Impact of Two-Stage Service Restoration on Distribution Reliability

This paper examines the reliability improvements gained by using a two-stage restoration strategy rather than a single-stage restoration strategy following fault inception. In a two-stage strategy, a first stage quickly restores a limited set of customers using automated switches. A later stage restores additional customers using manual switches. The strategies are compared using a predictive reliability assessment algorithm capable of modeling each strategy. The impact of two-stage restoration is examined on a 10-MVA test feeder for various levels of feeder automation. Tests show that two-stage restoration significantly reduces customer interruption time for partially automated feeders. Further, single-stage restoration models underestimate the reliability benefits attainable through partial feeder automation.