Design of decentralized biased dual mode controller for load frequency control of an interconnected power system with AC/DC tie lines

An efficient load frequency controller is important to maintain power flow and frequency within acceptable limits. This paper proposes an application of Dual-mode controller which is simple in structure and easy to implement for load frequency control of an interconnected thermal power system with AC/ DC tie lines considering area control error based on the tie line power deviation and frequency deviation. Optimum proportional integral controllers using the Integral Square Error (ISE) criterion has been obtained for a step load disturbance. Results reveals that the controller based on Dual mode always guarantees zero steady state. Settling time for tie line power and frequency deviation is found to be faster than the conventional proportional integral controller.