含分布式电源的配电网故障分析的解耦相分量法

Decoupling phase domain method for fault analysis of distribution system with distributed generation

分布式发电系统的接入改变了配电系统的故障电流分布,传统的配电网故障分析方法已经不能满足未来分布式发电系统的需求。针对含分布式电源的配电网故障分析开展研究,提出了含分布式电源的配电网故障分析计算的解耦相分量法。将含有分布式电源的配电网分解成"梯形"网络和"辐射状"网络,选择短路点为边界节点,借助于相序参数变换技术,通过三相解耦等值电路计算故障点短路电流,并利用支路电流分流系数计算任意节点电压。所提算法无需形成配电网节点复数导纳或阻抗参数矩阵;可以精确地模拟故障;可方便地计及短路点接触电阻的影响;避免了复杂的序网连接。采用20节点算例对所提方法进行了测试,算例结果证明了该算法的可行性和有效性。

The distribution of fault current in distribution system is varied by the connection of distributed generation and the traditional fault analysis method is not suitable for distribution generation system（DGs）, for which the decoupling phase domain method is presented. The distribution network with DG is divided into ＂ladder network＂ and ＂radial network＂ and the short-circuit point is taken as the boundary node. The short -circuit current is calculated based on the phase- sequence parameter transformation and the decoupled three-phase equivalent circuit,and the voltage of arbitrary node is calculated with branch current diffiuence coefficients. The nodal complex admittance matrices of the network are thus avoided and the shortcircuit fault can be modeled accurately. The influence of fault point resistor can be easily considered and the complex connections between sequence networks are avoided. Test results for a 20-node system demonstrate the feasibility and effectiveness of the proposed method.