计及励磁控制响应的含小水电集群配电网复杂接地故障分析方法

小水电机组在配电网中的大规模接入增大了配电网拓扑的复杂程度，在恶劣气象条件下易发生复杂故障。同时，小水电励磁系统较快的响应速度使其对小水电故障输出电流的影响不能忽略。为此，通过对小水电机组故障特征的研究和对含小水电集群配电网复杂故障的分析，计及小水电励磁控制特性的影响，将小水电机组等效为由公共连接点(PCC)电压控制的压控电流源(VCCS)，并基于多口网络理论和理想变压器，构建出一种含小水电集群配电网复杂接地故障分析方法。经PSCAD/EMTDC全面仿真，结果证明该方法可精确求解复杂接地故障下小水电输出电流、系统各支路电流和各节点电压，可作为配电网复杂故障保护整定的理论依据，也可为含小水电集群配电网故障后孤岛划分和恢复重构提供理论支撑。

Complex grounding fault analysis method for distribution networks with micro-hydropower clusters considering excitation control response

The intensive access of micro-hydropower units increases the complexity of the topology of the distribution network, which is prone to complex faults under extreme weather conditions. At the same time, the fast response speed of micro-hydropower excitation system makes its influence on the output fault current of micro-hydropower cannot be ignored. Therefore, through the study on the fault characteristics of micro-hydropower units and the analysis of complex fault of distribution network with micro-hydropower clusters, considering the influence of the excitation control characteristics of micro-hydropower, micro-hydropower units are equivalent to VCCS(Voltage-Controlled Current Source) controlled by the voltage of PCC(Point of Common Coupling). Combined with the theory of multi-port network and the ideal transformer, a complex grounding fault analysis method for distribution networks with micro-hydropower clusters is constructed. Through the overall simulation by PSCAD/EMTDC, the results show that the proposed method can not only accurately compute the micro-hydropower output current, branch current and voltage of each node under complex grounding faults, and provide the theoretical basis for the protection setting of complex faults in distribution network, but also provide theoretical support for islanding division and restoration reconfiguration after faults of power system with micro-hydropower clusters.