An alternative method for mitigating impacts of communication delay on load frequency control

Abstract

Load frequency control (LFC) has been considered as one of the most important frequency regulation mechanisms in modern power system. One of the inevitable problems involved in LFC over a wide area is communication delay. Not only can the delay deteriorate the system performance but also cause system instability. In this paper, an alternative design method is proposed to devise delay compensators for LFC in one or multiple control areas. For one-area LFC, a sufficient and necessary condition is given for designing a delay compensator. For multi-area LFC with area control errors (ACEs), it is demonstrated that each control area can have its delay controller designed as that in a one-area system if the index of coupling among the areas is below the threshold value determined by the small gain theorem. Effectiveness of the proposed method is verified by simulation studies on LFCs with communication delays in one and multiple interconnected areas with and without time-varying delays, respectively.