FUZZY LOGIC POWER SYSTEM STABILIZER FOR IMPROVEMENT OF DYNAMIC PERFORMANCE OF MACHINE

Small signal stability is the ability of the power system to maintain synchronism under small perturbations. The small signal dynamic stability of electric power system has been the subject of major theoretical and practical interest and it continue to grow in importance as the control requirements of the power plants become more sophisticated and demanding torque. The range of 0.2 to 2.5 Hz. the damping characteristics of synchronous machine’s rotor oscillations is a function of system structures, operating condition and control structures. The power system stabilizers are widely used to damp out low frequency oscillations. Also, the optimum application of stabilizer is well defined and straightforward in cases where the instability is clearly identified with a machine or a group of machines. However, in more general case of widespread oscillation permeating a large interconnection, the identification of optimum sites for stabilizer application is complicated. Hence, in view of the potentially high costs of applying stabilizers to older machines, it is vital that the relative effectiveness of stabilizers at all system locations be studied and PSS be applied or provided at all new machines and retrofitted only to those older machines where they are essential for satisfactory system damping. In our example we will use the Participation factor and Sensitivity method for PSS location. According to Participation method which machine has the highest value of participation factor will be best suited for PSS location. According to Sensitivity method PSS will be located at that machine which has the highest value of Sensitivity facto