Functions - Siemens 3UG4 User Manual

3UG458. insulation monitoring relay
9.4 3UG4582/3UG4583 insulation monitoring relays
9.4.2

Functions

General functionality
The 3UG4582/3UG4583 insulation monitoring relays are supplied with a rated control and
supply voltage of 24 V to 240 V AC/DC, and they monitor the insulation resistance in
accordance with IEC 61557-8 in ungrounded IT-AC systems, IT-AC systems with
galvanically connected DC circuits, or IT-DC systems.
The devices can monitor control circuits (1-phase) and main circuits (3-phase). For this
purpose, the insulation resistance between the system cables (terminal L+ and L-) and
system ground (terminal
U = 0 to 250 V AC (15 to 400 Hz) / U
n
400 V AC (15 to 400 Hz) / U
measuring inputs, and their insulation resistance can be monitored.
The insulation monitoring relays have two rotary buttons (3UG4582)/four rotary buttons
(3UG4583) for adjusting the insulation resistance R and a Test/RESET button, to perform an
internal test on the device or to reset the device.
If the measured value drops below the set threshold, the output relays are set to fault status.
For systems with voltages over 400 V AC and 600 V DC, the 3UG4583 insulation monitoring
relays with 3UG4983 upstream module can be used for extending the voltage range.
You will find the setting ranges and factory settings of the available parameters in Chapter
"Operator control (Page 249)".
You will find a description of the individual parameters in the Chapter "Parameters
(Page 363)".
Measuring method
The 3UG4582/3UG4583 insulation monitoring relays use a new predictive measuring
method for high-speed measurements and fast pick-up times. The devices can be configured
to the relevant application conditions and are therefore versatile in use.
A pulsing measuring signal is fed into the system to be monitored and the insulation
resistance is calculated from this.
The received signal is different in form to the injected measuring signal. This change
depends on the insulation resistance and the system discharge capacity. The change to the
insulation resistance is predicted from this deviating form. If the predicted insulation
resistance corresponds to the insulation resistance calculated in the next measuring cycle
and is lower than the set threshold, output relay K1 responds depending on the device
configuration.
This adaptive measuring principle is suitable for detecting symmetrical insulation faults.
238
and KE) is measured. Systems with rated system voltages
= 0 to 300 V DC (3UG4582) or U
n
= 0 to 600 V DC (3UG4583) can be connected direct to the
n
= 0 to
n
3UG4 / 3RR2 monitoring relays
Manual, 05/2016, NEB927043002000/RS-AC/004