Negative sequence current relays are primarily applied to protect generators and motors from dangerous overheating due to unbalanced currents. They are also used in transmission systems to detect unbalanced conditions and faults. RXIIK 4 is a modern microprocessor based negative sequence overcurrent relay. The relay has the possibility of setting a fixed time or an inverse time overcurrent characteristic.
Two setting levels are available for alarm and tripping. Two setting groups are available and can be selected via binary input or the front HMI. RXIIK 4 comprises a transformer isolated input unit for the three-phase current, a microprocessor based measuring unit and the front accessible HMI unit. The RXIIK 4 requires auxiliary DC power fed from a universal 24-250 V DC/DC converter type RXTUG 22H. RXIIK 4 has five programmable output relays, which can be independently selected to operate from any of the included functions in the relay. It is possible to have several outputs operated from one function. There are six available functions that can be selected for these outputs;
I - Start
I - Alarm
I - Trip
Group 2 settings active