Monitoring And Self-Diagnosis; Protection - ABB REF 542plus Technical Reference Manual

1MRS755859
4.2.4.
4.3.
Multifunction Protection and Switchbay Control
Unit
Technical Reference Manual

Monitoring and self-diagnosis

The REF 542plus offers several features for monitoring the primary part as well for
self-diagnosis. The following computed quantities are available for primary part
monitoring:
Maximum and mean currents in the observation period (0 ... 30 min)
*
Sum of interrupted currents
*
Working hours
*
Number of switching cycles (open-close circuit breaker)
*
Spring charging time supervision (when applicable)
*
Opening coil supervision
*
The REF 542plus is equipped with self-diagnosis routines that constantly check the
hardware and software modules status. Every REF 542plus binary input and output
module is equipped with a watchdog contact that triggers in case of fault or power
loss. This contact can be used to detect unit failure and to initiate the appropriate
actions. Analog input channels can be optionally supervised. A broken wire in the
connection with an instrument transformer or a sensor can be detected and an alarm
can be activated.

Protection

REF 542plus offers a wide range of functions for protection. As previously
mentioned, a wide range of protection schemes for the protection of several system
components can be configured. The available protection functions can be combined
together to form the required protection scheme.
Current protection
Inrush blocking (68)
*
Overcurrent instantaneous (50)
*
Overcurrent definite time, 2 thresholds (51)
*
Overcurrent directional, 2 thresholds (67)
*
Overcurrent IDMT (51 IDMT)
*
Earth fault, 2 thresholds (51N)
*
Earth fault IDMT (51 IDMT)
*
Earth-fault directional, 2 thresholds (67N)
*
Earth-fault directional sensitive (67S)
*
Earth-fault directional sector (67NS), 10 thresholds.
*
Voltage protection
Overvoltage instantaneous (59)
*
Overvoltage definite time, 2 thresholds (59)
*
Undervoltage Instantaneous (27)
*
Undervoltage definite time, 2 thresholds (27)
*
Residual overvoltage, 2 thresholds (59N)
*
REF 542plus REF 542plus
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