Ali M. Yousef ,. N. M. Ashtawa ,. M. R. Abuzied
Electrical Engineering Department, Faculty of Engineering / Gharian
Al-Jabal Al-Gharby University
A proposed PSS suitable for power system under loading condition based on linear-quadratic
regulator (LQR) control has been established. The power system under study consists of a
synchronous machine connected to an infinite bus through transmission line. The output of
such stabilizer is fed directly to the automatic voltage regulator (AVR) of the synchronous
machine. The input to such stabilizer are four state variables, two are accessible which are the
deviation of the speed (Δω) and rotor angle(Δδ ). The other two inaccessible states that are
the deviation of the Voltage proportional to q-axis flux linkage. ( '
q ΔE ) and the Generator
field voltage ( fd ΔE ). An observer has been designed to access the two inaccessible states.
Digital simulation Matlab program and Simulink have verified the effectiveness of the
proposed PSS. The digital simulation responses have been drawing at different operating
conditions. The results proved the robustness and powerful of the proposed LQR stabilizer in
terms of fast damping response and less settling time of power system state time responses.
The digital simulation results show that the proposed robust LQR- PSS can achieve good
performance over a wide range of operating conditions. Moreover, a comparison between
power system time responses at variety of operating points using pole-placement approach
and the proposed robust LQR-PSS is carried out.