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Stability Improvement of Power System by Using PI & PD Controller



Author(s)

Habibur Rahman, Rafiqul Islam Sheikh and Harun-Or-Rashid

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DOI:10.17265/1934-7332/2013.02.005

Department of EEE, Faculty of ECE, Rajshahi University of Engineering & Technology (RUET), Rajshahi 6204, Bangladesh

This paper presents the model of a SVC (Static VAR Compensator) which is controlled externally by a PI (Proportional Integral) & PD (Proportional Differential) controllers for the improvements of voltage stability and damping effect of an on line power system. Both controller parameters has been optimized by using Ziegler-Nichols close loop tuning method. Both single phase and three phase (L-L) faults have been considered in the research. In this paper, a power system network is considered which is simulated in the phasor simulation method & the network is simulated in four steps; without SVC, With SVC but no externally controlled, SVC with PI controller & SVC with PD controller. Simulation result shows that without SVC, the system parameters become unstable during faults. When SVC is imposed in the network, then system parameters become stable. Again, when SVC is controlled externally by PI & PD controllers, then system parameters becomes stable in faster way then without controller. It has been observed that the SVC ratings are only 50 MVA with controllers and 200 MVA without controllers. So, SVC with PI & PD controllers are more effective to enhance the voltage stability and increases power transmission capacity of a power system. The power system oscillations are also reduced with controllers in compared to that of without controllers. So with both controllers the system performance is greatly enhanced.

SVC (Static VAR Compensator), PI (Proportional Integral), PD (Proportional Differential) Controller, AVR, TCR (Thyristor Controlled Reactor), voltage regulation, MATLAB Simulink.