Flexible alternative current transmission systems (FACTS) devices such as the hybrid unified power flow controller (HUPFC) can adjust the line power flow and effectively increase the transmission capacity of the transmission network. To solve the problems caused by the mechanical on-load tap changer (OLTC) used in the traditional HUPFC,a fast electromagnetic HUPFC based on full-power electronic OLTC is proposed in this paper. Firstly,the operation characteristics of HUPFC are studied,and a method to suppress the overvoltage generated in the switching process is proposed. At the same time,a tap selection strategy with the least switching times is realized by using the asymmetric stage voltage Sen transformer with the existence of degrees of freedom in the synthesis method of operating points,and the detailed steps from power flow instruction change to switching voltage regulation are given. Finally,the 220 kV double-loop circuit simulation model is built in Simulink,and the power flow regulation process and results of the fast electromagnetic HUPFC are compared with those of the traditional HUPFC. The results show that the full-power electronic switch has more advantages in response speed and reducing the power fluctuation in the adjustment process than mechanical OLTC,and the feasibility of the fast electromagnetic HUPFC is verified.