Power System Frequency Dynamics and Application of Energy Storage Systems Towards Achieving 100% Renewable Grids

Electricity generation in conventional power systems is mostly obtained through the use of synchronous machines, which determine system frequency due to their electromechanical coupling. These machines relieve fluctuations in the generation-load balance through the absorption and release of kinetic energy, and large frequency excursions are prevented by the inertia of the rotating masses. Renewable technologies such as Wind Turbine Generators and Photovoltaic Panels require the use of power electronics to interface with the grid and do not provide inertia. Thus, system overall rotational inertia is decreased as the share of inverter-based renewable technologies increases. This thesis presents an analysis of the effects on system frequency dynamics, specifically on the inertial response and Rate of Change of Frequency (RoCoF), due to increased penetration of Renewable Energy Sources (RES). This thesis proposes a methodology for the application of Energy Storage Systems that will allow power grid to maintain robustness against frequency deviations. This is a significant challenge to resolve in order to transition into environmentally-friendly power networks, with the ultimate objective of achieving 100% renewable grids.