A stabilization of frequency oscillations using a power modulation control of HVDC link in a parallel AC-DC interconnected system

When an interconnected AC power system is subjected to a large load with rapid change, system frequency may be considerably disturbed and becomes oscillatory. By utilizing the system interconnections as the control channels of high-voltage direct current (HVDC) link, the tie-line power modulation of HVDC link via the interconnections creates a sophisticated stabilization of frequency oscillations in AC systems. This paper takes this advantage of the HVDC link to implement a concept of frequency stabilization in interconnected power systems. A power modulation controller is designed based on stabilization of the inter-area oscillation mode. The techniques of overlapping decompositions and eigenvalue assignment are applied to establish the state feedback scheme of controller. Simulation study exhibits the significant effects of the proposed control