Line protection
*
Distance (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
*
THD protection
Other protections and related functions
*
Frequency protection (81), 6 thresholds per net
*
Synchro check (25)
*
Fault recorder
*
Autoreclosure (79)
*
Lock-out (86)
*
Reverse 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.
4.4.
Control
The control and automation capabilities inside the REF 542plus are extremely
powerful. Simple interlocking against switching errors as well complex load-
shedding schemes can be easily implemented with the control possibilities offered
by the REF 542plus.
22
REF 542plus
REF 542plus
Multifunction Protection and Switchbay Control
Unit
Technical Reference Manual
1MRS755859