A bstract ： The paper intends to model the stability of power system with a deep learning algorithm to the problem, aiming to delay the removal of the fault. The so - called "fail - delay cut - off" refers to the occurrenc e of N - 1 backup protection action on the backbone network of the system, resulting in longer time for the removal of the fault. In practice, through the analysis and calculation of a large number of online data, we have found that the N - 1 failure system of the main protection action will not be unstable, which is also a guarantee of the operation mode arrangement. In the case of the N - 1 backup protection action, there is an approximately 2.5% probability that the system will be destabilized. Therefore, rese arch is needed to improve the operating arrangement.