Parallel Operation - Eaton E DX Series User Manual

2. Installation

2.4 Parallel operation

1. Brief introduction of the redundancy
N+X is currently the most reliable power supply structure. N represents the minimum
UPS number that the total load needs; X represents the redundant UPS number, i.e.
the fault UPS number that the system can handle simultaneously. The bigger the X is,
the higher reliability of the power system is. For occasions where reliability is highly
depended on, N+X is the optimal mode.
As long as the UPS is equipped with parallel cables, up to 3 UPSs can be connected in
parallel to realise output power sharing and power redundancy.
2. Parallel installation
1) Users need to opt a standard 25-pin communication cable, which should have 25
cores, corresponding stitches and shield, as the UPS parallel cable. The length of the
parallel cable is appropriate to be less than 3 m.
2) Strictly follow the stand-alone wiring requirement to perform the input wiring of each
UPS.
3) Connect the output wires of each UPS to an output breaker panel.
4) Disconnect the Jumper JP1 and JP2 of the terminal block first, and connect each
output breaker to a main output breaker and then to the loads.
*The requirement of the output wiring is as follows:
l
When the distance between the UPSs in parallel and the breaker panel is less than 20
meters, the difference between the wires of input & output of the UPSs is required to
be less than 20%;
l
When the distance between the UPSs in parallel and the breaker panel is more than
20 meters, the difference between the wires of input & output of the UPSs is required
to be less than 10%.
3. Operation and maintenance
1) To perform the general operation, follow the stand-alone operating requirement;
2) Startup: The units transfer to INV mode simultaneously when they start up sequentially
in utility power mode;
Shutdown: the units shut down sequentially
in INV mode. When the last one completes
the shutdown action, each unit will shut down
the inverter simultaneously and transfer to
bypass mode.
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