Stability analysis of weak rural electrification microgrids with droop-controlled rotational and electronic distributed generators

Droop-controlled distributed generation (DG) units are widely used in microgrids for rural electrification applications. In these microgrids, power quality is vulnerable to voltage and frequency instabilities due to limited generation capacities of DG units. More importantly, droop-controlled rotational and electronic DG units have different frequency dynamics, making a comprehensive stability analysis difficult. By introducing an equivalence between rotational and electronic generators, voltage stability and frequency synchronization conditions are derived as inequality constraints on network parameters, load levels and generator control commands. Satisfying these conditions ensures asymptotic voltage stability and frequency synchronization in a rural electrification microgrid. Moreover, these stability conditions help to economically expand isolated microgrids to a power distribution network that supplies reliable power services.