Eaton Powerware 9395, Инструкция по установке и эксплуатации

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UNDERSTANDING UPS OPERATION
Eaton 9395 UPS (450–825 kVA) Installation and Operation Manual
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164201725 Rev 4
www.eaton.com/powerquality 6-36
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In VMMS mode, the UPS operates as a traditional double-conversion UPS, but
selectively shifts the load to fewer UPMs to increase the efficiency of the UPS. In
a parallel system each UPS will require at least one UPM to be in double
conversion mode at all times; otherwise, VMMS mode operates the same as it
does in a single UPS system (see paragraph 6.2.4).
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In Bypass mode, the critical load is directly supported by utility power through the
bypass circuit in each UPS.
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In Battery mode, the battery provides DC power, which maintains UPM operation.
The UPM batteries support the critical load.
The UPSs continually monitor themselves and the incoming utility power and
automatically switch between these modes as required, without operator
intervention, except when manually switching to Bypass mode. The sophisticated
detection and switching logic inside the UPSs ensures that operating mode changes
are automatic and transparent to the critical load, while internal monitoring systems
indicate the current mode of operation. The UPSs switch operating modes in
response to these system events:
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A command is an intervention that is externally initiated by an operator or by some
site action. A command causes the UPSs to switch operating modes; it usually
does not require any further action.
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A notice is a minor system event that may or may not require attention.
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An alarm is a system event that requires immediate intervention.
The following paragraphs describe the differences in the parallel system operating
modes, using block diagrams to show the power flow during each mode of operation.
6.4.2 Online Mode – Distributed Bypass
In Online mode, utility AC power is supplied to the UPSs. Each UPS then conditions
the incoming AC power and provides clean, regulated AC power to the tie cabinet or
distribution panel for parallel systems up to four modules. The applied load is shared
equally among the available UPMs in the system.
Figure 6‐30 shows the path of electrical power through the parallel system when
operating in Online
mode.
If the utility AC power is interrupted or is out of specification, the UPSs automatically
switch to Battery mode to support the critical load without interruption. When utility
power returns, the UPSs return to Online mode.
If the UPSs become overloaded or unavailable, the distributed bypass system
switches to Bypass mode. The distributed bypass system automatically returns to
Online mode when the overload condition is cleared and system operation is restored
within specified limits.