The Future Role of Passive Methods for Detecting Unintentional Island Formation

AS increasing numbers of distributed generators (DGs) are deployed, utilities are becoming more concerned that these DGs may be able to support unintentional islands. Unintentional islands can be formed when any utility switching device isolates a portion of the area electric power system (EPS) that contains roughly equal amounts of sources and loads, and they potentially pose safety risks to personnel and integrity risks to customer equipment. Methods to detect the formation of unintentional islands can be subdivided into passive, active, and communications-based categories. Most DGs today rely on active methods, but unfortunately the time is soon coming when this approach will no longer work. The reason is because of the need for DGs to supply grid support functions as DGs, and these grid support functions interfere with the operation of active island detection. This means that in the future there will be a much larger role for passive and communications-based island detection