Patent ID: 8334618
Filing Date: 2012-12-18
Classification: H02J,Y02E

Abstract:
1. An area electric power system comprising: a number of direct current power sources; a number of inverters operatively associated with the number of direct current power sources, each of said number of inverters being structured to provide real power and controlled reactive power injection to detect islanding; an output powered by said number of inverters; a number of electrical switching apparatus structured to electrically connect the number of inverters to and electrically disconnect the number of inverters from a utility grid; a number of devices structured to detect islanding with respect to the utility grid responsive to a number of changes of alternating current frequency or voltage of the output; and a resonant circuit electrically connected between said output and said number of electrical switching apparatus, wherein said resonant circuit is structured to not allow the alternating current frequency or the voltage of said output to drift when said number of inverters do not provide said real power and controlled reactive power injection of a sufficient amount to detect islanding.