Development and Integration of Momentary Event Models in Active Distribution System Reliability Assessment

The random failures in a distribution network lead to different reliability events, such as voltage sags, momentary interruptions, and sustained interruptions. Even momentary reliability events i.e., voltage sags and momentary interruptions cause significant financial losses to many customers. This paper develops a novel aggregated reliability event model for the reliability studies of distribution systems integrating the momentary reliability events in addition to sustained interruptions. The developed model incorporates the impacts of temporary and permanent failures on the customers considering different reliability events. A graph theory-based search algorithm is utilized to efficiently recognize different protection settings, alternate supplies, and presence of Distributed Energy Resources (DERs)/microgrids in the network. Furthermore, the proposed model incorporates the possible mitigation measures brought by the DERs/microgrids while quantifying the reliability profile of load points and the overall system. The case studies conducted on a practical test system show the effectiveness of the proposed model to evaluate the reliability and to carry out system upgrades in the context of active distribution systems.