Month: July 2025

Protection functions

REJ603 offers three-stage overcurrent and twostage earth-fault protection functions.

The transformer inrush detector function is incorporated to prevent unwanted tripping’s due to energizing of transformers.

The low-set stages for overcurrent and earthfault protection are equipped with selectable characteristics – Definite time (DT) and Inverse

definite minimum time (IDMT).

The relay featuresstandard IDMT characteristics according IEC 60255-151. Normal Inverse (NI), Very Inverse (VI),

Extremely Inverse (EI), Long-time Inverse (LI) and IDMT characteristics as per ANSI C37.112 Moderate inverse,

Normal Inverse, Very inverse, Extremely inverse.

The relay also has special characteristics like RI, HR and FR fuse,which allows better co-ordination with the rest of the network.

Further relay offers thermal overload protection for feeder, cable and transformer.

Description

REJ603 is a self-powered feeder protection

relay, intended for the protection of utility substations and industrial power systems, in secondary

distribution networks. REJ603 is a member of ABB’s Relion® product family and part of its 605 series.

The feeder protection relay REJ603 is designed to be a part of Ring Main Units (RMU) and secondary distribution switchgears.

The REJ603 relay is a self-powered numerical relay, which receives power from the main current transformers.

This way REJ603 is an ideal choice for installations where an auxiliary supplies are not available and hence is suitable

for unmanned distribution substations having no auxiliary supplies.

Relay has add-on optional function of remote trip through binary input with selection of auxiliary power version.

Relay functions

The relay provides an optimized composition of protection and monitoring functionality in one unit,

with the best performance usability in its class and are based on ABB’s in-depth knowledge of protection and numerical technology.

REJ603 offers pre-configured functionality which facilitates easy and fast commissioning of switchgear.

To emphasize the simplicity of relay’s usage, only application specific parameters needs to set within the relay’s intended area of application.

The relay also has short power up time which ensures fast operation during switch on to fault.

Supervision

To ensure continuous availability of protection, self-supervision of the relay hardware and software is incorporated. The

REF601/REJ601 and REM601 also include an integrated trip-circuit monitoring function which monitors the external trip

signal path. A built-in test mode which enables users to test the relay HMI, protection functions, and binary outputs.

The 605 series relays can store 100 events with time stamps at a resolution of 1 ms.

They can also store analog fault records for the last five trip events.

This data is stored in non-volatile memory.

The optional communication card extends local monitoring and control facility of the HMI to remote automation systems over

MODBUS RTU / IEC 60870-5-103 protocol.

Sensor support

These relays support both conventional CTs and Rogowski current sensors.

The sensor option helps to obtain equipment size reduction, performance improvement and better standardization in compact MV switchgear.

The REM601 offers protections for motors such as thermal overload protection,

short circuit protection, startup supervision, loss-of-phase protection, negative phase sequence protection,

ground fault protection, undercurrent protection and circuit breaker failure protection.

An emergency restart feature allows motor start up even when start inhibit is activated.

The residual current for CT configured relays is derived from the phase currents.

When applicable the zero sequence CT can be used for measuring residual current especially when sensitive

ground fault protection is required.

The REF601 integrates basic control functionality.

Apart from display of data and parameter settings, the user friendly local

human-machine interface (LHMI) supports control of one circuit breaker with dedicated control push buttons.

The LHMI display has built in support for multiple languages.

All three relays are equipped with a three level, role-based user authentication system with individual passwords for the operator, engineer and administrator levels.

Ease of use

The pre-configured functionality of relay facilitates easy and fast commissioning of switchgear.

Three dedicated and five configurable LEDs indicate the status of relay and protection functions while the 

LCD displays measurements, settings, events and recorded data. The relay can be set-up and configured entirely from the local HMI or with PCM600.

A single wide range auxiliary supply eliminates the need for ordering variance.

The relays also boast a press-fit mounting design for effortless installations on panels.

Configurable inputs and outputs are included which can be easily altered by the LHMI.

These relays incorporate detachable terminals with CT shorting which aids in improving MTTR (Mean Time to Repair) thus

further reducing downtime and improving productivity.

REF601/REJ601 and REM601 are members of ABB’s Relion® protection and control product family and its 605 series.

These relays provide an optimised composition of protection, monitoring and control functionality in one unit,

with the best performance and usability in its class.

The relay REF601/REJ601 offers various application configurations for Feeder protection and control while 

REM601 offers application configurations for Motor protection and control.

Protection and control

REF601/REJ601 offer three-stage overcurrent and two-stage ground fault protection functions.

The low-set stages for overcurrent and ground fault protection are equipped with selectable characteristics

– Definite Time (DT) and Inverse Definite Minimum Time (IDMT).

The relay features standard IDMT characteristics according IEC 61255-3 – Normal Inverse, Very Inverse,

Extremely Inverse, Long-time Inverse.

They also feature characteristics according to ANSI C37.112 – Moderate Inverse, Normal Inverse, Very Inverse, Extremely Inverse.

The relay has a special

characteristic RI Inverse (RI) for better coordination with the rest of the network.

Additionally the relays also support two setting groups.

Thermal overload protection for feeder, cable and transformer,

negative phase sequence protection phase discontinuity protection and circuit breaker failure protection are also offered.

An auto-reclose function for overhead line feeders is optional.

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.

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. 

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.

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.

Protection functions 

The REF601 and REJ601 offer three-stage overcurrent and twostage ground-fault protection functions. 

The transformer inrush detector function is incorporated to prevent unwanted tripping due to energizing of transformers.

The REF601 and REJ601 offer three-stage overcurrent and 

two-stage ground fault protection functions. 

The low-set stages for overcurrent and ground fault protection are equipped with 

selectable characteristics – Definite Time (DT) and Inverse Definite Minimum Time (IDMT). 

The relays feature standard IDMT characteristics according IEC 61255-3 – Normal Inverse, Very 

Inverse, Extremely Inverse, Long-time Inverse. 

They also feature characteristics according to ANSI C37.112 – Moderate Inverse, 

Normal Inverse, Very Inverse, and Extremely Inverse. 

The relays also have a special characteristic RI Inverse (RI) for better coordination with the rest of the network. 

Additionally the relays also support two setting groups.

The REF601 and REJ601 also offer thermal overload protection for feeders, cables and transformers. 

Other protections include negative phase sequence protection, phase discontinuity 

protection and circuit breaker failure protection. 

The relays also have an auto-recloser option for overhead line feeders.