孤岛运行的微电网三相不平衡潮流计算方法研究

Research on Unbalanced Three-phase Power Flow Calculation Method in Islanding Micro Grid

提出了适用于孤岛运行的微电网三相不平衡潮流计算方法:结合实际,对传统潮流计算方法予以改进,计算中考虑了配电系统各分布式电源的有功、无功控制能力,即电压、频率静态调节特性,考虑了变压器移相角对潮流的影响以及线路参数的相间耦合;算法采用相分量分析,能够应对线路参数三相不平衡、负荷三相不平衡等情况;用牛顿-拉夫逊法求解,易于处理环网结构配电网的潮流计算;不仅能进行三相不平衡潮流分析,还能同时计算出系统的频率.

This paper presented a new method for unbalanced three-phase power flow calculation in islanding micro grid. No balance node was set, while the auto power adjusting of each DGR, the static P-f and V-Q characteristics of each distributed generation resources （DGRs） were considered. The phase shifting in the power flow between the primary and the secondary windings of the transformer caused by the transformer winding connection and the coupling of the lines were also discussed. Using phase component, the three-phase power flow calculation method proposed in this paper can deal with several circumstances, such as asymmetrical line coefficients, and the unbalanced load of three phases. With Newton-Raphson method, it can solve the power flow calculation of the network in ringing topological structure. This work can make both the power flow and the frequency of the power system. This research provides a new reference for real unbalanced three-phase power flow calculation in islanding distributed power generation system.