中文摘要：

采用特高压现有无穷大电势源等值法获取端电压二维控制域时,会得出投入容性无功补偿将降低特高压沿线电压这一＂错误＂结论,对此研究证明：变压器中压侧绕组等效阻抗为负是造成二维电压运行下限上移的主要原因。提出了一种新的等值电势源法,即将华中电网和华北电网分别等效成含内阻抗的电势源。采用该等值方法时,无功补偿装置的投切所引起的电压控制域的变化趋势与电压无功理论相符,同时还可以考虑线路输送功率变化时,由线路功率和两端母线电压共同形成的三维控制域。

英文摘要：

The two-dimensional control domain of the ultra-high voltage（UHV）,formed by the two terminal bus voltage,is commonly calculated by using existing UHV infinite equivalent potential source method,which will lead to decrease of voltage along the UHV line after switching the capacitive reactive power compensation devices.It＇s found that the minus equivalent reactance on the medium-voltage side winding of the transformer is the main reason.Hence,a novel equivalent potential source method is proposed for the control domain calculation,in which the Central China grid and North China grid systems are modeled as the equivalent potential sources with inner impedance respectively.Comparing with the bus voltage method,the proposed method can not only eliminate the reverse moving of the control domain but also develop a three-dimension voltage control domain formed by line power and two-terminal bus voltage by taking into account of the variation of the transmission power variation.This work is supported by Key Project of National Natural Science Foundation of China（No.51071185）.