Improved inter-area stability using an LQG controller incorporating synchrophasor data

Abstract

There has been a recent increase in the deployment of phasor measurement units (PMUs) based on the IEEE C37.118 standard. Also referred to as synchrophasors, these have enabled the use of real-time frequency and frequency-rate measurements from generators and substations to be included in load-frequency control applications. This paper presents a method for improving the frequency damping characteristics of a three-area system that experiences 0.5 Hz oscillations. A linear quadratic Gaussian (LQG) controller is developed that includes a Kalman filter for the unmeasured states. An inter-area damping controller is developed using frequency measurements at a sample rate and resolution that would be achieved with IEEE C37.118 compliant synchrophasors in each of the three areas. Simulation results demonstrate the effectiveness of the proposed controller under realistic circumstances.