Power flow analysis for AC islanded microgrids

Abstract

The cluster of micro sources, storage devices integrated to power electronic interface to meet the load demand forms a small distributed network termed as a microgrid. The capability of the microgrid to act autonomously is an islanded microgrid, which fulfils the object of electrifying the remote areas by means of renewable sources. In an islanded Microgrid (MG), the use of conventional power flow analysis is not effective as the voltage of slack bus and the frequency of the MG are assumed to be constant. Such assumption fails to consider the real characteristics of the islanded MG as all distributed generators (DGs) are involved in providing the demand of active and reactive power as well as maintaining the frequency of the MG. In this project, simple algorithms are proposed for load flow solutions in islanded MGs to evaluate the frequency, Distributed generators active and reactive powers, voltage magnitudes and angles using Newton Raphson method with droop control-based concepts. The proposed methods are applied to 6-bus, 7-bus and 18-bus test systems and simulated based on the combination of two well-known software products, namely MATLAB and OpenDSS. The results are compared with time domain simulations conducted by PSIM which validate the effectiveness of the developed algorithms. In all cases, trivial differences are observed, validating the accuracy and the robustness of the proposed approaches.