ABB
5
1MDB07207-YN
Feeder Protection
REF601
Product version: 2.0
coil is not current, but a voltage. Due to absence
of ferromagnetic core, the sensor is linear up to the
highest currents.
The wide measurement range of sensors with high
accuracy eliminates the need for high variants of
conventional instrument transformers, resulting in
simplified engineering, logistics and reduced inven-
tory. The low level voltage signals and integrated
secondary cables contribute to easy and fast instal-
lation with enhanced safety.
6. Control
The relay offers 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 communi-
cation.
7. Measurement
The relay continuously measures phase currents
and earth current. Earth current can be measured
using external core balance current transformer or
can be calculated internally.
During service, the default view of display shows
the most loaded phase current in primary terms
(Amps) and the earth current in terms of nominal
value of CT. The values measured can be accessed
locally via the user interface on the relay or remotely
via the communication interface of the relay.
To maintain the measurement accuracy of the
overall protection system, the sensor calibration
constants available on the rating plate of sensors
can be programmed to the relay.
8. Event log
To collect sequence-of-events (SoE) information,
the relay incorporates a non-volatile memory with a
capacity of storing 100 events with associated time
stamps with resolution of 1 milli second. Event log
includes trip circuit supervision 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 also in case the relay tem-
porarily loses its auxiliary supply.
The event log facilitates detailed post-fault analysis
of feeder faults and disturbances. The SoE informa-
tion can be accessed locally via the user interface
on the relay front panel or remotely via the commu-
nication interface of the relay.
9. Recorded data
The relay stores fault records of analog values for
two trip events in non-volatile memory. The fault
recording is triggered by the trip signal of protection
function. A sample of analog value is recorded for
every power frequency cycle. Fifteen such samples
are recorded, five before the trip and ten after the
trip event. These records enable the user to analyze
the two most recent power system events. Each
record includes the current values for three phases
and earth current.
The relay records the number of phase and earth
fault trip events into dedicated trip counters. These
trip counters can not be reset by the user and are
stored in non-volatile memory.
The recorded information can be accessed locally
via user interface on the relay front panel and can
be uploaded for subsequent fault analysis.
10. Self-supervision and test function
The relay’s built-in self-supervision system con-
tinuously monitors the state of the relay hardware
and the operation of the relay software. Any fault
or malfunction detected will be used for alerting
the operator. A permanent relay fault will block the
protection functions of the relay to prevent incorrect
relay operation.
The relay supports a built-in test mode which ena-
bles user to test the relay HMI and trip outputs.
Summary of Contents for REF601
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