PID damper design for wide‐area power systems considering time delays

Abstract

Wide-area damping control is able to improve the stability of interconnected power systems in case of low-frequency oscillations. Nevertheless, the damping effect is closely related to the time delay of wide-area control loops. The application potential of proportional-integral-derivative (PID) damper is explored in wide-area power system damping control. First, the relative residue index based on dominant oscillation modes is employed to determine a suitable control loop. Then, the PID stability space is calculated numerically based on extended Hermite-Biehler Theorem. Finally, the damping-robustness balance principle is discussed in the PID parameters selection. The proposed PID damper is tested by supplementing the generator excitation control in the two-area four-machine power system and the static var compensator control in the 16-machine 68-bus power system. Simulation results confirm that it is feasible to design a PID damper for the control loop with a larger relative residue index. The designed PID damper is able to enhance power system stability by inhibiting low-frequency oscillations under considerable time delays, and it is robust to the changes of system operation state and time delay.