Method and apparatus for locating faults in an islanded microgrid

A method for locating and isolating an electrical fault in a microgrid disconnected from a wide-area electrical grid, comprising:

• providing a fault isolating device at each of a plurality of branches in the microgrid, each isolating device including a voltage meter for measuring voltage to detect an anomaly, a timer for establishing a time window, a switch for isolating a branch of the microgrid from power loads and power sources upstream of the isolating device, and a microcontroller for opening the switch during the unique time window and leaving the switch open when a measured voltage anomaly disappears;
• setting the time windows of each isolating device so that the time windows are non-overlapping;
• and
• opening the switch of each fault isolating device for the duration of the associated time window when a voltage anomaly is detected and either closing the switch if the voltage anomaly persists during the time interval or leaving the switch open to isolate a fault downstream of the isolation device if the anomaly disappears during the time interval.