Minimum Inertia Requirement Evaluation Method of Power Systems Considering Frequency Stability Constraints and Spatial Distribution Characteristics

The frequency stability of power systems under large disturbances has been severely hampered by the low inertia issue caused by the high proportion of renewable energy systems, resulting in frequency-related indicators closer to the boundary of the safety domain. This paper proposes a minimum inertia requirement evaluation approach for renewable energy power systems considering frequency stability constraints and spatial distribution characteristics. Firstly, a mathematical model of system frequency dynamic response is established, and the inertia center frequency is introduced to represent the frequency of the whole system (or regional system) to solve the problem of inconsistent frequency response process of different nodes. Then, an evaluation method is proposed to estimate the minimum inertia requirement of the system taking into account the frequency stability constraints, which avoids the issues of complex model construction and poor solving efficiency. This method combines the time-domain formulation of the inertia center frequency and the time-domain formulation of power systems frequency response with the primary frequency modulation dead zone. Finally, this paper verifies the validity of this method in a certain regional power grid and provides theoretical support for ensuring stable system operation and operating mode arrangement.