The World's First Small Power Modulation Injection Approach for Inertia Estimation and Demonstration in the Island Grid

The introduction and expansion of renewable energy, has caused an emergence of problems in the operation and planning of power systems due to the decrease in inertial response possessed by synchronous generators. This topic is being discussed not only in Japan but also in the world due to its importance for maintaining power system stability. System inertia monitoring is one of the important applications in the maintenance and control of system frequency in the future power system which has more distributed generation and less synchronous machines. In this paper, a new method of estimating the system inertia constant by actively injecting small active power changes without affecting the system is described, and the demonstration results from a physical island grid are discussed.