Salicru SLC CUBE 3+ PS Mode D'emploi page 111

R-S-T
N
R-S-T
N
Fig. 29. Single line diagram, connection of parallel system up to 4
SLC CUBE3+ PS B equipments.
4.5. OPERATING STRUCTURE OF A
PARALLEL SYSTEM.
The Uninterruptible Power Supply Systems SLC CUBE3+ PS se-
ries, are designed and thought for its «parallel» connection with a
maximum of four units, on condition that they are the same model
(setting, voltage, power, frequency, back up time, ...), all of them
without adding hardware. Fig. 27 and 28, as an example, show the
circuit diagrams of a three phase/three phase parallel system, with
and without separate static bypass line. Both circuit diagrams are
only showing the input-output power connections and the parallel
control BUS.
A part from the possible setting, conceptually, the parallel systems
are divided in two similar structures and at the same time very dif-
ferent depending on the application.
Systems connected in parallel or active parallel, supply the loads
equally among them. Less when there is only one UPS, the system
will be able to be redundant or non-redundant depending on the
needs and requirements of the application.
Simple parallel system (non-redundant): a non-redundant
•
parallel system, is that one where all UPSs supply the required
power by the loads. Total power of the system based on N
equipments of nominal power rate Pn, is N x Pn.
If the system is operating with a load close or equal to the max-
imum and one of them faults, the load will be shifted to bypass
automatically with make before break technique, because it
will not be able to support the consumption demand due to the
overload that it will be caused in the rest of UPSs.
USER'S MANUAL
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Redundant system: a redundant system is that one has one
•
or more UPSs than the minimum required by the total power of
the system (depending on the redundancy level), being the load
fair shared among them. So, the fault of any of them will cause
that the damaged UPS will be out of the system and the rest
will continue supplying the load with all the guarantees. Once
the damaged UPS is fixed, it can be connected to the system in
order to recover the redundant condition.
A system with his configuration increases the reliability and
assures an AC power supply of quality for the most critical
loads.
The quantity of redundant equipments to be connected has to
be studied according to the requirements of the application.
Parallel connection, redundant or not, adds several advantages
a part from the connection itself:
Higher punctual power and back up time: in a parallel
•
system of N+M equipments, it is considered the nominal max-
imum load of N equipments and +M are the reserve ones, so:
N, is the quantity of equipments in parallel, corresponding
ˆ
to the minimum quantity required by the total needed
power.
+M, is the additional quantity of equipments corresponding
ˆ
to the residual safety power (redundant equipments).
SLC CUBE3+ PS UNINTERRUMPTIBLE POWER SOURCE
U-V-W
N
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