Vertiv Liebert EXS 80kVA UPS, Руководство пользователя

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Vertiv™ Liebert EXS 80kVA UPS User Manual
6 Parallel System and LBS System
6 Parallel System and LBS System
This chapter gives details on the installation of parallel system and LBS system.
6.1 General
The UPS parallel system consists of up to four single UPS of the same model. The parallel system does not
require a centralized bypass. Instead the bypass of each UPS shares the load when the system transfers to
the mains bypass supply.
From a ‘power’ viewpoint, each module is internally identical to the ‘single module’ configuration. A parallel
system requires inter-module control signals to manage the load sharing, synchronizing and bypass
switching. The control signals are connected through the parallel cables, which are multi-way ribbon cables
connected between the units of the system to form a ring.
When two or more modules are to be connected in parallel, it is recommended that inductor should be
inserted in the bypass line. This can be installed internal to the UPS as an option.
6.2 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.
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.
6.3 System Installation Procedures
The basic installation procedure of a parallel system comprising two or more UPS modules is the same
as that of single module system. This section only introduces the installation procedures specific to the
parallel system. The installation of a parallel UPS should follow the installation procedure for a single UPS
module with the additional requirements detailed in this section.
WARNING! To achieve normal operation of the parallel system, Vertiv service personnel must
execute the CAN resistance operation. Failure to do so could result in system fault.