Provision of Additional Inertia Support for a Power System Network Using Battery Energy Storage System

Battery energy storage system (BESS) will play important roles in the operation of future power systems integrated with high penetration of renewable energy sources. In this work, battery energy storage system (BESS) is equipped with a frequency controller to provide additional inertia support in a power system network made of wind power renewable energy and conventional sources. Several scenarios such as magnitude of power imbalance, transmission line length, variation in wind power penetration level, battery sizing, varying grid inertia were investigated to understand their impacts on the effectiveness of BESS in providing additional inertia support during power system contingencies. Time-domain simulation results of the studied network show that when the transmission line lengths are doubled, the rate of change of frequency (RoCoF) decreased by about 76% resulting in the minimum frequency rising from 49.39Hz to 49.85Hz during the power system disturbance. Besides, by increasing the size of BESS from 50MW to 130MW, the RoCoF was improved from -0.43876Hz/s to -0.30668Hz/s thereby raising the minimum frequency from 48.98Hz to 49.67Hz. Further results from the simulations show that when the magnitude of power imbalance was increased from 150 MW to 375MW, the BESS could not effectively provide additional support as the output power from the power converter remained fairly constant at about 60MW.