Microgrid Operation Scheduling: Ensuring Frequency Stability for Seamless Islanding

Solar microgrids (MGs) offer numerous benefits, including sustainability and reliability. However, frequency security concerns arise following unscheduled islanding events. To address this, a frequency-constrained solar microgrid scheduling model is proposed to achieve seamless islanding. First, the frequency dynamics of solar MGs post-unscheduled islanding are modeled, with primary frequency response approximated as linear delivery to derive convex frequency constraints. Then, rate of change of frequency (RoCoF), maximum frequency deviation (MFD), and quasi-steady-state frequency deviation (QSSFD) constraints are embedded into the scheduling model, and PV plant uncertainties are managed using a distributionally robust chance-constrained (DRCC) method based on inexact moment information. The non-convex distributionally robust chance constraints are reformulated into second-order cone constraints. Case study demonstrates that the proposed scheduling model ensures the frequency security of solar MGs under unscheduled islanding and effectively manages PV plant uncertainties through the DRCC method. This study provides valuable insights for the secure and economic operation of solar MGs.