Abstract
A microgrid is a group of interconnected loads
and distributed energy resources. It can operate in either gridconnected
mode to exchange energy with the main grid or run
autonomously as an island in emergency mode. However, the
transition of microgrid from grid-connected mode to islanded
mode is usually associated with excessive load (or generation),
which should be shed (or spilled). Under this condition, this
paper proposes an robust load shedding strategy for microgrid
islanding transition, which takes into account the uncertainties
of renewable generation in the microgrid and guarantees the
balance between load and generation after islanding. A robust
optimization model is formulated to minimize the total operation
cost, including fuel cost and penalty for load shedding. The
proposed robust load shedding strategy works as a backup
plan and updates at a prescribed interval. It assures a feasible
operating point after islanding given the uncertainty of renewable
generation. The proposed algorithm is demonstrated on a
simulated microgrid consisting of a wind turbine, a PV panel,
a battery, two distributed generators (DGs), a critical load and
a interruptible load. Numerical simulation results validate the
proposed algorithm.
