Combined Over- And Undervoltage Release - ABB RELION REB500 Operation Manual

Section 7
Additional functions
Used as an undervoltage release criterion U< : The phase-to-earth voltages (U
measured. Used as an earth overvoltage release criterion 3U0>: Depending on the setting Uo
calculated internally, the neutral voltage is either evaluated and is derived internally from the
three phase voltages (
done in connection with the HMI500 configurator mode only.
Should a voltage be interrupted either due to a tripped MCB or an open-circuit, a voltage
function configured for overvoltage will disable, while one configured for undervoltage will
enable.
7.1.1

Combined over- and undervoltage release

The measurement of the undervoltage function is derived from the phase voltages (UL1, UL2,
UL3).
Depending on the setting Uo calculated internally, the measurement of the overvoltage
function is derived internally from the neutral voltage or is calculated from the phase voltages

( 3 U
0
the HMI500 configurator mode only. In the Detailed view, the voltage level can be set and the
function can be activated.
56

3 U U
0
An open VT circuit connected to an undervoltage function can be detected by
monitoring the signal 28805_Voltage criterion.
 
U U U ) or is fed externally (3U
L 1 L 2 L 3
In a combination of over- and undervoltage function (within a bay unit or in the
complete system), the overvoltage function has an effect on the neutral system
of the busbar protection (SSS_I0) and the undervoltage function of the
remaining functions (see the release matrix in
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 
U U ) or is fed externally (3U
L 1 L 2 L 3
). This setting can be done in connection with
0
1MRK 505 400-UEN B
, U , U
L1 L2
). This setting can be
0
GUID-7E96FB60-CD79-406A-9AA5-98EFCFBF64B4 v2
Section 7.1.2.2).
Distributed busbar protection REB500
Technical manual
) are
L3