New high voltage direct current (HVDC) installations are expected to be able to provide stability support to the main synchronous networks to Which they are connected. In multi-terminal HVDC (MTDC) schemes incorporating offshore wind farm this issue could be addressed by setting aside a reserve of wind energy by the curtailment of wind turbine generators (WTGs). This paper proposes a communication-less dc voltage cooperative control strategy for MTDC transmission systems. A grid side converter, the master, and a wind farm are designed to work cooperatively to maintain a stable dc link voltage, facilitating normal power dispatch orders and the provision of frequency support. The proposed control maintains a wind energy reserve and uses a flexible dc link voltage at the master converter. Allowing the local master dc voltage to vary within certain limits encourages the wind farm to participate in dc link voltage control and hence no communication system is required. The master converter automatically assumes control of the dc link voltage in the absence of wind or when the wind reserve is used up. A four terminal MTDC system comprising one master converter, two active/reactive power converters and one wind farm is studied. The effectiveness of the proposed control strategy is validated through simulation using MATLAB((R))-SIMULINK (R). (C) 2017 Elsevier Ltd. All rights reserved.