分布式发电对配电网线路保护影响的分析

Analysis of Impact of DGs on Line Protection of Distribution Networks

为了分析分布式电源(distribute dgeneration,DG)接入线路对重合闸和配电网线路保护的影响,以DG通过10kV线路并入配电网为例,考虑到DG接入容量较小、在配电网中接入位置不确定以及一次重合闸与DG的配合等问题,结合DG并网时电网拓扑,利用短路电流计算公式计算了电流的流向和大小,分析了DG在线路不同位置接入对配电网线路保护和重合闸的影响,指出在线路或系统出现任何形式的故障均快速无选择地切除DG的前提下,DG不会对原线路保护产生负面影响,无需更改原有线路保护的整定值。

To analyze the impact of connecting distributed generation （DG） with power distribution network on reclosure and line protection, taking the connection of DG with distribution network via 10kV line as background of the research and considering such factors as uncertain interconnection position of DG in distribution network, low connected capacity of DG and the coordination of one shot reclosure with DG~ the flow direction of value of the current are calculated by computing formula of short-circuit current based on the topology of power grid at the very moment of connecting DG in, and the impacts of connecting DG with distribution network in different positions on line protection and reclosure are analyzed. It is pointed out that when any kind of fault occurs in transmission line or power grid, so long as the DG could be switched off fast and unselectively, the DG would not have affect on intrinsic line protection, thus it is not necessary to change the setting of intrinsic line protection.