Power flow calculation method for isolated microgrid considering the influence of harmonic power

In isolated microgrids, with the increasing application of the nonlinear load, the interaction between the harmonic and fundamental voltages/currents becomes more conspicuous, so that the harmonic power should be considered in the process of power flow calculation (PFC). For this reason, this study proposes a method for PFC considering the harmonic power based on the models for the microgrid system and harmonic sources (e.g. rectifier device), the currents' physical components power theory, as well as the operational characteristics of the isolated microgrid. According to the proposed method, the fundamental power flow is first obtained by analysing the operation modes of the distributed generation units and non-linear loads. Then, the harmonic voltages and currents are calculated based on the fundamental power flow, and the load-power correction for the PFC, which is taken as the convergence condition of the iterative computation, is obtained by the harmonic power calculation. The test results applied in a 12-bus system verify the availability of the proposed method.