User Manual

3UG4624 residual current monitoring relay
8.3 Functions
3UG4 / 3RR2 monitoring relays
174 Manual, 02/2013, NEB927043002000/RS-AA/002
Monitoring
If the measured residual current exceeds the set warning threshold (I!), the associated CO
contact 21-22-24 changes the switching state without delay and a (!) appears on the display
as an indication. If the measured fault current exceeds the set threshold (I▲), the set delay
time (I▲Del) starts and the associated relay symbol flashes. After this time has expired, the
associated CO contact 11-12-14 changes the switching state.
On the display, the currently displayed measuring value and the symbol for overshoot flash.
Note
The neutral conductor must no longer be grounded after the summation current transformer
because otherwise the residual current monitoring function cannot be ensured.
Startup delay
To be able to start a drive, the output relay switches to the correct state during the ON-delay
time (onDel) depending on the selected open-circuit principle or closed-circuit principle, even
if the measured value is still under the set value.
Tripping delay
If the measured value overshoots or undershoots the set threshold after expiry of the ON-
delay time (onDel), the set tripping delay time (Del) and the relay symbol will flash. After
expiry of this time, the output relays change the switching state. On the display, the current
measuring value and the symbol for undershoot or overshoot flash.
Note
The 3UG4624 residual current monitoring relays are only suitable for line frequencies of 50 /
60 Hz!
You will find the switching states of the output relays below in section "Function diagrams"
and in Chapter "Diagnostics (Page 179)."
Tripping conditions
The combination of the 3UG4624 residual current monitoring relay with the 3UL22
summation current transformer responds according to the following tripping conditions:
Fault current monitoring relays Fault current
No tripping 0 to 50 % of the set threshold
Tripping not defined 50 to 100 % of the set threshold
Tripping >= 100 % of the set threshold