Power flow analysis in an Islanded microgrid without slack bus

Penetration of distributed generators (DGs) to the grid is transcending because of the importance given to green energy. Microgrids are gaining attention because of DGs and local control to reduce peak demand on the grid. Power flow analysis in microgrids must be considered while expanding the microgrids. Even though the conventional methods for power flow analysis apply to grid-connected mode, they cannot be used for an islanded mode of microgrid operation. Many modifications to the existing approach were proposed in the literature such as no slack bus, variable system frequency, and droop-controlled generators. A low-voltage microgrid of short distance which is for small communities is considered in the work. For such transmission lines, the resistance will be more than the line reactance. This paper focuses on modifying the conventional Gauss–Seidel method for the power flow analysis in low-voltage short transmission islanded microgrid. The power flow equations are modified considering there is no slack bus, and DG models are formulated for low-voltage, short transmission networks with droop control. The effectiveness of these considerations is illustrated by conducting simulation studies on a six-bus network and its effect on system frequency, real, and reactive power losses are also analyzed. The results obtained are compared with the existing results in the latest literature in which optimization techniques were used for droop coefficients calculation, and it is found that in the proposed approach, the real power losses are reduced by 2 kW without using any optimization algorithm for calculating the droop coefficients. Hence, the proposed approach is a good choice for power flow analysis in low-voltage microgrids for smaller communities.