Sanxiaproject is remarkable project in the world which have high technical and quality level for production, and UHV rating of the hydropower project most used 50 millionlevel.Nanjing electric (group) co., LTD. Since 1997, when the project first to the hydropower toughened glass insulator for San xia , send out for the hydropower of Sanxia project article 31 500 1.18 million kv line with toughened glass insulator products, accounting for about 60% of the total insulator used in the project, accounts for about 80% of the total glass insulator used in the project, the length of the line more than 5200 km, contribute to the San xia project electrical and mechanical equipment, and achieved good economic and social benefits.