ABB REJ603 Self-Powered Feeder Protector

The REJ603 relay is used for selective short-circuit and earth-fault protection of feeders in secondary distribution networks, as well as for transformer protection in utilities and industry.

The relay is a self-powered digital relay that does not require an external auxiliary supply voltage, making it ideal even for installations in remote areas where auxiliary power is not available.

The relay operates from a current transformer.

The REJ603 is mainly used in Ring Main Units (RMUs) in distribution networks.

The relay provides earth current measurement by internal calculation, or it can measure earth current from an external core balanced current transformer (CBCT).

The main features of the relay are

Self-powered three-phase non-directional overcurrent and earth fault protection with DMT and IDMT characteristics

Dual earth fault measurement modes - internal vector summing or external CBCT inputs

Integration of IDMT curves (IEC and special) in a single product to meet the time-coordinated requirements of secondary distribution protection

Protection blocking via second harmonic measurement to ensure stability during transformer magnetic surges

Capacitive discharge pulse output for low-energy trip coils

Built-in manual reset electromechanical sign for trip indication

Easy setup via DIP switches, protected by transparent cover

Compact design and mounting for ring main unit (RMU) applications

Test equipment for testing the entire program, including primary CTs, relays and trip coils

Operating instructions

The combined overcurrent and earth fault relay is a secondary relay that is connected to the current transformer of the protected object.

In addition to the measurements (inputs), the relay receives from the current transformer the energy required for its own operation and for tripping the circuit breakers.

There are two LEDs on the front panel. The green “Ready” indicator lights up when the minimum current required for operation is available, indicating that the relay is operating.

When a fault is detected, the relay will trip the circuit breaker according to the setting.

The relay will also perform periodic internal health checks and notify the user of any faults within the relay.

Internal relay faults are indicated by the red LED “IRF” indicator.

The overcurrent device will operate when the phase current exceeds the set run time for timed operation or the calculated run time for inverse time limit operation.

Operation. Similarly, the high level I>> of the overcurrent device will actuate when the set operation time has expired.

The ground fault unit operates when the ground fault current exceeds the set operation time for timed operation or the calculated operation time for inverse time limit operation.

Similarly, the high level I0>> of the ground-fault unit operates when the set operation time expires.

The low-level rectification stage of the overcurrent unit and the low-level rectification stage of the ground-fault unit can have a deterministic time or inverse deterministic minimum time (IDMT) characteristic.

When the IDMT characteristic is selected, four standard time/current curves and three special time/current curves are available.

The standard curves conform to BS142 and IEC 60255 and are referred to as normal inverse time, extreme inverse time, extreme inverse time and long time inverse time.

In addition, three special curves are available, namely the RI curve, the HR fuse curve and the FR fuse curve.