Frequency Characterization and Control for Future Low Inertia Systems

Fossil-fueled power plants in Danish power system will be phased out before 2050, where majority of the electric energy will be supplied by renewable generation. The conventional energy system comprises synchronous generators that provide inertia to support system frequency while the renewable plants mostly interface with grids by power electronic converters that have different frequency responses as synchronous generators.
To make sure a smooth transition from the traditional synchronous-machine-based system to a renewable-based system, this project will study the system inertia and frequency of a renewable-based system using future Danish power grid as a background. Firstly, a future Danish renewable-based system will be studied and modelled. Then, the system frequency characteristics will be considered according to different operational scenarios. Various operational conditions may include but not limited to, different situations of wind and solar output, demand response and power exchanges with neighboring countries. Finally, the requirements from ENTSO-E on renewable system synthetic inertia provisions will be incorporated into the renewable system modelling and the effects will be evaluated.
To improve the impact of renewable systems on system inertia, an application of synchronous condensers (SCs), a synchronous generator without prime mover will be investigated. The inertia contribution from SCs to the system may not be as significant as synchronous generators. However, it is still valuable for system operators to understand and perhaps use SCs for system frequency control.
Methods will be developed to simplify the modelling for system inertia quantification, as scenarios may change quickly in the future system. The frequency control scheme will be revisited and a new control design will be proposed.