Calculation and Analysis of the Coupling Effects of the Ultra High Voltage Double-circuit Transmission Lines

There exist serious coupling effects between the ultra high voltage(UHV) double-circuit transmission lines. In spite of elucidating detailedly both the static and the electromagnetic coupling mechanisms, the impacts of the line transposition mode on the induced voltages and currents are analyzed via established equivalent circuit model. As a case study which incorporates UHV double-circuit lines to be built in east China, the induced voltage and current along the maintenance line under different conditions have been calculated through ATP-EMTP. Specifically, the influence of both the compensation factor and the neutral reactor value on the induced voltages along the maintenance line is investigated while shunt reactors are installed, which indicates that extremely high induced resonant overvoltage may potentially happen in some critical cases. The research results present useful reference for future construction of the UHV double-circuit transmission lines.