Abstract: The calculation of total power supply capability is an important issue in the planning of a partitioned flexible interconnected power grid. With a large number of renewable energy connected to the grid, the problem of dynamic voltage instability is becoming more and more prominent. The nonlinear characteristics of the maximum power supply capacity calculation model are obvious considering dynamic voltage stability constraints, which brings about great challenges to the model solution. Firstly, by analyzing the dynamic voltage stability with the improved small disturbance analysis, the mathematical model of the total supply capability is established considering the dynamic voltage stability indexes. Secondly, the calculation framework of the maximum power supply capacity is given based on the deep deterministic strategy gradient algorithm, designing the action and state space, reward function, neural network and learning process of the model. Finally, taking a power grid as an example, this method can optimize the calculation of the maximum power supply capacity while effectively avoiding the dynamic voltage instability of the interconnected power grid.