A new reliability assessment approach for integrated energy systems: Using hierarchical decoupling optimization framework and impact-increment based state enumeration method

A new reliability assessment approach to Integrated Energy Systems (IESs) is introduced in this paper. The optimal load curtailment (OLC) algorithm and reliability assessment algorithm are both improved in the proposed approach. For the OLC problem, this paper develops a hierarchical decoupling optimization framework for both the energy hub optimal dispatch and the optimal power flow problems. This feasible solution can make the OLC calculation more efficient and accurate. For the reliability assessment algorithm, an impact-increment based state enumeration (IISE) method is accommodated for IESs to accelerate the reliability assessment process. Also, a reduction technique of higher order contingencies is presented for the reliability evaluation of IESs to further enhance the computational efficiency. Case studies are performed on an IESs test case combined the IEEE-33 bus system with 14-node gas system and a practical case combined the IEEE 118-bus power system with Belgian natural gas network Numerical results demonstrate the efficient and robust performance of the proposed approach. Besides, the impacts of energy conversion process and energy hubs on IESs reliability are analyzed in detail.