Eaton Power Xpert 9395P, Руководство пользователя и инструкция по установке

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P-164000476
9395P 500kVA / 600 kVA 76
Revision 002 User’s and Installation Guide
6.4.3 Bypass mode – distributed bypass
In Bypass mode, the output of the system is provided with three-phase AC power directly from the
bypass input. While in this mode, the output of the system is not protected from fluctuations, spikes,
or power outages from the source. No battery support is available to the output of the system in the
Bypass mode of operation.
The distributed bypass system automatically switches to Bypass mode if it detects a UPS system
overload or load fault.
If one UPS becomes unavailable, the distributed bypass system dynamically updates the redundancy
calculation to determine if the remaining UPSs can support the load. If the load can be supported, the
system does not switch to bypass.
Figure 6-12 shows the path of electrical power through the parallel system when operating in Bypass
mode.
Figure 6-12. Path of current through the UPSs in bypass mode – distributed bypass
In a distributed bypass system, each UPS operates similar to a single UPS, but in parallel with the
others. The bypass source for the load is derived from the bypass input of one, two, three, or four
UPSs, depending on the system configuration, through the internal static switches. If a module is
taken offline, the other modules remain online to support the load. Load can be supported as long as
there is a sufficient number of modules, otherwise the load must be transferred to maintenance
bypass or shut down.
The distributed bypass system can be transferred from Normal mode to Bypass mode manually.
However, the distributed bypass system automatically switches to Bypass mode whenever the UPSs
can no longer supply the critical load. If the distributed bypass system transfers to Bypass mode from
Normal mode due to an output voltage deviation, the distributed bypass system automatically attempts
to return to Normal mode (up to three times within a 10-minute period). After three transfer attempts or
an overload, the system locks the critical load to the bypass source and requires operator intervention
to transfer.
Bypass mode is a normal operating mode, not an alarm condition. However, if the distributed bypass
system is unable to return to Normal mode following an automatic transfer to Bypass mode, an alarm
condition is recorded.
Bypass may also be used when the UPSs or UPMs in the system must be shut down to perform
routine maintenance or repairs.
Main Power Flow
Output to
Critical Load
UPS Input
Tie Cabinet
UPS 1 Output
(closed)
(closed)
(closed)
(closed)
Bypass Input
UPS 2 Output
UPS 3 Output
UPS 4 Output
De-energized
Battery
Battery
Battery
Battery
UPS 1
UPS 2
UPS 3
UPS 4