Abstract:
Low frequency oscillation is one of the major concerns for reliable operation of
power system, which occurs due to the failure of the rotor to supply sufficient damping torque to
compensate the imbalance between mechanical input and electrical output of a conventional
power system. In this research work, a third generation FACTS device named Generalized
Unified Power Flow Controller (GUPFC) based damping controller has been adopted in order to
investigate its effect for mitigating low frequency oscillation. To perform a comprehensive study
as well as to find the effectiveness of the designed damping controller, two conventional
controllers such as PI and Lead-Lag controller have been integrated for an Single Machine
Infinite Bus (SMIB) power system and test their performances on a separate manner. Later, since
improper modulation of gain and time constant parameters of these two above mentioned
controllers may lead to sub-optimal result, three different optimization algorithms such as Gray
Wolf Optimization (GWO), Differential Evolution (DE) optimization, and Particle Swarm
Optimization (PSO) have been adopted to tune these gains and time constants. Then, to study the
efficacy of these optimizers, time domain simulations as well as quantitative analysis have been
performed to find out the most suitable optimizer for each of the above controllers. Moreover,
two nonparametric statistical tests named as one sample Kolmogorov-Smirnov (KS) test and
paired sample t-test have been carried out to identify statistical distribution as well as uniqueness
of optimization algorithms. The results analysis reveals that the GWO tuned Lead-Lag based
damping controller for GUPFC shows superior performance in damping low frequency
oscillations for the study system.
