锦屏—苏南±800kV特高压直流输电工程换流站过电压及绝缘配合(英文)

Regarding to the problems of equipments manufacturing and layout in Jinping-Sunan ±800 kV UHVDC transmission system,overvoltage protection and insulation coordination in converter stations were studied.Configuration of arresters was studied at first,and scheme of MH arresters and V arresters connected in series was used to protect the high voltage Yy transformer’s valve side of dual 12-pulse converters.Overvoltage caused by DC faults and the withstand level of equipment in converter stations were studied using electromagnetic transient simulation.Based on operation parameters and characteristics of AC and DC system,equivalent models of both systems were set,together with most of the equipment in converter stations which would influence simulation results.The AC arresters’ transient response to AC faults was also simulated.For the most severe case,the peak voltage on AC bus arresters is up to 752 kV,along with stresses about 12.0 MJ in energy and 12.4 kA in current.Simulation results of transient overvoltage in converter stations were used to verify insulation coordination by comparing with the design value.The maximum insulation level would be less than 1 600 kV,which is no more than that in former UHVDC projects.