Yasaman Yardani Sefidi - Electric Power Dep., Faculty of Electrical and Computer Engineering, Islamic Azad University, North Tehran Branch, Tehran, Iran.
Rasoul Asghari - Electric Power Dep., Faculty of Electrical and Computer Engineering, Islamic Azad University, North Tehran Branch, Tehran, Iran.
Babak Mozafari - Electric Power Engineering Dep., Faculty of the Electrical and Computer Engineering, Islamic Azad University, Science and Research Branch, Tehran, Iran
Mohammad Salay Naderi - Electric Power Dep., Faculty of Electrical and Computer Engineering, Islamic Azad University, North Tehran Branch, Tehran, Iran.

As opposed to the existing approaches which recognize communication network time delays, when they are introduced into the feedback signals, as a main cause of instability or poor performance in power system wide-area damping controller (WADC), this paper shows that if time delay in feedback loops is properly determined, the WADC performance to damp out inter-area oscillations will be improved. In other words, in situations where it is not easy to design and implement the WADC for Flexible AC Transmission Systems (FACTS) devices without delay, in order to effectively compensate the delay, in this paper, a new Wide-Area Damping Controller Delay Effect (WADCDE) is designed. First the model of power system with delay as a design parameter is established. Then, the WADCDE based on objective function of the rightmost real part of eigenvalues is designed and the sufficient condition about stability of the closed-loop system is given. A four-machine power system for numerical simulations has been used to evaluate the accuracy of the proposed control function and the feasibility study. The simulation results showed that the controller designed in a wide range of delay feedback reduces the oscillation of power system without restricting TCSC operation.

Stabilizing Delay Effect Problem, Power Oscillation Damping, Delay Scheduling