As a mature power flow control device, power phase shift transformer can effectively balance the power flow distribution and improve the power supply capacity of power grid. It also has the advantages of low investment cost and high operation reliability. Firstly, the structure characteristics of phase shift transformer and the principle of power flow control are analyzed. Then, based on the real-time digital simulation platform, the detailed electromagnetic transient model of dual core symmetrical phase shift transformer is established. The power flow fluctuation and the control characteristics of the phase shift transformer are studied under the put-in situation and the power flow regulation mode respectively. The results show that the proposed model can effectively control the power flow distribution. Finally, according to the actual operation situation of power grid, the application scenarios of phase shift transformer in power grid are summarized, which provides reference for the large-scale application of power flow control technology in China's power grid.