ABB REF 542plus - Page 6

Feeder Terminal REF 542plus
1MRS756269
6
Application Monitoring and self-diagnosis
The REF 542plus offers several features for
monitoring the primary part as well as self-
diagnosis. The following computed quantities
are available for primary part monitoring:
• maximum and mean currents in the obser-
vation period (0 ... 30 min)
• sum of interrupted currents
• operating time
• number of switching cycles (open-close
circuit breaker)
• spring charging time supervision (when
applicable)
• trip coil supervision
The REF 542plus is equipped with self-diag-
nosis routines that constantly check the hard-
ware and software modules status. Every
REF 542plus binary input and output module
is equipped with a watchdog contact that trig-
gers in case of fault or power loss. This con-
tact can be used to detect unit failure and to
initiate the appropriate actions. Analog input
channels can be optionally supervised. A bro-
ken 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 pro-
tection of several system components can be
configured. The available protection func-
tions depend on the ordered software
licenses. The licenses are Basic Low, Basic,
Multi Low, Multi, Differential and Distance.
In table 20 the corresponding provided pro-
tection functions are listed.
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)
Line protection:
• distance protection (21)
Differential protection:
• differential protection for motors and
transformer (87)
• restricted earth-fault for transformer
(87N)
Thermal protection:
• for cables, motors and transformers (49)
Motor-specific protection:
• number of starts counting (66)
• locked rotor (51LR)
• motor start (51MS)
• low load (37)
• unbalanced load (46)
Power quality mitigation:
• power factor controller (55)
• switching resonance protection
• high harmonics protection
Other protections and related functions:
• frequency protection (81), 6 thresholds
per net
• synchro check (25)
• fault recorder
• autoreclosure (79)
• directional power (32).
At most 24 protection functions can be
installed inside the REF 542plus unit. The
maximum number is anyway dependent upon
the available processing power.