Method to Recognize Vulnerable Area based on the dynamic analytic in complex domain

The growth of grid scale leads to the increasing coupling degree of the power grid, which makes the characteristics more and more complicated. Therefore, the traditional modeling method is difficult to calculate the degree of coupling relationship between each node. In power system, the change of vulnerable area only can be judged by extensive calculation experience. In this paper, the voltage stability affected (VSA) index contains the dynamic impedance matrix, the VSA can be used to reflect the electrical coupling relationship between different regions, and quantify the electric coupling degree of the whole power network. When a fault occurs in a vulnerable area, it will have a greater impact on the system. Therefore, a dynamic analysis method based on complex domain is proposed to identify vulnerable areas under different conditions. This method provides a convenient method to analyze the interference effect and the dominant factor. The results show that the method is reasonable and effective.