Occurrence of a fault in a power system causes transients. To stabilize the system, Power System Stabilizer (PSS) and Automatic Voltage Regulator (AVR) are used. This paper considers a typical Four-machine eleven-bus system forming two areas connected by two parallel lines as a case study for investigating the performance of UPFC in achieving stability. By using a UPFC the oscillation introduced by the faults, the rotor angle and speed deviations can be damped out quickly. In the study the UPFC is connected in one of the lines and the fault is assumed on the other line. The effectiveness of UPFC in suppressing power system oscillation is investigated by analyzing four oscillations in rotor angles and change in speeds that occurred in the three machine system considered in this work. A MATLAB simulation has been carried out to demonstrate the performance of the UPFC in achieving transient stability of the Four-machine eleven-bus two area system.
UPFC, faults, facts, MATLAB simulation
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