processor 60 the resistances r 1 and r 2 may be selected so as to limit fault current through the neutral point 12 1 to specified values a sufficiently high value may be chosen for r 1 such that the fault current through the neutral point 12 1 may be limited to a maximum specified limit if a fault were to develop at a location far from the dc generator 16 or through some high impedance a high value of r 1 may restrict the fault current through the neutral point 12 1 to an insignificant level in such cases this fault current may be increased by closing the switch 34 which may connect the neutral point 12 1 to ground through a lower resistance r 2 the resistances r 1 and r 2 may be selected such that differential current sensors 50 around the fault may provide current differential signal to the processor 60 the values of r 1 and r 2 may be selected to suit a particular configuration of the system 10 in general r 2 may be about one tenth of r 1 it may be noted that for purposes of simplicity fig1 shows the processor 60 being connected to only one of the differential current sensors 50 in an actual embodiment of the invention all of the differential current sensors 50 may be connected with the processor 60 once a line ground fault is suspected by observing some line potential coming close to ground potential or abnormal voltages at any one or more of the test points switch 32 may be closed e g through activation by a.