Robust frequency control for power systems considering unknown delay and parameter uncertainties

Abstract

Delays in communication and variations in system parameters can have a significant effect on power system frequency. Thus, a delay-dependent robust PI frequency control scheme is proposed to address this issue. To begin with, a model that accounts for delays and parameter uncertainties is developed for the frequency control of a power system. Using Lyapunov stability theory and linear matrix inequality techniques, a new stability condition is derived, considering the effects of communication delays and uncertain parameters. This ensures that the control strategy remains efficient despite these challenges. The design of the PI-based frequency controller further incorporates an exponential decay rate to enhance robustness, with smaller exponential decay rate values selected for improved performance. The exponential decay rate is refined based on system performance under parameter uncertainties. Numerical results demonstrate that the proposed frequency control method is highly resilient to both communication delays and parameter fluctuations.