基于序电流补偿的微电网三相潮流算法

Three-phase Power Flow Algorithm for Microgrid Based on Sequence Injection Current

由于微电网的网络参数不对称和负荷不平衡,使其三相不对称运行,从而传统的潮流算法不再适用于微电网。为此,提出一种基于稳态序电流的三相微电网潮流计算方法。针对微电网中的不对称线路和几种常见形式的负荷,引入基于电流补偿的线路和负荷的数学模型;并提出基于节点注入电流型的三相微电网潮流算法。将三相潮流问题转换成3个独立的电流方程,对正序应用Newton-Raphson方法进行潮流计算。为验证该算法的正确性和有效性,将计算结果与PSCAD/EMTDC的仿真结果进行对比分析。另外,为验证该方法可处理微电网潮流计算时遇到的线路高R/X比值及环网问题,对CIGRE MV微电网进行潮流计算,结果表明:基于电流注入模型的微电网潮流算法比传统潮流算法在计算速度和收敛性上更具优越性。

Due to the asymmetry of network parameters and load imbalance of microgrid, which make three-phase asymmetric operation exist in the microgrid, traditional power flow algorithm is no longer applicable to the microgrid. Therefore, a three-phase power flow calculation method based on steady-state sequence current is proposed. Mathematical model for lines and load based on current compensation is introduced for asymmetric transmission lines and common forms of load in microgrid. And a node current injection-based three-phase power flow calculation method is proposed. Those three-phase power flow problems are converted into three separate current equations, and Newton-Raphson method is used to calculate sequence power flow. In order to validate the accuracy and effectiveness of the proposed algorithm, the calculation results are compared with the simulation results using the PSCAD/EMTDC software tool. And in order to validate that the method can solve problems of high R/X ratio of the line and ring network which are encountered during the power flow calculation of the microgrid, power flow calculation of CIGRE MV microgrid is made. Calculation results show that the power flow algorithm for microgird based on the current-influx model is found to be superior to the traditional power flow calculation method in calculation speed and convergence.