A Model Predictive Control Design for Selective Modal Damping in Power Systems

Abstract

This paper presents a novel real-time predictive control technique to damp dominant inter-area oscillation modes in power systems. We first show that conventional Power System Stabilizers (PSS) in synchronous generators are best suited to damp only the intra-area oscillation modes and participate poorly in inter-area damping. We then design a centralized Model Predictive Controller (MPC) to provide supplementary control to these conventional PSSs based on a Selective Discrete Fourier Transform (SDFT) approach. The SDFT extracts the energies associated with the inter-area frequency components in the output spectrum of the system and uses this information to construct a weighting matrix Q. The MPC is then formulated as a quadratic minimization of the outputs using Q resulting in damping only the inter-area modes of interest. In reality however the most dominant DFT magnitudes will not be known ahead of time since they are decided by the location of the disturbance. Therefore we next augment the MPC design by predicting the dominant DFT magnitudes in the desired low frequency range using online measured data and tuning Q accordingly. We illustrate the effectiveness of the proposed approach using an IEEE 39-bus prototype power system model for the New England system.