Inertia Assessment of Interconnected Power Systems Based on Frequency and Tie-line Power Flow Measurements

Abstract:
The inertia provided by the rotating masses of conventional generators is essential for the frequency stability of electrical power systems, temporarily compensating for active power imbalances. Since power generation based on power electronics does not inherently contribute to the inertia of the system, the current trend of phasing out conventional generation while increasing inverter-based renewable generation leads to demand for monitoring inertia in the power system. This paper proposes a procedure for estimating the inertia area by area in an interconnected grid. The procedure is based on evaluating the active power flows via the tie-lines interconnecting the grid areas as well as the frequency deviation resulting from the simulation of a load step. For this purpose, an approach is derived to mathematically correct the calculation error due to the impact of the occurring rotor oscillations on the frequency.