Inertia characteristics and the real-time sensing technology of new-type power systems

Abstract

Integration of new energy sources will continuously encroach upon the startup capacity of conventional units， reducing system’s rotational inertia and frequency regulation capabilities. This leads to accelerated frequency changes and increased fluctuation amplitudes. Therefore， it is imperative for new energy units to provide active inertia support. However， the dynamic characteristics of new energy units differ significantly from synchronous generators， making traditional swing equations inadequate to fully reflect the dynamic process of frequency response in new-type power systems after disturbances. Therefore， an inertia model for new-type power systems is established to accurately characterize the inertia response process of synchronous generators， grid-following inverters， and grid-forming inverters. A real-time inertia measurement method is proposed， which employs an improved polynomial curve fitting method （PCFM） and system identification method to accurately identify the system’s rotational inertia and regional inertia. Finally， through simulation， a quantitative assessment of the equivalent inertia of new-type power systems is conducted， and the effectiveness of the proposed measurement method and mathematical model is validated.

Keywords

• inertia of power system
• frequency response
• virtual inertia
• inertia estimation
• step response