Self-Supervision - ABB REU 523 Technical Reference Manual

REU 523
4.1.1.9.
4.1.2.
12
Combined Overvoltage and Undervoltage Relay
Technical Reference Manual

Self-supervision

The self-supervision system of the REU 523 manages run-time fault situations and
informs the user about an existing fault. When the self-supervision system detects a
permanent internal relay fault, the READY indicator LED will start to blink. At the
same time the self-supervision alarm relay (also referred to as the IRF relay), which
is normally picked up, will drop off and a fault code will appear on the LCD. The
fault code is numerical and identifies the fault type. For fault codes, refer to section
Internal fault in the Operator's Manual.
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Fault codes can indicate:
• no response on the output contact test
• faulty program, work or parameter memory
• too high or too low a reference voltage value
Measurements
The table below presents the measured values which can be accessed through the
HMI, expressed as multiples of the rated voltage, U
Table 4.1.2-1 Measured values
Indicator Measured data
U Main voltage U
12
U Main voltage U
23
U Main voltage U
31
U Positive-phase-sequence voltage
1s
U Maximum voltage of the three main voltages
max
U Minimum voltage of the three main voltages
min
U Average voltage of the three main voltages during one minute
1min
U Average voltage of the three main voltages during ten minutes
10min
12
23
31
1MRS 750942-MUM
, of the energizing input.
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