Analysis of Change in Frequency Characteristic under Operating Battery Energy Storage System(BESS) as Primary Control Reserve

Abstract

To maintain system frequency in power system, governor control and load frequency control systems are used. Therefore, the system operator has to operate system with standard reserve margin in real time. However, system frequency characteristic varies with generation mix despite of same amount of reserve in system. Under operating Battery Energy Storage System (BESS) as primary control reserve, the change in frequency characteristic can be larger. BESS has very short supply time. Therefore, after a large generator trip event the system reserve margin decreases. Fast start generator such as pumped storage power generator is connected to the system before BESS stops frequency response and restores the standard reserve margin. However, frequency characteristic of the system changes because generation mix which provide reserve changed. In this paper, under operating BESS as primary control reserve change in frequency characteristic when generation loss occurs is analyzed by frequency control simulation.