A cooperative management strategy for battery energy storage system providing Enhanced Frequency Response

Abstract

The increased integration of renewable energy sources in the power grid reduces system stability, which translates to more frequency fluctuation. The UK National Grid Electricity Transmission (NGET) has introduced different frequency regulation strategies—Enhanced​ Frequency Response (EFR), and more recently Dynamic Containment (DC) to mitigate this issue. Compared to DC, the EFR includes an adjustable envelope for state of charge (SOC) management which results in better flexibility of the battery energy storage system (BESS). This paper conducts technical analysis and comparison on the two EFR services designed for BESS, and further proposes a cooperative control strategy combining the advantages of the two services based on EFR in order to achieve a better solution for both power grid and BESS. Case studies were carried out using real NGET frequency data to illustrate the schemes and verify the proposed strategy. EFR service 2 shows better frequency performance for frequency regulation while EFR service 1 behaves better in SOC management. The proposed strategy manages to incorporate the strength of both EFR services, which can be beneficial to the grid and BESS.

Keywords

• SOC management
• Enhanced frequency response
• Battery energy storage system