Thyristor-based flexible ac transmission system for controlling the vanadium redox flow battery

The vanadium redox flow battery (VRB) is a large stationary energy storage system; which presents high-speed response and overload capacity characteristics. The VRB produces a dc voltage between two terminals; so a power conditioning system composed principally by a dc/ac flexible ac transmission system (FACTS), is required in order to connect the battery to the power system. In this regard, this study proposes a new FACTS compensator for controlling the VRB based on a 12-pulse thyristor converter with commutated capacitors on the ac side. This type of compensator offers a good transient response with low-power converter losses. Simulations of the FACTS compensator employing Matlab/Simulink software validate the proposal and show the good performance of the proposed device.