The type DAD relay provides high-speed, high impedance, current differential protection with individual open-circuit monitoring of the CT secondary circuits. An advanced design input filter with a harmonic rejection circuit improves overall protection stability by rejecting the harmonics generated by the onset of CT saturation. The relay is provided with four output relays each with two contacts. Three of the relays, those normally associated with the alarm function, can be selected for latched/non-latched contact operation. Type DAD relay in a modular size 6 case