A New Control Strategy to Integrate Flow Batteries into AC Micro-Grids with High Wind Power Penetration

The penetration of wind generation into AC micro-grids (MGs) has been increasing in recent years. Wind generation is uncontrollable, variable in nature, and uncertain. If the penetration level is high, the random variations of the wind power generation could cause problems for MGs to maintain the nominal system frequency. A typical solution is to employ energy storage systems (ESS) into the MG in order to compensate the wind power fluctuations. In this chapter, the use of a vanadium redox flow battery (VRFB) coupled with a power conditioning system (PCS) is suggested to enhance the frequency stability of a MG with high wind power penetration. A new control system is developed for the PCS/VRFB. The control system performs the load leveling of the wind generation and carries out the primary and secondary frequency control of the MG. Dynamic simulations of the proposed device are performed and demonstrate that the new control system improves the transient responses of the PCS/VRFB and the MG, during minor and/or severe disturbances