分布式发电系统广域保护和故障定位技术研究

Distributed Generation System Wide-Area Protection and Fault Location Technology Research

分布式电源DG接入配电网以后,传统的三段式保护已很难满足配电网保护的要求。文章将基于多点信息的广域保护引入配电网保护中,提出一种基于通讯技术的故障定位新方案。结合广域保护集中式和分布式的特点,构建一种分层集中式保护通信结构;基于分层集中式结构进行馈线节点区域划分,区域划分综合考虑了保护投资、后备保护范围、DG控制、通信带宽和延时、区域均衡性等因素;故障一次定位,变电站中央处理单元利用馈线电流幅值和分段开关处的故障电流方向信息完成馈线选择和区域定位;故障二次定位,区域决策中心利用本区域内故障电流方向信息完成故障分支和故障点的定位;一次和二次定位方向判别算法不需要电压信息、减小了保护投资,没有负荷电流的参与、不受潮流方向和负荷轻载的影响。最后对某市实际10kV配电网进行案例分析,验证了该方案的正确性。

When(DG)connects with the distribution network,the traditional three-step protection can't meet the four basic requirement of relay protection.A new fault location scheme based on communication technology is proposed,which is based on the wide area protection of multi point information.In combination with the characteristics of wide area protection,centralized and distributed architecture is constructed;Based on the hierarchical centralized structure,the feeder node area is divided into a comprehensive consideration of the protection of investment,backup protection range,DG control,communication bandwidth and delay,regional balance and other factors;Fault location,the central processing unit of the substation is used to complete the feeder selection and location by using the fault current direction information of the feeder current and the fault current in the subsection switch;Fault location and fault current direction information is used to locate the fault branch and fault location to realize two fault location and regional decision center;First and the two positioning direction discrimination algorithm does not need voltage information,reduce the protection of investment,no load current participation,not affected by the direction of load and load light load.Finally,the actual analysis of city distribution network 10 kV case,verify the correctness of the program.