Coordinated Control of PSS and SSSC Using Ant Colony Optimization

Small signal stability refers to the power system’s ability to maintain synchronism when subjected to minor disturbances. Instabilities that may occur in two main forms: a slow increase in rotor angle due to not enough synchronizing torque, and rotor oscillations with increasing size due to not enough damping torque. To solve these problems, generators are equipped with PSSs, which improve the damping of low-frequency oscillations, usually between 0.2 to 3.0 Hz, making the power system more stable. Simultaneously, the SSSC as damping controller, also can contributes to power flow control and voltage stability by dynamically regulating line impedance. However, a proper coordination between PSSs and SSSC is essential for extracting the effect of combined operation. In this paper both PSS and SSSC are effectively coordinated by optimising their parameters using ACO algorithm. Also, this paper compares the stability of the test system with coordinated operation of PSS and SSSC using ACO and PSO algorithm. A two area multimachine system is taken as test system which is analysed under various operating conditions. The coordination of PSS and SSSC using ACO ensures a more stable operation under various operating conditions.