A Transient Stability Assessment Framework in Power Electronic-Interfaced Distribution Systems

This paper introduces a framework of transient stability assessment for future distribution systems that are comprised of multiple microgrids. Enabled by the advances in power electronics and synchrophasor technologies, an angle droop method is introduced for autonomous real power sharing among coupling-operated microgrids. In our previous work, the small-signal stability criterion are derived. It is well-known that only regional transient stability can be established for conventional multi-machine systems interfaced with synchronous generators. In contrast, we show in this paper that asymptotical stability in the large can be achieved if angle droop method is adopted for real power sharing among coupled microgrids. Transient stability criterion is derived by formulating the linear matrix inequality (LMI) version of the Kalman-Yakubovich-Popov (KYP) conditions corresponding to the multi-variable Popov criterion. Numerical studies show the effectiveness of the proposed transient stability assessment framework for future power electronic-interfaced distribution systems.