Applying self-healing schemes to modern power distribution systems

Self-healing schemes in the context of power distribution systems have the objective of performing fault location, isolation, and service restoration in an automated fashion, i.e., without (or with limited) distribution system operator and repair crew intervention. Some of the intrinsic benefits of this smart distribution technology are increased reliability due to outage duration reduction, more efficient use of personnel and resources (crews, operators, vehicles, etc), and increased operational flexibility. Reliability is naturally increased since less time is needed for locating and isolating faulted feeder areas, as well as for restoring customers located on healthy feeder sections. Self-healing schemes are an inherent part of the Smart Grid and are expected to play a fundamental role in modern and future distribution systems. It is worth noting that the switchgear technology (protective and switching devices, including adaptive protection), sensors, enterprise systems and communications infrastructures required for the implementation of self-healing schemes represent the basis for the execution of other smart distribution applications such as automated system reconfiguration and optimization. Therefore, a growing number of self-healing projects are being implemented by utilities as part of their power delivery modernization plans. This paper discusses the estimation of reliability benefits of self-healing schemes, with emphasis on Fault Location, Identification and Service Restoration (FLISR) applied to real distribution feeders.