Stability Constrained Optimization in High IBR-Penetrated Power Systems-Part II: Constraint Validation and Applications

TL;DR

The paper tackles online stability constraints in power systems with high inverter-based resource penetration. It validates Part I's SOC-based stability constraints against dynamic EMT simulations on a modified IEEE-39 bus and integrates them into a stochastic, SOC-relaxed UC framework with a marginal-unit pricing mechanism for stability services. The work demonstrates how multiple stability criteria interact in scheduling, quantifies the economic impact of including stability constraints, and highlights the value of synthetic inertia and reactive power from IBRs. Practically, the approach enables economically efficient, stability-assured operation and informs the design of stability markets under increasing renewable and IBR integration.

Abstract

Multiple operational constraints of power system stability are derived analytically and reformulated into Second-Order Cone (SOC) form through a unification method in Part I of this paper. The accuracy and conservativeness of the proposed methods are illustrated in the second part. The validity of the developed constraints is tested against dynamic simulations carried out based on the modified IEEE 39-bus system. Furthermore, the developed power system stability constraints are applied to the optimal system scheduling model. The resulting stability-constrained system scheduling problem aims to achieve most economic system operation while ensuring different stability in power systems with high Inverter-Based Resources (IBR) penetration. Moreover, based on the stability-constrained optimization model, a novel marginal unit pricing scheme is proposed to quantify the stability services of different units appropriately according to their economic value in maintaining system stability, thus providing rational incentives to the stability service provider and insightful information for the stability market development.

Figures (11)

• Figure 1: Modified IEEE-39 bus system.
• Figure 2: PLL frequency with ($t\le2\,\mathrm{s}$) and without ($t>2\,\mathrm{s}$) equilibrium point.
• Figure 3: System dynamics after small disturbance at IBR terminal at $t=2\,\mathrm{s}$: (i) frequency deviation; (ii) active power deviation.
• Figure 4: System dynamics after step increment of IBR power references: (i) voltage trajectory; (ii) active power trajectory.
• Figure 5: System frequency evolution after a small step disturbance at $t=1\,\mathrm{s}$: (i) system SCC at different buses; (ii) bus voltages after three-phase short circuit fault at Bus 20.