Table 5 Comparison of different performance indexes of IEEE first benchmark model with PI and with FOPI based STATCOM and UPFC controllers

1. LPB-GEN Torque (per unit)

With PI based controller the torque is reduced from 2.2 to 0.3 pu in case of STATCOM and from 0.46 to 0.09 pu with UPFC for a time interval of 1.05 s to 10 s. The torque is further more reduced with FOPI controller from 2.1 to 0.28 pu in case of STATCOM and from 0.42 to 0.08 in case of UPFC

2. LPB-GEN Stress (10⁷ N/m²)

The Mechanical stress between LPB and Generator is reduced from 2.2 × 10⁷ to 0.4 × 10⁷ N/m² and 0.45 to 0.06 × 10⁷ N/m² with PI based STATCOM and UPFC for a time interval of 1.05 to 10 s. Much more reduction of stress is obtained with the help of FOPI based controller from 2.1 × 10⁷ to 0.34 × 10⁷ N/m² and from 0.45 to 0.05 × 10⁷ N/m² in case of STATCOM and UPFC

3. Change in Electro-Magnetic Torque (per unit)

The Electromagnetic torque is reduced and reaches to a safe value from 0.9 to 0.05 and 0.27 to 0.01 pu with PI based STATCOM and UPFC controllers for a time interval of 1.05 to 10 s. With the use of FOPI in place of PI controller the change in Electromagnetic torque is further reduced from 0.86 to 0.04 pu and 0.25 to 0.01pu in case of STATCOM and UPFC

4. Change in Rotor Speed (per unit)

Without SSR controller the rotor speed is changes from 1.05 to 1.28 times. The change in Rotor speed is reduced from 1.008 to 1.002 and 1.0015 to 1.001 pu with PI based STATCOM and UPFC controllers for a time interval of 1.05 to 10 s. The use of FOPI in place of PI controller the change in Rotor speed is further reduced from1.0077 to1.0018 pu and 1.0012 to 1.001 with STATCOM and UPFC