ABB HiPerGuard MV UPS User Manual page 54

54 H I P E R G U A R D M V U P S U S E R M A N U A L
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Figure 6.11: Parallel
machine communi-
cations network.
The Figure 6.11 shows n HiPerGuard MV UPS units connected in parallel. Note that two network switches are re-
quired (not included on MV UPS scope of supply), each with enough Ethernet ports to support the number of units
in parallel. The "redundant star" network topology is chosen to give a high level of integrity and enable operation
to continue in the event of a single network failure.
The control of the MV UPS units uses a peer-to-peer protocol, which eliminates the possibility of a single machine
failure bringing down the system, which is possible with a master-slave protocol. If any of the paralleled units de-
velops a fault and trips off, the others will seamlessly take over the load.
The two network switches will typically be powered from 24Vdc. It is recommended that they receive power from
separate no-break DC power supplies. This helps to improve the integrity of the system, enabling communica-
tions to continue, even after failure of the power to one of the switches.