Application of switched system theory in power system stability

The conventional switched system generally designs switched control actions to switch between different subsystems to make sure a stable global system. In this paper, the author focuses on how to apply switched system methodologies to analyze stability of power systems, especial for power systems under faults. The recent development in stability analysis and control design of switched systems is surveyed at first. Secondly, the model of a switched power system is introduced, and multiple Lyapunov functions (MLF) are defined for power systems under different stages caused by faults. A new method depending on MLF is introduced to find the critical clearing time (CCT). Finally, the proposed approach is verified by simulation test based on a single machine infinite bus (SMIB) power system. The result presented in this paper demonstrates that the power system can be regarded as an aggregation of a number of switched subsystems and the corresponding stability can be analyzed by MLF.