Research and application of UHV power transmission in China

The power demand increases rapidly in China; however, the areas of huge power demands are of longdistance from most areas of abundant energy resource in the country. Therefore,China put in great effort to develop ultrahigh voltage (UHV) power transmissionsystems to optimise its energy allocation. This includes (i) systematicallydeveloping key technologies such as overvoltage suppression, external insulationdesign, and electromagnetic environment control, and (ii) developing keyequipment such as UHV alternative current (UHVAC) transformers, circuitbreakers, and series compensated equipment, and UHV direct current (UHVDC)converter transformers, smoothing reactors, converter valves, and DCtransmission control and protection systems. Eight AC UHV projects and 11 DC UHVprojects have been built in China, which play an important role in the optimalallocation of energy. Plus there are one more UHVAC and three more UHVDCtransmission projects in construction, while UHVAC gas‐insulated lines will beapplied in the UHVAC line crossover the Yangtze River and the ±1100 kV UHVDCpower transmission technology is in development. Here, the development andapplication of UHV power transmission technologies in China are described, somemain challenges the UHV projects encountered are discussed, and experiencesobtained from the operation of UHV systems are introduced. It is concluded thatChina obtained mature experience in developing, constructing, and operating UHVsystems and successfully realised long‐distance, large‐capacity powertransmission, and the UHV power transmission technology has become an importantmeasure for energy allocation in large areas.