A novel algorithm for load flow analysis in island microgrids using an improved evolutionary algorithm

In an islanded microgrid mode, the use of conventional power flow method is not effective as the voltage of slack buses and the frequency of the microgrid is assumed to be constant. Such assumption fails to consider the real characteristics of an island microgrid as all distributed generations (DGs) are involved in providing the demand of active and reactive power as well as in maintaining the frequency of the microgrid. In this paper, a novel algorithm for the power flow problem in an island microgrid is proposed. The problem is modeled without any slack bus by considering the steady state frequency as one of the power flow problem variables. To model different control modes of DGs, such as droop, PV and PQ, in an islanded microgrid, a new formula for power flow equations is developed. A hybrid optimization method is developed, by adopting imperialist competitive algorithm (ICA) and genetic algorithm (GA), to minimize the objective function including total active and reactive power mismatch in an island microgrid.