Development of an Optimal Frequency and Terminal Voltage Control of Two- Source Two-Area System Using Optimized Pid Controller

Abstract

The frequency and voltage challenges when subjected to load
disturbance in an interconnected power system has a negative
impact on power system stability. This research work is to develop
an optimal secondary controller for combined load frequency
control and automatic voltage regulation in two area
interconnected power system with thermal-hydro power plant in
each area. In this work, a proportional integral derivative (PID)
controller used for proper control of frequency, tie-line power and
voltage when subjected to the load disturbance instead of speed
governor alone (which is a primary controller). Then, one of the
soft computing techniques called sine-cosine algorithm (SCA)
proposed to be used in this study to optimized the PID controller
gains and ensure that the frequency, voltage and tie-line errors are
minimized to the optimal level. The optimized SCA-PID control
scheme was implemented on LFC-AVR model of two area
interconnected power system. The stability analysis carried out on
frequency, tie line power, voltage deviations and peak undershoot,
peak-overshoot and settling time were used as performance
metrics. The result reveals that the SCA optimized PID controller
has achieved reduced frequency undershoot and settling time of -
0.28Hz and -0.29Hz, signifying 60.86% and 61.7% and settling
time differences are -2.77 second and -2.37 second, signifying
56.76% and 54.48%, in area 1 & 2 respectively, over SA-tuned PID
controller, with little improvement in voltage reduced overshoot in
both area 1 & 2. Similarly, the tie-line power deviations settling
time found to be -0.51 second when the SCA- tuned PID controller
is applied. This also indicate 8.39% reduction in tie-line power
deviations settling time compared to SA-tuned PID control
technique. The results indicated that proposed Sine-Cosine
Algorithm outperformed the SA reported in the literature. The
proposed research work, show up an improvement in minimization
of the frequency, tie-line power and voltage deviations.