Applications of a vanadium redox-flow battery to maintain power quality

The vanadium redox-flow battery (VRB) is a rechargeable battery. The VRB has a quick response time and an outstanding high-rate charge and discharge performance for short time periods. The capacity of the VRB can be easily specified by increasing or decreasing the quantity of electrolyte. By utilizing all these features, the VRB can form an effective system to maintain power quality, such as a voltage sag compensation system, a stabilizing system for output fluctuations of wind turbines. SEI delivered a VRB to a semiconductor plant as a voltage sag compensation system in April 2001. This system normally operates at the rated output of 1.5 MW as a load leveling system. Should a voltage sag occur, it can deliver 3 MW for 1.5 seconds. This VRB has already completely compensated 20 voltage sags. SEI delivered a VRB for the project of The New Energy and Industrial Technology Development Organization (NEDO) in March 2001, and it is under evaluation at a WT power plant of Hokkaido Electric Power Company. The VRB's rated output power is 170 kW, and it can be operated up to a maximum power of 275 kW. The VRB has already been found to demonstrate good performance.