A Novel Power Management Strategy for Frequency Regulation in Low Inertia Grid

Increased stability issues due to a decline in system inertia have led to the need for additional frequency response services in renewable integrated power grids. In the event of an increase or decrease in system frequency, quick acting energy storage can replicate the response of the conventional synchronous generator. Battery Energy Storage System (BESS) is a promising option for retaining grid stability and reliability by delivering frequency support services. This paper utilizes a time-derivative frequency signal and an SoC droop setting based control technique for BESS to produce an active power response for a deviation in system frequency. A novel power management technique incorporating the droop setting and a frequency deadband to ensure controlled charging and discharging of BESS in the context of safe operating limits is proposed. The proposed battery management strategy shows significant improvement in the SoC profile, battery reference power and utilisation of battery capacity. Simulation studies is performed on a modified IEEE-13 bus test system modelled as a low inertia grid. The effectiveness of the control strategy is verified by evaluating the frequency nadir,BESS response time, the change in frequency and the rate of change of frequency after a system disturbance.