Modelling and Simulation of a Stand-Alone Hybrid Power Generation System Incorporating Redox Flow Battery Storage System

Abstract Wind turbines often ply turbulent wind gusts and therefore spit out an irregular stream of power that is tough for the autonomous power systems to swallow. Moreover, the changes in consumer load and system configuration in such autonomous power systems represent relatively significant changes due to overall low system inertia. These characteristics coupled with the wind’s intermittence and presence of induction generators play havoc with stand-alone power systems like wind—diesel ones in terms of power quality. However, energy storage devices with quick response can effectively increase the utilization of wind energy and improve the power quality. Redox flow batteries (RFB) have many salient features which make them ideal for use in stand-alone power systems. In this paper, we study a hybrid multi-machine power system, comprising of wind energy conversion units, diesels and an RFB system. The interfacing of RFB to wind park bus is proposed to take place through a current-controlled voltage source inverter (CC-VSI), based on hysteresis control. An intelligent control policy based on fuzzy logic is adopted for active/reactive power modulation of the RFB in four quadrants of the power chart. The detailed dynamic equations of the various components of the hybrid power system are presented. Unified models are finally developed for assessment of the proposed scheme. The simulation studies based on this model demonstrate the ability of the proposed novel scheme in assisting the system voltage and frequency regulation under various perturbations.