MFAC relays provide high-speed differential protection for various types of power system plants including generators, reactors, busbars, motors and the individual windings of power transformers. MFAC relays are fast and reliable due to simple electromechanical construction and operate as a high impedance unit protection scheme with a wide range of setting.

Two versions for phase and earth fault protection

The MFAC relay operates as a high impedance unit protection scheme, with settings determined by a series of resistors. The resistors are selected on a seven-way plug bridge.

MFAC 14, a single element version, is applied only when earth fault protection is required. MFAC 34, comprised of three elements, provides both phase and earth fault protection.

Wide settings range with a simple, robust design

Ensuring high stability with through faults, MFAC relays benefit from a simple application technique. With 'tuned to rated frequency' and a wide settings range, the MFAC has a robust and straightforward design.