平行双回线路故障分量电流平衡保护研究

传统的平行双回线路电流平衡保护存在灵敏度低、受过渡电阻影响大等缺点，难以满足高压平行双回线路的要求。该文给出了基于故障分量的电流平衡保护启动判据和选线判据。利用叠加原理和六序故障分量法分析了过渡电阻对选线判据的影响，给出了各种故障情况下两回线故障相故障分量电流幅值之比的表达式。给出了相继动作区故障时的电流平衡保护方案。理论分析和EMTP仿真表明，基于故障分量的选线判据几乎不受过渡电阻和负荷电流的影响，灵敏度得到了提高，可直接应用于目前微机保护装置。

Transverse Differential Protection Based on Fault Superimposed Components for Double-circuit Transmission Lines

Traditional transverse differential protection can't be applied to high-voltage power systems for its low insensitivity. A new current balance protection based on fault superimposed components is proposed, including the criterion of starting and fault line detection. This paper analyzes the influence on the protection behavior due to the transition resistance using superposition theorem and six-sequence fault components. It gives the analytical expression of the ratio of corresponding phase current, and the protection scheme for faults occur at successive action area. Theoretical analysis and EMTP simulation show that the sensitivity is free of transition resistance and load current for the criterion of faulty line detection. The protection scheme can be directly used in digital relays.