With the continuous increase of the scale of wind power in China, it is important to look at the mechanism of the influence of large-scale wind power centralized access to the power grid on the transient power angle stability of the transmission system. An equivalent model is established as the research object for the centralized connection of the doubly-fed wind power to the large receiving end system. The analysis is carried out based on the transient characteristics and low voltage ride-through characteristics of the doubly-fed wind turbine. First, we adopt the electromagnetic power analysis expression of the synchronous machine of the single-ended power transmission system, and infer the influence of wind power connection on the initial power angle of the synchronous machine by analyzing the influence of wind power equivalent output replacement thermal power access system on the electromagnetic power equation. Secondly, through the comparison of the two access methods of negative load and wind power access, the influence of the active power and reactive power characteristics of the doubly-fed wind turbine on the electromagnetic power equation of the synchronous machine after the fault occurs is analyzed. Based on the equal area rule (EAC), the influence of the doubly-fed fan connection on the system transient power angle stability is analyzed. The results show that when wind power is equivalent to replacing thermal power output, the initial power angle of the synchronous machine decreases, and the transient stability increases; the active power and reactive power characteristics of the doubly-fed fan have a positive effect on the transient power angle stability of the system. Finally, the correctness of the theory is verified by simulation, and it is verified in the actual power grid. This work is supported by the Science and Technology Project of the Headquarters of State Grid Corporation of China (No. 5100-202116005A-0-0-00).