小电流接地系统功率方向元件动作行为分析

Behavior Analysis of Power Directional Element in Low Current Grounding System

在双电源配网系统中,将单电源系统的三段式电流保护与功率方向判别元件进行整合,构成方向性电流保护,可以快速、有选择性切除故障。分析了小电流接地系统配电网络方向性电流保护功率方向元件在两相相间短路故障时的动作行为,指出现有文献忽略过渡电阻的影响,存在疏漏,同时给出了准确的功率方向元件最大灵敏角整定范围。

In the dual power distribution network system,the three-stage current protection of the single power supply system is integrated with the power direction discrimination element to form a directional current protection,which can quickly and selectively remove the fault.The action behavior of the power directional element of directional current protection in the distribution network with low current grounding system when the diphasic phase fault occurred was analyzed.It is pointed out that the existing literature ignores the influence of the transition resistance due to careless omission.At the same time,the accurate setting range of the maximum sensitivity angle of the power direction element was given.