Frequency regulation mechanism of energy storage system for the power grid

A stable frequency is essential to ensure the effective operation of the power systems and the customer appliances. The frequency of the power systems is maintained by keeping the balance between the demand and generation at all times. However, frequency changes are inevitable due to the power mismatch during peak hours particularly. With the increasing penetration of renewable energy (RE) especially solar photovoltaic (PV) in the grid, such phenomenon does not only decrease the grid inertia, the fluctuating power production contributes to the increased occurrence of significant power mismatches. Under the existing practice, any frequency changes are corrected by the governors of the power plants. Despite that, traditional power plants are limited in their ramp rate and duration. Therefore, energy storage system (ESS) is proposed to control the frequency of the power grid without having the grid service operator (GSO) to make significant structural changes to the network. The mechanism of the energy storage for regulating the frequency is developed in MATLAB/Simulink. The results show that ESS is able to carry out frequency regulation (FR) effectively while maintaining the stored energy continuously with the proposed offset heuristics. Case studies including high PV penetration and loss of largest generating unit (LGU) also highlight the potential of ESS to take over from spinning reserves.