Publication

Abstract : This paper presents an application of a Fractional Order Proportional Integral Derivative (FOPID) controller for load frequency control in a non-linear system. When the system is subjected to unit step load disturbance in any one of the area, the variations occur in frequency and tie-line power flow. To control the frequency and tie-line power flow between the areas, optimal secondary controller is required. In this work, Proportional Integral Derivative controller is used as secondary controller. For good approximation on the behaviour of the system, FOPID controller is used which analyses the integral and derivative order as fractions rather than integers. Simulated Annealing technique is employed for tuning the PID and FOPID controller gains on a large search space. As Flexible Alternating Current Transmission System device proves its flexibility of meeting the demand change at a faster rate before the secondary controller comes into action, Static Synchronous Series Compensator is incorporated along with the secondary controller for much improved control on the tie-line power flow. The response of FOPID controller with SSSC is found to be better and results are validated using performance indices.