Evaluation of Delayed Input Effects to PSS Interarea Damping Control Design

Wide-area controllers have been proposed to enhance the dynamic performance of large interconnected power systems. The time delay existing in the data communication may be a detriment to wide area control system stability. This paper analyzes the effect of time delay on the additional interarea damping control (AIADC) design of PSS. The AIADC is proposed for generators´ excitation controllers and the wide area feedback control loop is chosen according to residue matrix. Pade approximation method is used to express time delay and state space model implying time delay is represented. The effect of delayed input signal is demonstrated by eigenvalue analysis and it can be diminished by using genetic algorithm (GA) to derive AIADC parameters. The effect of time delay on AIADC design is studied on a two-area four-machine system.