Modern Power System Frequency Response Security Region Considering Safety Constraints

The large-scale integration of renewable energy sources (RESs) has posed significant challenges to power system frequency stability, creating new requirements for power system safe operation. Therefore, evaluating the frequency security boundaries under potential faults is necessary to determine the system's minimum frequency response resources (FRRs) requirement. This paper proposes a method to evaluate the frequency response security region of system inertia response (IR) and primary frequency response (PFR) resources based on the system frequency response (SFR) model. The proposed assessment method comprehensively incorporates essential safety metrics, including the rate of change of frequency (RoCoF), frequency nadir (FN), and quasi-static frequency deviation (QSSFD), while also considering the feasible capacities of IR and PFR. The effectiveness of the proposed method is demonstrated through case studies. Results show that the security region can accurately indicate the frequency resources adequacy, thus has practical applications in guiding the frequency regulation of the system.