一种解决三相故障失去方向性的实用判据

A method for three-phase fault lost directivity

电力系统线路经小电阻短路时,可能导致距离继电器区外超越以及在背后母线三相经小电阻短路时误动。以阻抗圆继电器为例在阻抗平面上分析了由于过渡电阻引起区外超越和反方向误动的原因,并在电压平面上用向量图对比分析了用不同极化电压形成动作圆时过渡电阻对它产生的影响,在其基础上提出了一种解决这种区外误动实用方法,即用相位突变量距离继电器防止记忆电压消失后阻抗继电器失去方向性的问题,从向量图分析可以看出这种方法是可行的,并且装置的动模试验结果也验证了其可行性。

When the electric power system of line has faults with transition resistor, the distance protection maybe lose direction or trip when the faults are outside of protection range. The paper analyzes the reason of losing directivity and overreach faults using resistance vectogram. And it also analyzes the effects of transition resistor on distance relay when using some different polarizing voltage on the voltage vectogram. It gives a method to resolve this problem, i.e. using power variation distance relay to avoid losing direction when memorization voltage lost. The vectogram tests and verifies this principle and dynamic analogies examination proves its feasibility.