Patent ID: 8183714

Claim:
A power system comprising: a utility grid providing AC electric power connectivity and extending geographically to a plurality of first end-user locations and to a plurality of second end-user locations; the first end-user locations comprising more than one and less than all of the end-user locations of the utility grid; each of the first end-user locations comprising a local bus providing AC electric power connectivity; each local bus having associated with it at least one AC load metallically connected thereto and drawing power therefrom; each local bus coupled by means of a respective first at least one coupler to the utility grid, the at least one coupler comprising a first power-supply-inverter and a second power-supply-inverter; each power-supply-inverter having an AC interface and a DC interface and a controller; each power-supply-inverter disposed in a first mode to receive DC power received at the DC interface and to generate AC power delivered at the AC interface, and disposed in a second mode to receive AC power received at the AC interface and to generate DC power delivered at the DC interface; the DC interface of the first power-supply-inverter electrically connected to the DC interface of the second power-supply-inverter; whereby the at least one coupler has a first AC interface defined as the AC interface of the first power-supply-inverter and a second AC interface defined as the AC interface of the second power-supply-inverter; the controller of the first power-supply-inverter and the controller of the second power-supply-inverter coupled so as to prevent the first power-supply-inverter and the second power-supply-inverter from being in the first mode simultaneously for extended intervals, and so as to prevent the first power-supply-inverter and the second power-supply-inverter from being in the second mode simultaneously for extended intervals; each power-supply-inverter disposed when in its first mode to generate its AC power delivered at its AC interface consistent in voltage and phase and frequency with any AC power present external to said AC interface; the power system further comprising: a feeder providing AC electric power connectivity and extending geographically to the plurality of first end-user locations; each local bus coupled by means of a respective second at least one coupler to the feeder; the feeder being unsynchronized with the utility grid.