The new technological developments of UHV AC power transmission equipment

The UHV AC power transmission technology has developed quickly in China in the recent years, for which the main power equipment are most important. This paper summarizes recent technological developments of China's main UHV AC power equipment, including transformer, gas-insulated metal-enclosed switchgear (GIS), gas-insulated metal-enclosed transmission line (GIL), series compensation device and arrester, by introducing their use in UHV projects and related research. As for transformer, the insulation design for the UHV transformer, the control of leakage flux and temperature rise for large capacity UHV transformer, and the structure design of the disassembling UHV transformer are introduced. For GIS, the design for the UHV breaker with breaker capacity of 50 kA and 63kA, and the new generation are discussed respectively. For GIL, the key technology of the test line such as the long-pipe design, the built-in basin insulator, the design of support insulator and its application in the Sutong Comprehensive Tunnel Project are introduced. For series compensation, the composition and parameters of devices, and the spark gap technology are introduced. For arrester, the key technology of traditional UHV arrester and its development recently, and the development of controllable arrester are introduced. The future development of these equipment are also discussed in the paper.