Chapter 7 Parallel System & Dual Bus System 71
NX UPS Single Module And Parallel System 250kVA ~ 800kVA User Manual
Note
250kVA ~ 400kVA: Q1 is an optional configuration while Q2, Q3 and Q5 are standard configurations
500kVA 600kVA E: Q1, Q2, Q3 and Q5 are optional configurations
600kVA 800kVA:
:
~
~
Q3 is an optional configuration while Q1, Q2 and Q5 are standard configurations
UPS 1
Q1
Rectifier
Charger
Inverter
Static
switch
BCB
Battery 1
Q5
L1,L2,L3,N
Q1EXT
Q2EXT
L1,L2,L3,N
Q5
BCB
Q2
Q3
UPS 2
Q1
Q2
Q3
External
bypass
switch
E
xte
rna
l m
ain
te
nan
ce
by
pa
ss
QBYP
QUPS
To load
Input distribution
Mains input
L1,L2,L3,N
Mains input
L1,L2,L3,N
Rectifier
Charger
Inverter
Static
switch
Battery 2
Output distribution
Figure 7-1 Schematic of typical parallel system (with common input, separate batteries and output/bypass distribution cabinet)
7.2.3 External Protective Device
Refer to
3.1.7 External Protective Device.
7.2.4 Power Cable
The power cable wiring is similar to that of UPS module. The bypass and main input supplies must use the same
neutral line input terminal. If the input has a current leakage protective device, the current leakage protective device
must be fitted upstream of the common neutral sinking point.
Note
1. The power cables (including the bypass input cables and UPS output cables) of each UPS module should be of the same
length and specifications to facilitate load sharing.
2. The UPS may be in common input configuration or split bypass configuration. If the rectifier input and bypass input are fed from
two different power transformers, then these two power transformers must use the same grounding grid.
7.2.5 Parallel Cable
Shielded and double-insulated parallel cables available in lengths 5m, 10m and 15m must be interconnected in a ring
configuration between the UPS modules, as shown in Figure 7-2. The parallel ports J26 and J28 are provided on the
front panel of the control module in the bypass cabinet, as shown in Figure 7-3 and Figure 7-4. The ring connection
ensures the reliability of the control of the parallel system. Be sure to verify the reliable cable connection before
starting up the system!