计及谐波功率修正的独立微电网三相潮流计算

以整流装置带负载为代表的非线性负荷是引起微电网谐波的主要因素之一,而微电网中的非线性负荷比例越来越高,在潮流计算过程中必须考虑谐波潮流与基波潮流的相互影响。提出一种计及谐波功率修正的独立微电网潮流计算方法,该方法立足于独立微电网的运行控制特点和三相非正弦条件下的电流物理分量功率理论,将微电网系统模型及整流装置谐波源耦合矩阵建模作为分析基础;通过对分布式电源节点以及整流装置接口的处理,先求解交流基波的三相潮流,再计算各节点三相谐波电压和注入谐波电流,并以谐波功率对基波功率的修正偏差作为潮流计算的收敛条件。算例分析表明,采用上述独立微电网潮流计算及功率修正方法得出的潮流结果与时域仿真结果之间具有较好的对应关系,验证了所提方法的有效性。

Three-phase Power Flow Calculation for Isolated Microgrid Considering Harmonic Power Correction

The nonlinear load, such as rectifier device, is one of the main factors causing the issue of harmonic in the microgrid. With the increasing proportion of nonlinear load, however, the interaction between the fundamental power flow and the harmonic power flow should be considered in the process of power flow calculation. Based on this, a method for power flow calculation considering harmonic power correction is proposed based on the operational characteristic of isolated microgrid and the currents'' physical components theory under the condition of three phase non-sinusoidal. The microgrid system model and the harmonically coupled matrix modeling of the rectifier device are discussed as the analytical basis. At first, the fundamental power flow is calculated by the processing of the distributed generator and the rectifier interface. Furthermore, the three-phase harmonic voltages and currents are calcalated based on the fundamental power flow, and the corrected deviation for fundamental power flow, which is taken as the convergence condition of iteration for power flow calculation, is obtained by the harmonic power calculation. The test results show the correspondence between the proposed method and the time-domain simulation and verify the validity of the proposed method.