The HVDC supplementary control for AC/DC interconnected power grid based on hamilton energy function theory

Abstract

Low-frequency oscillation suppression of the interconnected power grid is an important factor for the stable operation of the power system. In this paper, the AC-DC interconnected power system is represented as the switched Hamilton system based on the centre of inertia (COI) equivalent method. The Hamilton energy function of the system is constructed from the viewpoint of the oscillation energy of the interconnected power system, which is then used as a uniform Lyapunov function to study the stabilization problem of the system. Then the high voltage direct current (HVDC) supplementary damping controller is designed aiming to reduce the oscillation energy thus the suppression of the oscillation is attained. The proposed control design procedure is fully based on nonlinear theory and can be widely used for practical power system with changing operation conditions. The feasibility of the proposed controller in the practical power system is discussed based on wide-area measurement system (WAMS). The simulation results of the EPRI 7 nodes system verify the correctness and effectiveness of the proposed method.