Passivity Preserving Reduced Order Modelling For Efficient Emt Simulation of Large Power Networks

The high penetration of Inverter-Based Resources (IBRs) necessitates computationally intensive ElectroMagnetic Transient (EMT) simulations to analyze controller interactions. A practical challenge is that these studies are considerably time-consuming for large systems, and need to be done for different operating conditions and contingencies. Reducing the order of the model to form a reduced-order equivalent is a viable approach to speed up the simulation. In such models, it is important to ensure that (a) the reduced order model is accurate over a wide range of frequencies, and (b) the equivalent system is passive to reduce the chance of instability of the simulation. To address this issue, this paper presents a novel, passivity preserving model order reduction framework that achieves wideband accuracy. The proposed approach extends the classical moment-matching approach to match the system’s response at multiple frequency points to construct a passivity-preserving reduced-order model. The efficacy of the proposed technique is validated on the IEEE 39-bus system. Results demonstrate that the reduced models provide high fidelity over a wide frequency range, enabling a significant reduction in EMT simulation time without compromising the stability of the simulation.