A Review On Quantitative Feedback Theory (Qft) To Maintain Power System Stability

There are different practical methods which are used to maintain the power system stability but these systems are characterized by high uncertainty which makes it difficult to maintain good stability. In case of conventional methods, if plant parameter changes we cannot assure about the system performance hence it is necessary to design robust control for uncertain plant. Among the various strategies proposed to tackle this problem, Quantitative Feedback Theory (QFT) has proved its superiority.[6] QFT falls into the classical control category, and is a frequency domain design method. It is an alternative to other design methods such as root locus and H∞. From theory, through simulation, on a single machine, infinite bus system, it will be shown that the application of QFT to robust PSS design does indeed work.Other methods allow the designer to produce a design for single operating point and one has no idea how the design performs at the other operating points. QFT is a design method that allows the designer to choose a set of realistic operating points and to produce a design that includes those points. [6]