System Bypass; Independent Mode - ABB HiPerGuard MV UPS User Manual

78 H I P E R G U A R D M V U P S U S E R M A N U A L
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8.3 System Bypass

The system can be bypassed from the GDM, digital I/O or Modbus TCP.
If the System Stop button is pushed on the GDM and the MV UPS is in Independent mode or the utility voltage is
not within acceptable limits, the system will ask the operator to confirm or abort the request. In case of confirma-
tion, the MV UPS will close the bypass and open Sout and Sin for each MV UPS block.
For single machine commands (HMI, Digital IO or Modbus), the single machine logic will apply, but the bypass will
only be opened when insufficient MV UPS blocks are online to support the load (parameter configured).
Step User Action
1 Press "Stop"
2
3
4
5
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Table 8.03: MV UPS
system stopping steps.
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8.4 Independent mode

The MV UPS transfers from the power conditioning mode to Independent mode during deep sag events and out-
ages according to the input breaker management curve.
Step User Action
No user action required; the system will operate fully
1
autonomously during this event.
2
3
4
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Table 8.04: MV
UPS transferring
automatically into
Independent Mode
System Response
If the MV UPS system is in Independent mode
or the utility voltage is not within acceptable
limits, the system will ask the operator to con-
firm to abort the discharge and initiate system
stop.
Commands to close Sabp while simultaneously
MV UPS (s) load voltage synchronize(s) with
utility voltage magnitude, frequency and
phase.
When Sabp is closed MV UPS(s) block(s) will
command to open Sout and then Sin
After Sout and Sin are opened, system will stop
PEBBs
System Response
System detects an event when utility voltage
drops below specified threshold level for a lim-
ited time which is based on Sin operation char-
acteristics curve.
The MV UPS opens Sin of each MV UPS.
The MV UPS regulates the load voltage with in-
ternal frequency and voltage as its references.