An Eigenvalues Method for Stability Analysis of Power Grid with Energy Storage Devices Based on Discrete Time Domain Model

Abstract

The eigenvalue analysis based on state space model is an important method to study stability of power grid. With the large-scale access of energy storage devices and power electronics converters in power grid, the conventional state space modelling method suffers from complicated process of determining state variables and large calculation amount of eigenvalues, and nonlinear stability characteristics of power grid cannot be accurately reflected. To obtain the eigenvalues of power grid with energy storage devices more efficiently, this paper proposes a method for constructing state space model of power grid based on discrete time domain model (DTDM) and presents the corresponding stability criterion. Compared with the conventional state space modelling method, the nonlinear characteristics of components under proposed method can be linearized, and the constructed state space model can capture a wider range of system information including energy storage devices. Besides, the complete state space model of power grid can be obtained only according to the connection between component's DTDM and grid. Moreover, because eigenvalue solution under proposed method relies on the sparse grid node voltage matrix, the calculation of eigenvalues is simple and efficient, and it visually presents variation trend of eigenvalue and investigates the stability of system. Simulation results in Simulink/Matlab verify the correctness and effectiveness of proposed method.