This paper proposes a multi-time collaborative restoration model for integrated electricity-gas distribution systems (IEGDSs) considering multiple resources after extreme weather events. Based on the linearized power flow constraints of the unbalanced electrical distribution system (EDS) and gas distribution system (GDS)

this problem can be formulated as a mixed-integer linear programming (MILP) model. To improve the efficiency and veracity of the solution

a rolling optimization based two-stage method is developed with the first stage solved by a linear approximation model

and the second stage solved by real-time updated rolling optimization. By solving the MILP problem using rolling optimization

the proposed model and solution method achieve efficient and reliable collaborative restoration of IEGDS considering multiple resources and unbalanced operation characteristics of EDS. The effectiveness of the proposed model and method is validated by using an IEGDS made of a 37-bus unbalanced EDS and 11-node GDS.