分布式发电条件下的新型电流保护方案

根据分布式发电（DG）接入配电网后网络结构和故障电流的变化特点，提出了一种新型电流保护方案。该方案利用电流综合幅值的比较将故障范围缩小到一个故障搜索区域之间，然后利用该区域电流间的相位关系对故障线段进行定位。文中详细论证了故障搜索的电流幅值判据和故障判断的电流相位判据，并分别提出了其矩阵算法，该算法对DG投退造成的网络结构的随机变化具有自适应性，对智能电子设备（IED）故障具备一定的容错能力，满足DG接入对配电网保护提出的要求。利用IED进行分布式处理，降低了保护对通信系统的要求，同时，由于仅利用电流量进行故障搜索判定，工程上较容易实现。文中对该电流保护方案进行了算例仿真，证明了方案的正确性。

New Current Protection Scheme Considering Distributed Generation Impact

In the distribution network with distributed generation(DG),the single-source radiate network based protection scheme is no longer suitable and loses its original protection coordination.Based on multi-DG distribution network structure and fault current characteristics,this paper proposes a new adaptive fault location method which can be used for current protection design.This new current protection scheme includes two steps:first,the fault search direction is obtained through current magnitude comparison;this will narrow down the possible fault region within two three-branch buses.Secondly,phasor relationship between current positive sequence component and load current at the both ends of the feeder is used to locate the fault section along the feeder.This is realized in an adaptive fault searching region lock matrix algorithm,which avoids the matrix multiply operation.This is simple and practical.The validity of the proposed protection algorithms is verified by the simulation result.