The main wind power utilization characteristics in China are large scale development and centralized integration. Wind power resource is mainly distributed in North, Northwest and Northeast of China, where the conventional units are dominated by coal-fired units with poor regulation flexibility. Operation experience shows that wind power curtailment happens frequently in most of these systems. This problem indicates that current dispatch method cannot effectively adapt to the power system operation with high wind power penetration. Comparing with conventional units, the poor dispatch ability of wind farm is mainly due to its uncertain and variable power output. In order to make better use of wind farm cluster's spatial smoothing effect and develop its dispatch flexibility, this paper proposes the new idea of wind farm cluster virtual power generator (WVPG) based hierarchical coordinated real-time dispatch strategy. For the dispatch center, WVPG participates in real-time dispatch in the form of a partly controllable quasi-regular power source. For the internal wind farms inside a WVPG, WVPG is responsible for the coordinated dispatch of individual wind farm's power output. A virtual power generator based hierarchical coordinated real-time dispatch strategy for wind farm clusters is proposed in this paper. The effectiveness of this strategy is verified by simulation cases referring to real wind power base system in Northwest China.