This case study presents results of Hydro-Québec’s construction and testing of an anti-islanding approach, referred to as an autoground. The premise of the approach is to allow the distributed generation system time to detect the islanding situation. This is done using a passive approach up until the moment just prior to reclosing of the substation breaker, at which point the autoground momentarily short circuits the feeder, forcing any remaining distributed generation resources to disconnect based on line protection.
The autoground approach was proposed by Hydro-Québec in the context of the IEEE 1547.8 recommended practices working group.
The authors address considerations of implementing autoground technology, focusing on its incorporation with an existing distribution protection philosophy, construction in partnership with manufacturers, and establishing open dialog with distribution generation proponents.