Based on a set of properly selected base values， a per-unit model for voltage source converter（VSC） based high voltage direct current（HVDC）（VSC-HVDC） is developed. With the proposed model， a novel generalized DC voltage control strategy is proposed in order to reduce DC voltage variation caused by system fault. The system can operate without communication between converter stations under this control strategy. An active power controller（APC） of outer loop can be treated as a generalized DC voltage controller（GDCVC）. When DC link voltage can not be maintained by the DC voltage controller（DCVC） for some reasons， the APC takes over the function of DCVC automatically and smoothly. So the variation of DC link voltage may be suppressed and safe operation of the VSC-HVDC system can be maintained. Therefore the capability of sustained operation can be enhanced with the help of GDCVC. Digital simulation shows the good performance of the proposed control strategy both at steady and transient conditions.