Coordinated control design of multiple HVDC links based on model identification

This paper presents a method for designing a centralized coordinated controller for several HVDC links. The controller increases the damping of the power oscillations by modulating the current through the HVDC links in a coordinated fashion. To design a centralized coordinated controller a reduced order open system model is estimated. The open system model of the power system is estimated using the Numerical Algorithms for Subspace State- Space System Identification (N4SID) algorithm which is a black-box system identification technique. The current set-point change through the HVDC links is the set of input signals and the speeds of the generators are the set of outputs. This controller design method increases the damping significantly, which is shown for a small power system.