With the increasing grid-connected capacity and DC line of clean energy supply to the grid, the phenomenon of large-scale disordered off-grid of clean power connected to the grid after grid faults is aggravated. In this paper, based on the characteristics of different power supplies in the transmission network, the objective function and constraints of the off-grid capacity of the clean power supply of the power supply network are first defined, and then the operating conditions of the power supply base and the expected interval of the off-network capacity under different protection parameters are set. The coordination strategy of multi-power supply joint operation is formed. Finally, the simulation analysis of a large-area power grid shows that increasing the output of the conventional power supply near the clean power supply can alleviate the high-voltage off-grid phenomenon of cleaning the power supply in the event of grid fault. The solution of the safety control cutting machine and the high voltage traversing protection of the wind power under severe faults can effectively reduce the off-grid capacity of the clean power supply.