Resynchronize Mode; System Epo - ABB HiPerGuard MV UPS User Manual

80 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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8.5 Resynchronize mode

While the MV UPS(s) is (are) disconnected from the input and suppling the load, it monitors the input voltage for
the return of the grid supply or a backup generator. When the voltage reappears at the input, the MV UPS system
waits for 1-2 seconds to make sure that the supply is stable and reliable enough for reconnection. Then the resyn-
chronization to the input voltage starts automatically, as shown in the below steps.
Step User Action
No user action required; the system will operate fully
1
autonomously during this event.
2
3
4
5
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Table 8.05: MV UPS
resynchronize mode
and transfer to PCM
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8.6 System EPO

The system Emergency Power Off (EPO) is a digital input from site EPO signal that inhibits the MV UPS operation
in case of emergency shut down. The system will follow the below steps to shut down and eventually will fall into
bypass and isolated state.
Step User Action
1 Press "EPO"
2
3
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Table 8.06: MV
UPS Emergency
Power Off steps.
System Response
Utility voltage has recovered within nominal
range.
The MV UPS block resynchronizes the load volt-
age to the mains voltage magnitude, frequency
and phase.
When the Output voltage, frequency and phase
angle aligns with Utility voltage then MV UPS
closes Sin of all blocks simultaneously.
The MV UPS system is now in Power Condition-
ing Mode.
System Response
If the MV UPS unit is running, it will command
the Sabp breaker to close and Sin and Sout cir-
cuit breakers to open. If the unit is in bypass
mode, the MV UPS confirms that Sabp is closed
and Sin and Sout are opened.
Open all DC breakers at the DC energy source.