Optimal Linear Quadratic Regulator Design of Interconnected Systems with VSP based HVDC Links for Inertia Emulation

Abstract

This paper proposes a new application for an optimal linear regulator for mitigation of frequency performance of an interconnected AC/DC system with (Virtual Synchronous Power) VSP based HVDC capabilities. The action of VSP, which is added into the HVDC control system, is to provide virtual inertia for the low-inertia system during a contingency. The proposed optimal regulator is designed to stabilize such ac/dc interconnected system while minimizing the associated cost function. For each of the presented controller, a different objective function is defined. This objective function is needed to tune the matrix gains and to process the optimum controller design. Simulations results demonstrate how the proposed regulator can significantly improve the reduction of frequency deviations and the damping of the interarea oscillations excited during a fault. This improvement is more obvious especially when a VSP-based virtual inertia emulation is activated in the system. 2019 IEEE.