The invention relates to a fault current detection device for an overhead power line. The fault current detection device is configured to apply a fault detection algorithm which includes a duration test and a return to normal test. The fault current detection device reports a fault current to a remote fault monitoring device only if both tests are passed. The fault monitoring device is configured to apply an alert ranking algorithm to determine which of a plurality of the fault current detection devices is closest to a fault. The alert ranking algorithm includes identifying or establishing a location of an upstream source associated with the fault current detection devices and classifying the fault current detection device which is the furthest downstream from the upstream source as the closest to the fault. A fault current detection method and a fault detection system and method are disclosed.