Small-Signal Stability Analysis of Microgrid Based on Perturbation Theory

This paper presents a perturbation based method for small-signal stability analysis in microgrid based on the uncertainty of microgrid parameters. The small-signal state-space model is built including the dynamic characteristics of the controllers, the power measurement and the system circuit and load dynamics model. The system eigenvalues of operating point at a steady-state in microgrid are obtained by the model. Based on perturbation theory, the corresponding low-frequency eigenvaluea and damping ratio of the microgrid system are calculated when the microgrid parameters changing in the range. Then the relationship between small-signal frequency stability and parameters changes can be determined. The validity of the proposed method and the importance of the stablility analysis of the microgrid small-signal are proved by the simulation results.