Enhancement of stability of SMIB using ZN-PID and LQR-PSS as affected by excitation control

This paper presents the study of steady state stability of a synchronous machine connected to infinite bus (SMIB) through external reactance under small disturbance. The automatic voltage regulator (AVR) a part of the excitation control improves the steady-state stability of the power system but fails at high gain. Power system stabilizer (PSS) a supplementary controller added with AVR improves the synchronizing torque and reduces the oscillations of rotor angle and speed deviation. Proper response is achieved by PID controller. However, in this report, the desired response is found by proper tuning of PID controller using Ziegler-Nichols methods. Further, the PSS is designed and implemented using linear optimal controller called Linear Quadratic Regulator and helps in improving the system stability.