含多感应发电机的配电网短路计算对称分量法

Symmetrical Components Method for Short-circuit Current Calculation of Induction Generators in Distribution Network

短路电流计算是分布式电源接入配电网规划和保护的基础。文中根据感应发电机(IG)的故障响应特性,建立IG短路计算的序分量电流源模型;比较不同短路比下配电网发生短路故障时IG端电压和故障电流的响应,揭示出IG短路电流与配电网的耦合关系。应用叠加原理研究IG与配电网正负序网络的交互作用,推导了计及负序电压的故障点短路电流序分量计算公式,提出计算含多IG配电网短路电流的对称分量迭代算法。采用PSCAD/EMTDC仿真软件中IG的5阶动态模型仿真验证了该方法的正确性。

The induction generator（IG） short-circuit current calculation is an important foundation for planning and protection of distribution grid with distributed generation.According to the fault response characteristics of IG in distributed network,the current source model based on symmetrical components of IG is developed for short-circuit current calculation.Then the fault voltage and current responses of IGs under different short-circuit ratios（SCRs） are compared to investigate the coupled relationship between IGs and distribution network.By using the superposition principle of power system fault analysis,the interaction between IGs and the sequence networks is analyzed and the formula of short-circuit current sequence components at the fault bus considering its negative sequence voltage is derived.Finally,an iterative algorithm for calculating the sequence components of fault current for multiple IGs to integrate with the distribution network is proposed.The correctness of the proposed method is verified by the fifth electromagnetic transient model of IG in PSCAD/EMTDC simulation software.