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Powerware BPIV Parallel Cabinet Installation and Operation
164201409 REV. B
101503
Understanding Parallel
System Operation
3.1
Looking Inside the Parallel System
The Parallel Cabinet extends the normal operation of the Powerware BPIV UPS
units by offering parallel capacity/redundant capability. The Parallel system
continues to maintain power to the critical loads during commercial electrical power
brownout, blackout, overvoltage, undervoltage, and out-of-tolerance frequency
conditions. Refer to Drawing 164201409---5 in Appendix A of this manual for the
detailed relationship of the Parallel Cabinet and the UPMs.
The output of the system is normally supplied by several Uninterruptible Power
Modules (UPMs). Multiple UPMs are connected with their outputs in parallel to
provide a load level greater than the rating of one UPM and/or for redundancy
.
The
paralleled UPMs supply the output load with protected power as long as the load
does not exceed the combined rating of the paralleled UPMs.
The power system is redundant as long as one of the UPMs can be disconnected
from the output bus and the remaining UPMs can continue to supply power to the
load without exceeding their ratings.
The Parallel Cabinet contains components that allow the the UPMs to be paralleled
and the source of system output power to be transferred between Bypass and the
paralleled UPMs
.
When the load is being supplied by the UPMs, the system output bus is
continuously monitored for an over or under voltage condition. If an out of limits
condition is detected, the Parallel Cabinet will transfer the load to bypass using the
UPM static switches and the bypass contactor in the Parallel Cabinet.
During manual transfers to bypass or maintenance, the critical load can be
supplied power through the bypass contactor in the Parallel Cabinet. The
upstream bypass input and breaker must be rated for the total system load since it
must supply all of the system load when on bypass.
Communication is required between the Parallel Cabinet and UPMs for full system
operation. System level communications and control are accomplished using a
CAN network. A single building alarm in each UPM, tied to the bypass contactor
auxiliary contacts in the Parallel Cabinet, will be used for a secondary
communication path.
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