Abstract: With the rapid growth of the scale of distributed photovoltaic and other new energy connected to the grid, it brings severe challenges to the new energy power convergence, evacuation, consumption and power grid flow optimization control. The flexible AC transmission system device based on power electronics technology can effectively improve the transmission capacity of the transmission network. The hybrid unified power flow controller composed of high-capacity Sen transformer and small-capacity unified power flow controller can effectively improve the economy of the device on the basis of realizing the continuous regulation of power flow, and has a good application prospect. In order to ensure the accuracy and reliability of HPFC power flow regulation, we gave the capacity allocation method of HPFC and the determination method of main circuit parameters. In order to solve the problem of coordination of response speed between ST mechanical on-load tap changer and UPFC power electronic switch, we proposed a power flow control strategy based on predictive current control, and built the 220 kV double-circuit circuit and three-machine nine-node system in Simulink for simulation. The simulation results show that the HPFC capacity allocation method is correct and effective, and the predicted current control strategy can reasonably calculate the tap position, slow down the impact of transition current on the HPFC control system, and make the system power quickly adjust to the target value.