Feasible Ranges of Microgrid Parameters Based on Small-signal Stability Analysis

The transition from conventional generation to renewable energy sources (RES) motivated the energy sectors to focus on the microgrid (MG) concept. The stable operation of a microgrid is affected by multiple agents and parameters such as controllers, loads, lines, phase locked loop (PLL), and virtual impedances (VI). The virtual impedances (VI) was introduced to correct the impedance mismatches and subsequent performance characteristics in a MG. The effect of VI on MG stability is significant and should be analyzed thoroughly. This paper firstly draws the MG dynamic model including PLL, VI, current feedback coefficient (F) and induction machinery (IM). Then the non-linear dynamic equations are linearized around an operating point. Finally, the eigenvalues analysis is applied to evaluate the small-signal stability of islanded MG while the induction machinery (IM) and ideal resistive-inductive loads are installed at the MG, simultaneously. The permissible intervals for MG parameters are drawn from the MG stability point of view which is a useful procedure to control the MG effectively and inside a stable region of operation.