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Vertiv I Liebert ITA2 30kVA I Manual
3
Parallel UPS Installation And Commissioning
This chapter introduces the features, requirements, installation and commissioning of the
parallel system.
The UPS parallel system provides the user with N + X (2 ≤ N + X ≤ 4, X=0 or 1) parallel
configuration, N stands for the basic parallel sets, X stands for the redundant sets.
1 + 1 parallel POD (optional) can provide safe and reliable power distribution function for the
parallel system. The 1 + 1 parallel system only needs one 1 + 1 parallel POD; if N is not less
than two, the external self-distribution will be required for the parallel system.
3.1
Features
1. The software and the hardware of each UPS in parallel system are the same as those of the
single UPS. The basic parameters of the parallel system can be set through the LCD (Refer
to
3.5.2 Parallel System Parameters Setting
for details), and the detailed parameters can be
set through the background software (For service engineers only). For all UPSs of the parallel
system, the requirements of the parameter settings are same.
2. The parallel cables form a ring connection (Refer to
3.4.2 Connecting Parallel Cables
for
details) to provide reliability and redundancy for the system. The intelligent parallel logic
provides the user with maximum flexibility. For example, each UPS in the parallel system can
be switched off or on in random order; seamless transfer can be achieved between Normal
mode and Bypass mode, and the transfer is automatically recoverable: that is, after the
overload is removed, the system will return to the original operation mode automatically.
3. The total load of the parallel system can be queried through the LCD of each UPS.
3.2
Requirements
A UPS system composed of multiple parallel-connected UPSs is equivalent to a large UPS
system. Nevertheless, it provides increased system reliability. To ensure equal utilization of all
UPSs and compliance with relevant wiring regulations, the following requirements must be
met:
1. All single UPSs must have the same capacity. The UPS must be connected to the same
bypass source.
2. The bypass input power and the rectifier input power must be connected to the same
neutral line input terminal.
3. If a residual current detector (RCD) is required, it must be set correctly and installed before
the same neutral line input terminal, or it must monitor the protective earth current of the
system. Refer to
'Warning: high leakage current'
of Safety Precautions before Contents.
4. The outputs of all single UPSs must be connected to the same output bus.
