Wind power and UHVDC (Ultra-High Voltage Direct Current Transmission) have been widely used in China.Safety and stability of the power system are threatened by uncontrollable power flow transferring,which is caused by the fluctuation of bulk wind power or UHVDC blocking.Hence,it is of great significance for improving the stable of the power system by developing efficient power flow control devices.To solve the uncontrollable power flow transferring problem,control strategy of SSSC (Static Synchronous Series Compensator) is deduced,and electromagnetic transient model of SSSC is constructed as well.Results of the simulations show that the designed control strategy regulates the DC voltage effectively,and can control the power flow accurately and rapidly.This study is supposed to be helpful for the controller design of SSSC,and to be useful for the operating and power flow control of the power system with bulk new energy or UHVDC integrated.