Application of Battery Energy Storage Systems to Enhance Power System Inertia

Conventional synchronous generators in traditional power systems are currently being replaced by various renewable sources, such as solar and wind. One of the consequences of this is the reduction of system inertia, which makes the system vulnerable to instability following a disturbance. Battery energy storage systems (BESS) are also increasingly being installed in modern power systems to mitigate the intermittency of renewable energy sources. This paper proposes a technique to improve system inertia by properly controlling the power absorbed/injected by the BESS using the derivative of frequency deviation as a control signal. The physical limitations of battery power and converter response time are properly incorporated into the BESS model, which is then integrated into the load frequency control model of a power system. The effectiveness of the proposed technique to improve inertia is then tested on a single-area and a two-area power system through the evaluation of rate of change of frequency (ROCOF) following a disturbance.