Simulation of a wind diesel power system with flywheel energy storage

Wind diesel power systems (WDPS) are isolated microgrids which combine diesel generators (DGs) with wind turbine generators (WTGs). The presented WDPS consists of a DG, a WTG, load and a low speed Flywheel Energy storage system (LS-FESS). First the dynamic models of the WDPS components are explained. Next, the LS-FESS active power control in the operation modes of Wind-Only (WO), where only the WTG supply active power, and Wind Diesel (WD), where both the DG and WTG supply active power, is described. The WDPS is simulated in WO mode facing load and wind power variations where the FESS is commanded to regulate the system frequency and in the transition from WO mode to WD mode to replace a supplying FESS with the DG, where the FESS makes possible a bumpless mode transition. The simulation results are given with graphs of the system frequency and voltage and active power in each component and the FESS-asynchronous machine variables: direct and quadrature currents, and speed.