User Manual

3UG4.1 line monitoring relay
6.5 3UG4614 line monitoring relay
3UG4 / 3RR2 monitoring relays
118 Manual, 02/2013, NEB927043002000/RS-AA/002
6.5.2 Functions
General functionality
The 3UG4614 line monitoring relays monitor a three-phase system for phase asymmetry,
undervoltage, phase failure, and phase sequence.
The devices feature a wide-range voltage input and are self-powered (measuring voltage
= rated control supply voltage). The 3UG4614 line monitoring relays monitor all phases of
three-phase AC networks from 160 to 690 V through terminals L1 / L2 / L3 and also draw
power from all three phases simultaneously.
The 3UG4614 line monitoring relays feature 2 output relays (output relay K1 and output relay
K2). The relays work synchronously.
You will find the setting ranges and factory settings of the available parameters in Chapter
"Operation (Page 121)."
You will find a descri
ption of the individual parameters in Chapter "
Parameters (Page 351)."
Note
The specified voltages represent the absolute thresholds.
Monitoring
The output relays respond in accordance with the set relay switching behavior (closed-circuit
principle NC or open-circuit principle NO) if the following conditions are met:
● Correct phase sequence at terminals L1-L2-L3
● The monitored voltage (Ux-y) is larger than the set value
● The voltage symmetry (Asy) is smaller than the set value
If a fault occurs (phase failure, incorrect phase sequence, or phase asymmetry), the output
relays switch in accordance with the relay switching behavior.
In the case of incorrect direction of rotation, the 3UG4614 line monitoring relays immediately
shut down. Thanks to a special measuring method, a phase failure is detected with certainty
despite wide-range voltage from 160 to 690 V AC and reverse power of up to 80 % from the
load in the case of regenerative power recovery.
On failure of one of the phases, the output relays drop out immediately to protect the
application from any damage that may result. Set delay times have no effect on the phase
failure monitoring.
Note
The 3UG4614 line monitoring relays are only suitable for line frequencies of 50 / 60 Hz!