含PQ控制逆变型分布式电源的配电网故障分析方法

Fault Analysis on Distribution Network With Inverter Interfaced Distributed Generations Based on PQ Control Strategy

随着逆变型分布式电源(inverter interfaced distributed generation,IIDG)在配电网中的渗透率不断提高,且在新的故障穿越行为要求下,现有的故障分析方法已不再适用。为此,提出一种适应于最新并网规定的含PQ控制IIDG的配电网故障分析方法。该方法首先通过分析IIDG故障电流特性,提出计及控制特性的IIDG压控电流源等值模型;在此基础上,建立了故障下的含IIDG配电网节点电压方程,并针对不同IIDG间相互耦合以及公共连接点(point of common coupling,PCC)故障电压与IIDG故障电流之间存在非线性关系,提出相应的迭代修正求解方法。最后,通过算例仿真计算,验证了所提方法的可行性和有效性。

With continuously increasing penetration of the inverter interfaced distributed generations’ （IIDG’s） in the distribution network, the existing method of fault analysis is not applicable any more under the new code for the IIDG’s fault ride-through capability. Therefore, this paper proposed a method of fault analysis on distribution network containing PQ control strategy based IIDGs, which is suitable to the newest code. The method analyzed the fault current characteristic of the IIDG and then the voltage controlled current source equivalent model which considered its control scheme was built. Furthermore, the paper built the node voltage function of the network with IIDGs when fault occurred. And for the coupling effect among different IIDGs and non-linear relationship between the fault voltage of the point of common coupling and the fault current of the IIDG in the node function, an iterative correction method was proposed to solve the function. At last, test results verified the feasibility and validity of the proposed method.