To provide a DC ground fault detecting relay having a function of identifying a ground fault line.

The DC ground fault detecting relay 10: includes a ground fault power supply 11, a coupling capacitor 12, an N-pole selecting switch 13N, a P-pole selecting switch 13P, first and second resistances 141and 142, and first to third switches 151to 153as AC voltage supply instruments which apply an AC voltage to a main line of a DC cable run when a ground fault accident occurs; includes an AC power supply 41, a variable coil 42, and a current eliminating switch 43 as earth capacitance current eliminating instruments which eliminate an earth capacitance current included in an AC ground fault current that flows through each of a plurality of branch lines branching from the main line when an AC voltage is applied to the main line; and includes an input selecting unit 31, a calculating unit 32, and a display unit 33 as ground fault line identifying instruments which identify a ground fault line based on an AC ground fault current from which an earth capacitance current is eliminated by the earth capacitance current eliminating instruments.

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