中文摘要：

高压输电线路距离继电器受故障点过渡电阻以及负荷电流的影响，可能出现误动的现象。分析推导了在相间故障情况下相间距离继电器的测量阻抗，研究了线路负荷电流对阻抗继电器动作特性的影响。指出重载线路末端发生相间故障的情况下，位于送电侧的超前相的相间距离继电器存在误动的可能，位于受电侧的滞后相的相间距离继电器存在误动的可能。最后提出了相间距离继电器的改进措施。大量仿真测试与现场故障实例验证了理论分析的正确性以及所提方法的有效性。

英文摘要：

The distance relay of transmission line may real-operate due to the influence of fault transit resistance and load current. The paper deduces measurement impedance expressions of phase-to-phase distance relay in the case of phase-to-phase faults. Based on the deduced expression of measurement impedance, the paper analyzes the influence of load current on distance relay, and then indicates that phase-to-phase distance relay of the leading phase at the sending end is possible to mal-operate when the transmission line is heavily loaded and the phase-to-phase fault occurs at the end of the transmission line, while the distance relay of the lagging phase at the receiving side may mal-operate. Eventually, the paper proposes the measure to improve the distance relay. Simulation tests and real fault record verify that the theoretical analysis and improved methods are correct and valid.