中文摘要：

平行双回线结构的特殊性以及零序互感等因素造成距离保护继电器耐受过渡电阻的能力较弱，严重影响继电器的性能，传统的距离保护方法难以满足高压平行双回线的要求。该文针对双回输电线路的单回线路单相接地故障，提出双回输电线路的自适应距离保护方法，该方法借助正、负、零序电流的权重系数和传统距离保护的测量阻抗，计算出保护的附加测量阻抗，对传统距离保护的计算结果进行修正，并给出正、负分支系数相角的估算方法。仿真结果证明这种自适应距离保护方法能有效防止保护的超越和拒动。

英文摘要：

The structural particularity and zero-sequence mutual inductance of parallel double-circuit transmission line make the ability of distance protection to withstand transition resistance weaker, and it is difficult for traditional distance protection to meet the demand of high-voltage parallel double-circuit transmission line, so the performance of distance protection is seriously affected. In this paper, for the single-phase earth fault occurred in one circuit of the double-circuit transmission line an adaptive distance protection approach for parallel double-circuit transmission line is proposed. By means of weight coefficients of positive-, negative- and zero-sequence currents and the measured impedance in traditional distance protection, the additional measured impedance of the protection is calculated to modify the calculation results of traditional distance protection; and the method to estimate phase angles for positive- and negative-sequence branch coefficients is given. Simulation results show that the proposed adaptive distance protection can effectively prevent overreach and no-response of distance protection.