Evaluation of control maintaining electric power quality by use of rechargeable battery system

The rechargeable batteries like redox flow which are not aged by frequent charging/discharging, have a quick response equivalent to SMES and outstanding capability of overload. The response time and the maximum overload rate of redox flow battery are verified as 350 /spl mu/s and 4.6 times. These systems are advantageous for power control under wide frequency band which covers from spinning reserve to economic load dispatching, and also used for leveling load and maintaining power quality. The instantaneous controls using these systems are effective for dynamic stability, flicker, voltage dip and charging/discharging regenerative power of electric railways. The authors clarify the chemical reactive characteristics of the redox flow battery physically and the effect of secondary control utilizing characteristics of quick response and overload capability of the redox flow battery by dynamic simulation. The battery efficiency increases when the cycle period of charging/discharging becomes shorter. The comprehension about these performances can be used to determine the optimum rechargeable battery system configuration for each use of end users.