Study on Fast Stability of New Power System Based on the Method of Gradient Dynamic Deviation and PMU Data

Driven by dual promotions of energy transformation and scientific technology progress, the high proportion of renewable energy and power electronic equipment (Double-high) are becoming important trends and key features of the development of power system. The dynamic behavior of the power system has undergone major changes. The analysis method of the traditional small signal stability is difficult to use, which brings the great inconvenience to the subsequent calculation and analysis. Moreover, there are still problems to be solved for the rapid change of operating conditions, which puts forward higher requirements for the small interference stability analysis. In this paper, a Lyapunov direct analysis method of gradient dynamic deviation based on PMU data is proposed to analyze the small signal stability of the new power system. Firstly, a PMU data matrix is used to reduce the dimension to obtain the low dimension matrix, which is substituted into the power system matrix model with DFIG. Then, a diagonal matrix is obtained by solving the Lyapunov equation, and the positive definiteness of the matrix is determined to judge the system stability; Secondly, the dynamic deviation value of the corresponding state variable can be calculated by solving the diagonal matrix, and the extreme value of the curve can be calculated by using the gradient descent method for the corresponding state variable curve, and the time weighted dynamic deviation of the whole oscillation process can be calculated by time weighting, which provides guidance for the configuration position of the damping stability controller (PSS) in the system. Finally, the method can improve the small interference stability of the system and the effectiveness of the fast stability analysis of the new power system is verified by the IEEE 10-machine, and 39-bus system simulation.