A Control Architecture for Fast Frequency Regulation with Increasing Penetration of Inverter Based Resources

Abstract

This paper addresses frequency regulation under operational constraints in interconnected power systems with high penetration of inverter-based renewable generation. A two-layer control architecture is proposed that combines optimized droop and Virtual Synchronous Machine (VSM) primary control with a Model Predictive Control (MPC) secondary layer operating at realistic control-room update rates. Unlike recent proposed approaches, the proposed framework integrates MPC within existing grid control structures, enabling constraint-aware coordination. A reduced-order frequency response model is systematically derived from a high-fidelity grid model using Hankel singular values, and a reduced-order Kalman-Bucy observer enables state and disturbance estimation using only measurable outputs. Validation using representative data from the Kingdom of Saudi Arabia demonstrates effective frequency regulation under realistic operating conditions.

Figures (9)

• Figure 1: SFR model for the i-th operational region with $M_i$ SGs, $K_i$ converters, and tie-line power exchange.
• Figure 2: Regional frequency deviations of the KSA grid following a $0.02\ \text{p.u.}$. disturbance in the Central region, shown before (dashed) and after (solid) the projected 2030 IBR penetration. In the latter case, IBRs do not provide ancillary services.
• Figure 3: Schematic of the proposed optimal control scheme for frequency regulation in multi-area power grids. A/D and D/A denote Analog-to-Digital and Digital-to-Analog converters, respectively.
• Figure 4: Regional frequency deviation of the KSA grid following a 0.02 p.u. disturbance applied to each region, assuming no tie-line interconnections, shown with (solid) and without (dashed) IBR support under the projected 2030 RES penetration.
• Figure 5: Ratio $\rho$, as defined in (\ref{['eq:rho ratio']}), as a function of the number of states in the reduced-order model, $r$, for the (a) Eastern, (b) Central, (c) Western, and (d) Southern regions of the KSA power grid.