高压电网自适应接地距离保护研究

Study of the Adaptive Ground Distance Protection for High Voltage Network

为提高接地距离保护对高压电网高阻接地故障反应的灵敏性,提出了一种对过渡电阻Rg具有高度自适应动作边界的新型动作判据。根据接地阻抗继电器自适应动作判据的构成原则,在分析了负序电压极化的自适应阻抗继电器动作特性的基础上,分析了负序电压移相极化阻抗继电器的移相控制方法、移相极化的工作性能。分析表明,将负序电压根据近保护安装点侧系统的负序阻抗角的大小适当移相后作为极化电压,接地阻抗继电器对Rg不但有更好的自适应性,也保持了其方向动作的明确性。MATLAB仿真结果表明,新的动作判据确实提高了继电器对保护范围末端高阻接地故障动作的灵敏性和自适应性。

To improve reaction sensitivity of ground distance relay to high voltage high resistance ground fault, a new type of action criterion of highly adaptive protection boundary for transient resistances is put forward. The phase-shift control method of negative sequence voltage phase-shift impedance relay and working performance of phase- shift polarization are analyzed on the basis of forming principle of ground impedance relay adaptive action criterion and adaptive impedance relay characteristic of negative-sequence voltage polarization. The analysis shows that when the negative sequence voltage is properly phase-shifted to be the polarized voltage based on the negative sequence impedance angle size in near protection installation side system, the ground impedance relay has better adaptive characteristics to transient resistance and maintains its virtue of explicit protection direction. Matlab simulation results show that the new action criteria indeed improve the relay sensitivity and adaptability to high resistance ground fault at protection range tail end.