Apparatus and method for detecting a fault in a distributed line network

Abstract

The present invention provides an arrangement for automatic selective circuit interruption in response to detection of a fault in a multi-phase distribution system feeding a plurality of network branches. The arrangement includes a plurality of line monitoring devices which are programmed to alarm a control station in response to detection of a fault in the system. In response to being alarmed by one or more line monitoring devices, the control station activates a specialized signal generator which produces a specialized signal along one of the lines of the multi-phase system. Each line monitoring device is co-located with and communicatively coupled to a circuit interrupter which, when actuated, prevents the flow of current in lines of the system positioned downstream from the actuated circuit interrupter. Each line monitoring device automatically actuates the coupled circuit interrupter within a prescribed period of time following detection of the specialized signal. By making the prescribed actuation time period longer for upstream circuit interrupters than downstream circuit interrupters, the network may continue providing power less an isolated section having the ground fault. The one or more line monitoring devices which detect the specialized signal inform the control station of the location of the fault.