距离保护元件在小电流接地系统中的特殊考虑

在小电流接地系统中,当采用两相星形接线方式时,距离保护元件需进行算法上的一些特殊处理。分析了系统发生三相短路和两相短路时的选相和测距的特殊考虑,并且针对系统发生异地不同名相两点接地故障中,距离保护元件的特殊处理方案进行了详细的分析,通过零序电流启动的接地距离保护与相间距离保护的动作行为以及两者之间的配合,保证了距离保护动作的选择性和可靠性。

Particular Considerations for Distance Protection Components in Small Current Grounding System

In case of adopting two-phase Y-connecting mode in small current grounding system, some particular processing in algorithm should be carried out for the distance protection components. The particular considerations for phase-choosing and distance-measuring in case of three-phase or two-phase short circuit is analysed. Directing against the particular processing scheme for distance-protection components during earth fault of two points at non-similar position and different phase is analysed in details. Through the action of earth distance protection and inter-phase distance protection started by zero-sequence current and coordination between them, the selective and reliable action of distance protection has been ensured.