Page 167 - AJWEP-v22i2

Enhanced renewable integration for power system stability

Table 3. Performance of the power system under demanding operating conditions
Power system Overshoot Settling time (s)
states Base FACTS FACTS Base FACTS FACTS
case only with ACO case only with ACO
∆ω 0.0175 0.0171 0.0153 25 9.4 3.54
∆δ −2.06 −2.01 −1.76 25 10.7 2.86
δ 2.27 2.5 1.92 10.3 4.19 2.32
Notes: ∆ω: Speed deviation; ∆δ: Rotor angle deviation; δ: Voltage stability.
Abbreviations: ACO: Ant colony optimization; FACTS: Flexible Alternating Current Transmission System.

times for the FACTS and FACTS-ACO were 62.83 and
88.39%, respectively, and the largest overshoot was
0.15% and 13.75%. The ACO-based FACTS controllers
successfully stabilized the system under the existing
disturbance, in contrast to the base case.

5.2.2. Results from simulation under heavy operating
conditions
The ACO with FACTS controllers was selected for a
rapid load increment to generate a disturbance under Figure 10. Rotor angle deviation with FACTS,
demanding operating conditions. The power system’s without FACTS, and FACTS + ACO under heavy
performance under these conditions is displayed in loading conditions
Table 3. Table 3 showcases the system’s behavior under Abbreviations: ACO: Ant colony optimization;
demanding operating conditions, comparing the base FACTS: Flexible Alternating Current Transmission
case, FACTS only, and FACTS with ACO tuning. The System.
table evaluates the system’s stability based on overshoot
and settling time metrics. In terms of overshoot, the in Figure 9, which illustrates the enhanced damping
ACO-optimized FACTS controllers demonstrated performance achieved through ACO-optimized
improved performance. For angular ∆ω, the overshoot FACTS controllers. Overall, Table 3 highlights the
reduced from 0.0175 pu in the base case to 0.0171 pu effectiveness of ACO-optimized FACTS controllers
with FACTS, and further decreased to 0.0153 pu with in improving the power system’s stability under
ACO, indicating better speed stability. Similarly, ∆δ demanding conditions by reducing both overshoot and
overshoot decreased from -2.06 rad in the base case settling time, resulting in faster stabilization and better
to -2.01 rad with FACTS and further improved to -1.76 voltage regulation.
rad with ACO tuning, enhancing rotor stability. The δ The system’s angle deviation oscillated in the base
also benefited from ACO optimization, decreasing from case, but when ACO-based FACTS controllers were
2.27 in the base case to 1.92 with ACO, showcasing applied, the oscillations were reduced, and a steady state
better voltage regulation. was reached. As a result, adopting ACO-based FACTS
Regarding settling time, ACO-optimized damping controllers efficiently increased power system
FACTS controllers significantly enhanced system stability. The system achieved a steady state when a
responsiveness. The ∆ω settling time improved change in the rotor angle was converted into a negative
from 25 s in the base case to 9.4 s with FACTS, and change. The ∆δ for the FACTS controllers and the base
further reduced to 3.54 s with ACO, ensuring faster case with the ACO under heavy loading conditions are
stabilization. Similarly, the ∆δ settling time decreased shown in Figure 10.
from 25 s to 10.7 s with FACTS and further improved to The device exhibited interarea oscillation depending
2.86 s with ACO, indicating quicker system recovery. on angle stability. After reaching a maximum value,
The δ settling time also reduced significantly from 10.3 the oscillation started to decline as the system returned
s in the base case to 2.32 s with ACO, demonstrating to its normal value. The settling time for FACTS was
enhanced voltage stability. These improvements in 65.3%, and the settling time for ACO-based FACTS
rotor speed deviation under heavy loading are depicted was 87.2%.

Volume 22 Issue 2 (2025) 161 doi: 10.36922/ajwep.8393