Improving Dynamic Response of Hydro Power Plants Using Electrical Energy Storage in Low-inertia Power Grids

The share of renewable energies in the electricity generation side is increasing to replace fossil fuels and address environmental concerns. Consequently, the total rotational mass of conventional generations and the inertia of the power system will decrease. Here, first the potential of hydro power plant assisting the power system operator managing frequency deviations, in a low inertia power system is studied. Then, the capability of electrical energy storage (EES) to assist hydro power plant in primary frequency response services, is surveyed. The droop control method is considered for the operation of EES facility, with values of 1 and 5. Different case studies are defined, to study the impact of the hydro power plant and the EES facility on primary frequency response of the system. Based on the results, the hydro power plant will improve the settling time, and final recovered value of frequency of the system after a disturbance. However, it has a rather slow dynamic response facing deviations in the power system frequency. The EES facility has the best improvement in the Nadir point, while the settling point is better than when the system is without hydro power plant. Moreover, the final value of the frequency after a disturbance is also higher than the case without hydro power plant and EES facility. Finally, the droop control with value of 5 has better performance than droop with value of 1.