This paper proposes a new application of Static Synchronous Series Compensator (SSSC) to stabilization of frequency oscillations in a multi-area power system. To stabilize the frequency oscillations, the dynamic power flow control of the Static Synchronous Series Compensator (SSSC) located in series with the tie line between interconnected power systems, is employed. By regarding the system interconnection as a control channel, the power flow control by an SSSC via the interconnection creates a sophisticated method of frequency stabilization. To implement this concept, the robust design method of lead/lag controller equipped with the SSSC is used. SSSC is located in two different areas and the best location for compensation is shown. The technique of overlapping decompositions is applied to reduce the order of the study power system; meanwhile the physical characteristic is still preserved. Simulation study exhibits the significant effect of designed controller on the study four-area interconnected power system under different load disturbances.