Load flow analysis for islanded microgrid

Abstract

Due to the increasing demand for green energy these last years, renewable energy sources have been integrated more efficiently with the utility grid .The combination of energy sources ,storage devices and the power electronics interface with the aim of satisfying the load is called a microgrid. A microgrid can deliver energy autonomously in the islanded mode, which make the object of electrifying the remote areas purely using renewable energy doable. The conventional load flow techniques cannot be implemented on the islanded microgrid because the voltage of slack bus and the frequency are assumed to be constant. This assumption fails to consider the real characteristics of the islanded microgrid where all the distributed generators share the load demand and the losses as well as maintaining the frequency. In this project, the conventional load flow technique using Newton Raphson is modified,combined with the droop control concept to predict efficiently the behaviour of an islanded microgrid .This prediction allows to compute the active power, reactive power and the voltage magnitude at each bus in addition to the frequency of the system. The algorithm is applied to 7-bus, 6-bus and 38-bus systems and the code is run on MATLAB software. The results obtained are compared with time domain simulations carried out by PSIM to assess the effectiveness and the robustness of the investigated algorithm .