Application of flower pollination algorithm for optimally tuning zeigler nichols parameters for PID controller to enhance transient stability through SVC

Abstract

With the evolution of electrical networks, the complexity and non linearity of modern power systems has enhanced exponentially. In order to reduce these potentially harmful oscillations, power system stabilizers (PSS) are introduced in generators of modern power systems. The PSS brings the system back to a stable and balanced state and re-establishes the pre-fault performance of the system after removal of disturbance and restoration of line. However utilization of PSS in certain cases of increased transmission line loading and other significant faults is not very effective and is rather time consuming. These days to acquire better control and quality of power, FACTS devices are being commonly used in large power systems. When SVC, a versatile FACTS device is used simultaneously with PSS, there is not only improvement in power transfer capability and controllability but also a distinct enhancement in power system stability. In order to increase the performance of the conventional PID controller of the PSS, it is tuned with a very simple and quick tuning method called Zeigler Nichols (ZN) which provides very fast elimination to disturbances in power system. However the conventional and ZN based PID controllers are confined only to linear control of power system. To further enhance the dynamic tuning process in order to obtain much faster and better transient as well as dynamic stability, a very adaptable and robust nature inspired technique of Flower Pollination Algorithm (FPA) is used to tune the ZN based PID controller. To realise the system transient stability for the conventional and proposed method, root locus and total harmonic distortion techniques have been adopted. The results ultimately reveal the efficacy and productiveness of FP based ZN-PID in successfully damping out inter area oscillations thus reducing the harmonics and improving overall stability in power systems as compared to other tuning methods.