Application of a NAS battery system for improving frequency control

As one of renewable energies, wind power generation is in great demand in the world. However, this type of power source is rather difficult to utilize because of its large fluctuation. To alleviate the fluctuation, a NAS battery system has been installed in a wind farm in Japan. And to manage wind power generations, some kind of battery output control is needed. Therefore in this paper, we propose a method to control the NAS battery system output according to wind power variations. To determine the control output, we propose to introduce a full order observer to estimate load disturbances. To verify the validity of the proposed method, we compare frequency deviations with a simplified method by carrying out LFC simulations.