ABB REJ601 Application Overcurrent/Feeder protection

Application 

The REF601 and REJ601 are protection relays aimed at protection and control of incoming and outgoing feeders in MV distribution substations. 

They can be applied for short-circuit, overcurrent and ground-fault protection of 

overhead lines and cable feeders of distribution and sub-distribution networks.

The inrush current stabilization function allows the relays to be 

used as the main protection for distribution transformers.

The relay with application configuration B offers non-directional 

overcurrent and ground-fault protection. The residual current for 

the ground-fault protection is derived from the phase currents. 

When applicable, core-balance current transformers can be 

used for measuring the residual current, especially when sensitive ground-fault protection is required.

The application configuration C adds thermal overload protection for feeders, cables and transformers, phase discontinuity 

protection and circuit breaker failure protection.

The application configuration D provides the highest functionality with incorporation of negative 

phase sequence protection and a multi-shot auto-recloser function making the relay suitable for overhead line feeders.

Optimized for limited space

With their compact size and unique technical features, the 

REF601 and REJ601 are ideal for retrofits, compact switchgear 

and switchgear with limited space. These relays have a small 

mounting depth and do not have any loose mounting accessories. 

Uniquely, the REF601 and REJ601 use a press-fit mounting 

arrangement, suitable for quick and easy installation on switchgear

Control 

The REF601 features control of one circuit breaker with dedicated push-buttons and guidance on local HMI for opening and closing. 

It includes two dedicated outputs for breaker control. 

The breaker control is also possible through optional MODBUS RTU or IEC 60870-5-103 communication.

Measurement 

All versions of the relay continuously measure phase currents 

and ground current. Ground current can be measured using an 

external zero sequence current transformer or can be calculated internally.

During operation, the default view of display shows the highest 

loaded phase current in primary terms (Amps) and the ground current. 

The values measured can be accessed locally via the 

user interface on the relay or remotely via the communication interface of the relay. 

These relays continuously measure negative sequence current, 

thermal level and counter values if these functions are supported as per application configurations.

Event log 

To collect sequence of events (SoE) information, the relays 

incorporate non-volatile memory with a storage capacity of 100 

events with associated time stamps and a resolution of 1 ms. 

The event log includes trip circuit monitoring status, protection 

operation status, binary I/O status and relay fault code. 

The event logs are stored sequentially, the most recent being first and so on. 

The non-volatile memory retains its data in the event of temporary auxiliary supply loss. 

The event log facilitates detailed post-fault analysis of feeder faults and disturbances. 

The SoE information can be accessed locally via the user interface on the relay front panel or remotely 

via the communication interface of the relay. 

Recorded data

The relays store fault records of analog values for the last five trip events in non-volatile memory. 

The fault recording is triggered by the trip signal of a protection function. 

Each fault record includes the current values for three phases and ground current along with a time stamp. 

These records enable the user to analyze the five most recent power system events. 

The relays record the number of phase and ground fault trip events into dedicated trip counters. 

These trip counters cannot be reset by the user and are stored in non-volatile memory. 

The recorded information can be accessed locally via the user interface on the relay front

panel and can be uploaded for subsequent fault analysis. 

Self-supervision and test function 

The relay’s built-in self-supervision system continuously monitors the state of the relay hardware and the operation of the relay software. 

Any fault or malfunction detected will signal an alert for the operator. 

A permanent relay fault will block the protection functions of the relay to prevent incorrect relay operation. 

The relays support a built-in test mode which enables the user to test the relay HMI and binary outputs.

Trip-circuit monitoring

The trip-circuit monitoring continuously monitors the availability and operability of the trip circuit. 

It provides open-circuit monitoring both when the circuit breaker is in its closed and in its open position. 

It also detects loss of circuit-breaker control voltage.

Access control 

To protect from unauthorized access and to maintain the integrity of information, the relays are armed with a three level, 

role-based user authentication system with individual passwords for operator, engineer and administrator levels. 

There are two alternative password protection options. 

The default is a combination of different navigation keys. 

The alternative is an alpha-numeric password. 

The user can select the password option based on their requirement.