Challenges for a reduced inertia power system due to the large-scale integration of renewable energy

This paper reports on the status of technology development under a national project launched in 2019 to address the problem of decreased system inertia associated with the large-scale integration of renewable energy. The project comprises two parts: the development of a system inertia observation technology using a continuous monitoring system to observe inertia and development of an inverter equipped with a function to provide virtual inertia as a countermeasure device. Utilizing both these efforts, the project aims to facilitate the introduction of renewable energy in the future with minimum restrictions. It was confirmed that the trend of inertia observed with the developed method was generally the same as that of the total inertia of synchronous machines observed by an electric utility. The effectiveness of the countermeasure device in reducing the frequency swing during a disturbance was confirmed through evaluation tests.