6.7.2 Functions
General functionality
The 3UG4617 line monitoring relays monitor a three-phase system for phase sequence, phase
failure, phase asymmetry, undervoltage, and overvoltage.
Note
The 3UG4618 line monitoring relays have the same functions as the 3UG4617 monitoring relays
and also monitor the neutral conductor for failure.
The devices feature a wide-range voltage input and are self-powered (measuring voltage
= rated control supply voltage) and work on the closed-circuit principle. Depending on the
version, the line monitoring relays are powered with a line-to-line voltage of 160 to 690 V
(3UG4617) and with a line-to-neutral voltage of 90 to 400 V (3UG4618) through terminals
L1 / L2 / L3.
The 3UG4617 / 3UG4618 line monitoring relays have a display and are parameterized with three
keys.
You will nd the setting ranges and factory settings of the available parameters in Chapter
"Operation (Page 116)."
You will nd a description of the individual parameters in Chapter "Parameters (Page 281)."
Note
The specied voltages represent the absolute thresholds.
Monitoring
Output relay K1 is for warning or shutdown on faults in the power system (voltage, asymmetry).
Output relay K2 responds dierently depending on the phase sequence.
Phase sequence
If the correct phase sequence is applied to terminals L1‑L2‑L3, output relay K2 (relay contact
21-22-24) picks up. This is represented by a relay symbol on the display. If the phase sequence
is incorrect, output relay K2 will not pick up. An error is not indicated on the display; only the relay
symbol remains in the disconnected state.
Undervoltage or overvoltage
If the monitored voltages (Ux-y) are larger than the set lower voltage value (U▼) and smaller
than the set upper voltage value (U▲), i.e. they are within the voltage limits and the line voltage
asymmetry (Asy) is less than the set value, the output relay K1 (relay contact 11‑12‑14) picks up
approx. 50 ms after the response of output relay K2 (relay contact 21‑22‑24).
3UG4.1 line monitoring relay
6.7 3UG4617 / 3UG4618 line monitoring relays
SIRIUS 3UG4 / 3RR2 monitoring relay
Equipment Manual, 07/2021, NEB927043002000/RS-AD/005 113
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