Page 166 - AJWEP-v22i2

Reddy and Kumar

of FACTS controllers with and without ACO. The table minimal generator oscillation, the maximum overshoot
compares the overshoot and settling time for ∆ω, rotor for the FACTS-only and ACO-based FACTS, ranged
angle deviation (∆δ), and voltage stability (δ) across from 0.09% to 7.25%, with the settling time for both
three cases: the base case (no FACTS controllers), ranging from 47.25 to 81.56%. The system’s ∆δ under
FACTS only, and FACTS with ACO. The results typical operating conditions is shown in Figure 8.
showed that the ACO-optimized FACTS controllers In the first scenario, the rotor angle variation was
significantly enhance the system’s stability by reducing oscillatory and took a long time to improve power
both overshoot and settling time. system stability, even if the system dampened the
For overshoot, the ACO-FACTS system achieved the LFO since the FACTS controllers were synchronized
lowest values, indicating better stability. For instance, with the ACO. When the power was changed, the
the overshoot in ∆ω reduced to 0.0155 pu with ACO- system became unstable, and the angle deviations were
FACTS compared to 0.0185 pu in the base case and exposed to further changes. The rotor angle under
0.0181 pu with FACTS only. Similarly, ∆δ overshoot normal loads is shown in Figure 8 for both the base case
decreased to -1.83 rad with ACO-FACTS, showcasing and the ACO with the FACTS scenario. The settling
improved stability compared to -2.014 rad in the base
case and -2.016 rad with FACTS only. δ also improved,
with the overshoot reducing to 1.97 in the ACO-
FACTS scenario, compared to 2.32 in the base case
and 2.11 with FACTS only. The settling time values
further demonstrate the effectiveness of ACO-FACTS
controllers. The settling time for ∆ω decreased to 3.12 s
with ACO-FACTS, a substantial improvement from 25
s in the base case and 9.2 s with FACTS only. Similarly,
∆δ and δ settled faster with ACO-FACTS, achieving 2.98
and 2.45 s, respectively, compared to the longer settling
times in the base and FACTS-only cases. These results
indicate that the ACO-FACTS combination enhances Figure 8. Rotor angle deviation under normal
the power system’s dynamic response by reducing loading conditions with FACTS, without FACTS,
overshoot and expediting stabilization, ultimately and with FACTS + ACO
improving overall reliability and performance. Abbreviations: ACO: Ant colony optimization;
The speed variations exhibited by the base case, FACTS: Flexible Alternating Current Transmission
FACTS only, and FACTS with ACO are shown in System.
Figure 7 under typical operating conditions. Due to

Figure 7. Rotor speed deviation with FACTS, Figure 9. Rotor speed deviation with FACTS,
without FACTS, and FACTS + ACO under normal without FACTS, and FACTS + ACO under heavy
loading conditions loading conditions
Abbreviations: ACO: Ant colony optimization; Abbreviations: ACO: Ant colony optimization;
FACTS: Flexible Alternating Current Transmission FACTS: Flexible Alternating Current Transmission
System. System.

Volume 22 Issue 2 (2025) 160 doi: 10.36922/ajwep.8393