This paper proposes a novel master-slave scheme to control active power of an HVDC system with multiple voltage-source converters. The total active power generated by three offshore wind farms (OWFs) based on doubly-fed induction generator is delivered to two onshore AC grids through the proposed HVDC system. The total active power sent to the two onshore AC grids can be equally shared by the proposed control scheme of the HVDC system under various operating conditions. Calculated system eigenvalues of the studied system at the nominal operating point are analyzed. Transient responses of the studied system subject to a three-phase short-circuit fault at one of the two power grids are also carried out. It can be concluded from the eigenvalues and transient simulation results that the proposed power control scheme is effective to stabilize the active power from the three OWFs sent to the two power grids under a severe disturbance condition using the proposed HVDC system.