Design of decentralized biased controllers for load-frequency control of interconnected power systems

This article proposes a design of biased controllers for the decentralized load-frequency control of interconnected power systems. Conventional load-frequency controllers are usually implemented in a proportional plus integral form using area control error (ACE) in order to obtain satisfactory results. In this article, the optimum proportional plus integral biased controllers are designed using integral squared error (ISE) criterion as well as maximum stability margin (MSM) criterion to obtain better transient and steady-state responses. These controllers are designed and implemented in a two-area interconnected thermal power system. The system was simulated and the frequency and tie-line power deviations resulting for a step load disturbance are presented. The results reveal that the biased controllers provide better transient as well as steady-state response and increased stability margin when compared with the responses obtained using conventional controllers. It is also found that the biased controllers are less sensitive to the changes in system parameters.