High-Speed Communication-Assisted Tripping and Sectionalizing for Distribution Systems

The recent advent of Smart Grid has given rise to advances in communication systems for distribution systems. Modern numerical overcurrent relays have the technology available to utilize these communication channels for both high speed-assisted tripping and sectionalizing. Assisted tripping and sectionalizing allows the utility to operate their distribution system in a network as opposed to radial feeders. A networked system is much more reliable and customers experience fewer outages since there are multiple sources readily available. Assisted tripping and sectionalizing quickly isolates the fault and eliminates the need for long clearing times and complex coordination typically associated with classical time overcurrent protection. This paper demonstrates how to apply communication-assisted tripping and sectionalizing, taking into account specific considerations for distribution systems not necessary for transmission applications-for example, a feeder with distributed generation connected. Several detailed examples are presented as to how to implement these schemes for typical distribution systems. This paper also gives specific settings and operational details of these schemes. Additionally, a review of the operational history highlights the impact that these schemes have on the reliability of the utility distribution network.