  Advances in microgrids powered by Distributed Energy Resources (DERs) make
them an attractive response capability for improving the resilience of
electricity distribution networks (DNs). This paper presents an approach to
evaluate the value of implementing a timely response using microgrid operations
and DER dispatch in the aftermath of a disruption event, involving strategic
compromise of multiple DN components. Firstly, we extend the resiliency
assessment framework in [1] and develop a sequential (bilevel) model of
attacker-operator interactions on a radial DN with one or more microgrids.
Particularly, the operator response includes microgrid operations under various
islanding configurations (regimes), and single- or multi-master operation of
DERs in providing grid-forming services as well as frequency and voltage
regulation. Secondly, we introduce a restoration problem in which the operator
gradually reconnects the disrupted components over multiple periods to restore
the nominal performance of the DN. The first problem, formulated as a bilevel
mixed-integer problem, is solved using a Benders decomposition method. The
second problem, formulated as a multi-period mixed-integer problem, can be
solved using a greedy algorithm. Our results illustrate the benefit of using
microgrids in reducing the operator's losses, both immediately after the
disruption event and during the restoration process.
