Mechanism of Inertia Loss and Evaluation of Inertia Level in Power Systems with Large Scale New Energy Access

[Introduction] In order to meet the national goals of "30·60" - peak carbon emissions by 2030 and achieving carbon neutrality by 2060, an influx of new energy sources such as wind and photovoltaic power is integrated into the system via converter interfaces and progressively supplants coal-fired synchronous generators, significantly impacting the power system's inertia characteristics and the associated frequency dynamic characteristics. [Method] Firstly, the study reviewed the inertia equation of motion for traditional power systems, and the power-frequency dynamic process during the inertia response phase following a disturbance in traditional generators, and then qualitatively discussed the mechanism of system inertia loss due to the extensive integration of new energy sources. [Result] The study considers evaluation indicators used at home and abroad for broadly recognized centralized inertia, and elucidates the reason for employing the system's total kinetic energy and inertia constant as the inertia evaluation indicators for the power grid. [Conclusion] Combined with the planning of new energy development and consumption of a provincial power grid, an engineering evaluation of the grid's inertia level is carried out, and the corresponding suggestions for inertia improvement are put forward.