Evaluation of Inertial Response and Frequency Regulation in the Long-term Based on the Development Strategy of the Latvian Power System

The balance of electricity consumption and frequency regulation is the main technical problem in power systems with a high share of renewable energy sources leading to reducing the network inertia. As a result, the same level of imbalance of electricity supply and demand will have a greater impact on the system frequency with low inertia rather than with high. In turn, the problem of the lack or absence of stored energy could become especially acute in the event of an emergency failure of large power plants, not allowing them to fill the lack of power quickly and temporarily. This work aims to study the problem of maintaining the balance of power and frequency within normal operating limits based on the example of a simplified model of the Latvian power system developed in the Siemens PSS/E environment. As a solution, the combined use of synchronous capacitors and energy storage devices (the latter as sources of synthetic inertia) is proposed in case of sudden power changes in generation or load. The frequency response of the power system model has been investigated for both current and future development scenarios considering a significant increase in the share of generation from wind farms as well as the expected energy synchronization of the Baltic States with the energy systems of continental Europe in 2025.