Grid-connected wind farm power control using VRB-based energy storage system

To improve the power quality and stability of the grid-connected wind farm, and regulate the grid-connected power effectively, a new type of environmentally-friendly vanadium redox flow battery (VRB) based energy storage system (ESS) with many advantages are added at the exit of wind farm. A dynamic mathematic model of VRB based on the equivalent circuit is built. A bi-directional AC/DC converter is used to achieve the power conversion of VRB-based ESS and its corresponding control strategy is developed. The simulation model of the grid-connected wind farm with VRB-based ESS is established. The given wind speed in this paper is used for an example to validate the scheme, the simulated results show that the output active power of wind farm are effectively smoothed and a certain amount of reactive power support can be provided for the grid and the operating performance of grid-connected wind farm is well improved by the VRB-based ESS. The good charging-discharging performances of the VRB are also verified by simulated results.