Parallel redundant & power system UPS 60…800kVA FXS – Operating manual
Sistema parallelo ridondante e di potenza UPS 60…800kVA FXS – Manuale operativo
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JUD413937
Rev.A JSE414215 07/06/11
8.
POWER PARALLEL SYSTEM
8.1
DESCRIPTION POWER PARALLEL SYSTEM
The power parallel system is constituted by “N” UPS (up to a maximum of 5+1 units),
configurated as redundant parallel units. In the UPS 400-500-600-800 The Manual
Bypass is external and optional, and generally is only one for all units.
In addition to the standard functions as uninterruptible power supply, total power
control and protection of the load from mains distortion, the power parallel system
guarantees an uninterrupted power supply only in case of any internal failure in one of
the UPS units.
All units are constantly in operation and feed the load in parallel at “total load * n”,
where “n” is the number of the UPS.
The AC automatic current sharing control equalizes the currents of the “n” units and
reduces the total unbalance at less than 10%, under all load conditions.
The load is supplied by the inverters in parallel for an instantaneous overload up to “n
x 200%” of the nominal load of the single unit.
In case of a failure in one unit, the static bypass supply the load.
8.2
OPERATIONAL STATUS POWER PARALLEL SYSTEM
If a breakdown occurs for which a UPS can no longer distribute on the load, during
the state of “n UPS in normal functioning”, the power parallel system gets transferred to
the bypass all the units. The irregularies are registered by each UPS with alarms and
visualized on the same front panel of the UPS.
In the event that a system mode has a rectifier breakdown or mains loss, in the “n
UPS in normal functioning”, the UPS will continue to distribute the load discharging the
battery, automatically isolating itself from the system until the end of the back-up time
and transfers all the system in electronics bypass.
If the system is transferred to the Manual Bypass (MB), the load gets fed directly
from the mains, therefore not guaranteeing the continuity of the load and the entire
parallel system becomes separated from the load.
