1
1MRS 751123-MBG
Issued: 15.06.1999
Status: Updated
Version: B/23.11.2001
Data subject to change without notice
REU 523
Combined overvoltage and undervoltage
relay
Features
• Over and undervoltage protection
• Single- or three-phase use
• High-set overvoltage stage with definite-
time or inverse definite minimum time
(IDMT) characteristic
• Low-set overvoltage stage with definite-
time or IDMT characteristic
• High-set undervoltage stage with definite-
time or IDMT characteristic
• Low-set undervoltage stage with definite-
time or IDMT characteristic
• Positive-phase-sequence protection
• Adjustable drop-off/pick-up ratio for the
low-set stages
• Circuit-breaker failure protection (CBFP)
• Disturbance recording up to 12 seconds
-
triggering by a start or a trip signal from
any protection stage and/or by a binary
input signal
-
records three analogue channels and
eight digital channels
-
adjustable sampling rate
• Non-volatile memory for
-
up to 60 event codes
-
setting values
-
disturbance recorder data
-
recorded data of the five last events with
time stamp
-
number of starts for each stage
- alarm indication messages and LEDs
showing the status at the moment of
power failure
• Three accurate voltage inputs
• Galvanically isolated binary input with a
wide input voltage range
• All settings can be modified with a personal
computer
• HMI with an alphanumeric LCD and
manoeuvring buttons
• IEC 60870-5-103 and SPA bus communi-
cation protocols
• Two normally open power output contacts
• Two change-over signal output contacts
• Output contact functions freely configura-
ble for desired operation
• Optical PC-connector for two-way data
communication (front)
• RS-485 connector (rear) for system com-
munication
• Continuous self-supervision of electronics
and software. At an internal relay fault, all
stages and outputs are blocked
• User-selectable rated frequency 50/60 Hz
• User-selectable nominal voltage 100/110/
115/120 V
• User-selectable password protection for
the HMI
• Display of primary voltage values
• Demand values
• Multi-language support
