In this paper, a new controller design for a high-voltage direct current (HVDC) system subjected to frequency oscillation stabilization is proposed. The technique of overlapping decompositions is used to obtain the design subsystem embedded with the inter-area oscillation mode. The designed controller has the structure of a second-order lead/lag compensator. Automatically, the parameters of the controller are tuned based on a tabu search (TS) algorithm. The designed controller is installed in a three-area longitudinal interconnected power system. Consequently, the simulation results are carried out to illustrate the effectiveness of the designed controller.