The circulating current relay IRXm is mainly used for high-speed restricted earth fault protection of generators and transformer windings. For the selective detection of faults, current transformers in summation connection are employed with an external stabilizing resistor for high impedance method of measurement. The relay is provided with a band-pass filter which suppresses harmonics and DC components of the input current. The relay is suitable for current transformers with secondary rating of both 1A and 5A.