ABB REF601 Feeder protection and control
1. Description
The REF601 is a dedicated feeder protection and control relay.
The REJ601 is an overcurrent protection relay without breaker
control. These relays are intended for the protection of utility
substations and industrial power systems within primary and
secondary distribution networks. They are members of ABB’s
Relion® product family and part of its 605 series.
These relays, provide an optimized composition of protection,
monitoring and control 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.
2. Relay functions
The REF601 and REJ601 can be pre-configured which facilita tes easy and fast commissioning of switchgear.
To emphasize the simplicity of using these relays, only applica tion specific parameters need to be set within the relay’s inten ded area of application. The standard signal configuration can
be altered by LHMI (local human-machine interface).
The relays are available in three alternative application configu rations, as indicated in Table 2.
Table 1. Standard configurations
Description Relay type
Feeder protection and control REF601
Overcurrent/Feeder protection REJ601
Table 2. Application configurations and supported functions
REJ601/ REF601 REJ601/ REF601 REF601
Functionality ANSI IEC B C D
Protection
Non-directional overcurrent protection, low-set stage 51P 3I> ● ●●
Non-directional overcurrent protection, high-set stage 50P-1 3I>> ● ●●
Non-directional overcurrent protection, instantaneous stage 50P-2 3I>>> ● ●●
Ground-fault protection, low-set stage 51N Io> ● ●●
Ground-fault protection, high-set stage 50N Io>> ● ●●
Three-phase transformer inrush detector 68 3I2f> ● ●●
Three-phase thermal overload protection for feeders, cables and
distribution transformers
49 3Ith> - ● ●
Phase discontinuity protection 46PD I2/I1> - ● ●
Negative-sequence overcurrent protection 46 I2> - - ●
Circuit breaker failure protection 50BF/50NBF 3I>BF/
Io>BF
- ● ●
Master trip 94/86 Master Trip ● ●●
Two setting groups ● ●●
Control (Function only available in REF601)
Breaker control functionality 52CB I <-> O CB ● ●●
Auto-reclosing, 4 shots 79 O -> I - - ●
Condition monitoring
Trip circuit supervision TCM TCS ● ●●
Measurement
Three-phase current measurement 3I 3I ● ●●
Residual current measurement IN Io ● ●●
Negative phase sequence current I2 I2 - - ●
Thermal level θ ϑ - ● ●
Operation counter - - - ● ●

3. Protection functions
The REF601 and REJ601 offer three-stage overcurrent and two stage 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 De finite 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 coor dination 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 inclu de negative phase sequence protection, phase discontinuity
protection and circuit breaker failure protection. The relays also
have an auto-recloser option for overhead line feeders.
4. Application
The REF601 and REJ601 are protection relays aimed at pro tection 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 sensiti ve ground-fault protection is required.
The application configuration C adds thermal overload protec tion for feeders, cables and transformers, phase discontinuity
protection and circuit breaker failure protection.
The application configuration D provides the highest functionali ty with incorporation of negative phase sequence protection and
a multi-shot auto-recloser function making the relay suitable for
overhead line feeders.
5. 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 accesso ries. Uniquely, the REF601 and REJ601 use a press-fit mounting
arrangement, suitable for quick and easy installation on switch gear
6. Control
The REF601 features control of one circuit breaker with dedica ted 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.
7. 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 suppor ted as per application configurations.
8. 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.
9. Recorded data
The relays store fault records of analog values for the last five
trip events in non-volatile memory. The fault recording is trigge red 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 ana lyze 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 sub sequent fault analysis.
10. Self-supervision and test function
The relay’s built-in self-supervision system continuously mo nitors 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 pro tection functions of the relay to prevent incorrect relay operati on.
The relays support a built-in test mode which enables the user
to test the relay HMI and binary outputs.
11. Trip-circuit monitoring
The trip-circuit monitoring continuously monitors the availability
and operability of the trip circuit. It provides open-circuit monito ring both when the circuit breaker is in its closed and in its open
position. It also detects loss of circuit-breaker control voltage.
12. 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 pass words 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.