Dynamic behavior improvement in a microgrid with multiple DG units using a power sharing approach

This paper investigates dynamic behavior of a distribution subsystem (microgrid) with three distributed generation (DG) units to planned and accidental switching event. Three DG units are one gas-turbine synchronous generator and a variable-speed wind turbine with doubly fed induction generator (DFIG) and a converter based DG. A power control approach is proposed for DG units to provide both voltage and frequency regulation capability and hence an improvement on transients and dynamic behavior of a microgrid system. Two distinct operation modes, i.e. grid-connected and islanding mode are used in the proposed approach for proper transfer from normal to islanding operation. Case studies are simulated based on both planned and unplanned islanding scenarios to evaluate the performance of the control approach. The study results show that the proposed power sharing approach for DGs in the microgrid may contribute to mitigate microgrid system transients, improving dynamic performance, and reducing frequency changes following disturbances that subsequent to islanding.