Design of WAMS-Based Multiple HVDC Damping Control System

High voltage direct current (HVDC) links are interties, characterized by good controllability, large adjustable capacity and fast responses, and have inherent advantage in damping interarea oscillations over power system stabilizers (PSS) and flexible alternating current transmission systems (FACTS). In this paper, a systematic and practical means to design the multiple HVDC damping control system, which aims to enhance the damping of certain interarea modes and minimize the interactions between different control loops, is provided. In the proposed procedure, the wide-area feedback signals that have the good observability of target modes are preselected by an index based on residue analysis firstly. Then the interactions between the candidate control loops, in which the setting power reference of the HVDC as the input and the preselected wide-area signals as the output, are investigated by relative gain array (RGA) analysis. According to the RGA results, a suitable input-output pairing for multiple HVDC damping controller is determined. The transfer function residues used in the feedback signal preselection and the RGA calculation are identified by Prony analysis in the transient stability program and electromagnetic transient program respectively. Finally, the damping controller parameters are optimized by time-domain simulations. The application in China Southern Power Grid (CSG) is illustrated as the case study.