Frequency control of flywheel energy storage system based on a variable gain depending on the rotor speed and frequency deviation

회전자 속도와 주파수 편차에 따라 변하는 가변게인을 이용한 플라이휠 에너지 저장장치의 주파수 제어

Flywheel energy storage system (FESS) operates motor or generator by utilizing the stored kinetic energy in the rotating mass. Thus, the FESS can support the frequency control of the power system. However, the FESS is disabled when the rotor speed reaches to its minium value. Thus, the second frequency dip occurs in the power system. This paper proposes the frequency control scheme of FESS based on a variable gain depending on the rotor speed and frequency deviation. The proposed scheme prevents the second frequency dip because the variable gain decreases depending on the stored in the FESS. The performance of the proposed scheme is investigated for the IEEE 14-bus system.