Small Signal Stability Enhancement of Power System with GA Optimized PD type PSS and AVR Control

The small signal oscillatory instability is improved by adding sufficient damping torque for electromechanical modes of oscillations. The Heffron-Philips (HP) model which is equivalent linearization model of single machine infinite bus (SMIB) is considered for small signal stability. The power system stabilizer (PSS) with automatic voltage regulator (AVR) in synchronous generator produces sufficient damping torque and synchronizing torque so as to destabilize the small signal instability during small change in system variables. This paper presents the control design of PD based PSS which supplements the damping torque and reduces the transient oscillations by reducing setting time at constant damping ratio in system response. The controller parameters are tuned with Genetic Algorithm (GA) so as to minimize the speed deviation as objective function. The effectiveness of the controller is verified through time domain analysis at different loading conditions. The whole work is carried out under MATLAB environment platform.