The 2V68 is a three phase monitoring device designed to provide continuous supervision of the CT circuits in high impedance differential protection schemes. The relay will detect open circuit conditions in the CT summation wiring and open circuited main current transformers.

The 2V68 type relays have a setting range of 2-14V adjusted on a per phase basis from calibrated potentiometers at the front panel. The relay is continuously rated at 300V RMS & no external resistors are required. An optional harmonic filter is available to reject 2nd, 3rd, 4th and 5 th harmonics to reduce the effect of switching transients.

The AC input is continuously monitored & when it exceeds the pre-set level. Latching contacts are actuated after a three (3) second time delay. An optional adjustable time delay setting version may be specified. Three (3) latching contacts are intended to be connected across the buswires of the busbar protection to provide shortcircuiting of the busbar protection relay on detection of an open circuit condition. The remaining three (3) latching contacts are available for alarm & signalling functions.

Operation of the relay is indicated by a hand reset flag. A switchmode power supply provides a very wide auxiliary operating range. A relay fail alarm is provided in the form of a C/O contact which is picked up when the auxiliary supply is healthy.