinate the overall project technical solutions to solve Good key technical issues, to ensure the success of a successful operation, long-term safe operation of the goal. East China Electric Power Design Institute introduced the design of Su Tong pipe gallery project, China Electric Power Research Institute introduced the GIL technical specifications, Ping Gao, Xikong, the new Northeast, Shandong Electrician and AZZ, Siemens, ABB, GE and other domestic Foreign GIS and GIL major suppliers were introduced GIL product technical characteristics and the development of UHV initial ideas. Relevant responsible comrades of the National Equipment Administration of Science and Technology of the National Energy Administration affirmed the localization of equipment by SGCC over the years and put forward the hope of developing UHV GIL and promoting localization. Relevant units and invited experts present the key points and difficulties in the development of the GIL Pipe Gallery of Sutong. The key points and difficulties in the development of the GIL were analyzed and discussed. A series of specific proposals were made on the design scheme, technical specifications, equipment installation, tunnel layout, test and inspection, etc. Suggest. The Sutong GIL Pipeline Project is located at a distance of one thousand meters upstream of the Sutong Yangtze River Bridge. Through UHV GIL transmission technology, it crosses the Yangtze River through the river tunnel and is the key node of Huainan-Nanjing-Shanghai UHV AC Project. The project is the world's first UHV GIL power transmission pipeline project, the voltage level (1100 kV) and the application length (equivalent to a single-phase length of 35 km) are the world's highest, facing the high technical level, high reliability, Construction of the new challenges of great difficulty. July 29, 2016, the project was approved by the state, plans to start in August, completed and put into operation in 2019. After the completion of the project, it will form a UHV AC double-loop network covering East Anhui, Jiangsu, Zhejiang and Shanghai in east China area, which will be conducive to improving the power exchange capacity in the East China Power Grid area, accepting the incoming power outside the area and the system security and stability level, , To promote sustainable economic and social development of great significance. The meeting was presided over by Yu Xinqiang, the assistant to the general manager of the Company. 16 domestic experts, including the deputy chief engineer and academician Chen Weijiang from the Chinese Academy of Sciences, the relevant departments and units of the Company, major equipment manufacturers at home and abroad, representatives of engineering construction units and invited experts attended the meeting.