With the commissioning of Xiamen flexible HVDC transmission system, Fujian power grid has become an AC/DC hybrid power grid with voltage source converters. This paper presents an optimal reactive power flow model with voltage source converters, which is solved by branch and bound method and primal dual interior point method. The proposed model and related solving method have been tested on the automatic voltage control (AVC) system of Fujian power grid. The optimal control policies on generators, capacitors, reactors, OLTCs, and voltage source converters are calculated online, and the control performance is satisfactory. This work is supported by National Natural Science Foundation of China (No. 51377143).