Parallel System; Dual-Bus System - Huawei UPS5000-E Series User Manual

UPS5000-E-(50 kVA-300 kVA)
User Manual (50 kVA Power Modules)

2.4.2 Parallel System

In a parallel system, the mains input, bypass input, and AC output terminals between cabinets
are connected in parallel. Energy control modules (ECMs) on each UPS are connected over
parallel cables. The parallel connections synchronize the UPS outputs to supply power to
loads. If one UPS fails, the other UPSs continue supplying power to loads.
Figure 2-29 Conceptual diagram of an N+X parallel system

2.4.3 Dual-Bus System

A dual-bus system consists of two independent UPS systems. Each of these UPS systems in
turn consists of one or more UPSs connected in parallel. Of the two UPS systems, one is a
master system, and the other is a slave system. This design makes the dual-bus system highly
reliable and suitable for loads with multiple input terminals. An optional static transfer switch
(STS) can be installed to start the bus synchronization controller (BSC). The UPS systems
work in normal mode or bypass mode.
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