Frequency Security Assessment of Power Systems Based on Dynamic Inertia Constants

With high-proportion renewable energy sources being continuously integrated into power systems, the system inertia provided by traditional synchronous units has shown a sustained downward trend. This trend has significantly exacerbated the risk of power system frequency instability. This paper proposes a frequency security assessment method based on dynamic inertia constants, aiming to address the insufficient spatiotemporal resolution of traditional static inertia assessment. By defining dynamic equivalent inertia, the real-time contribution of each unit to system inertia is quantified, and frequency security indices are constructed to achieve dynamic risk classification early warning in conjunction with the frequency deviation rate. Simulation results demonstrate that the dynamic inertia constants and frequency security indices can realize real-time tracking of the inertia output status of each generator and provide safety prompt warnings during faults.