ABB MNS-Up, Service Manual

Page: 63 / 84

63 M N S 3 .0 SEC T I O N S
—
MNS 3.0 sections
12
12.1 Handling of ACBs
For operating and maintenance on ACBs, check the respective service manuals.
12.2 Earthing of transformer/generator connection
A complete system shut off is required in case of:
• Extension of the system by adding additional sections
• Replacement of the EMC boards on the incoming or outgoing distribution bar
• Maintenance on the main busbar section
• Maintenance on the distribution bar
• Maintenance on the incoming and/or outgoing feeder connection bars
• Maintenance on the central manual bypass breaker connection bars
For save maintenance on the MNS-Up system, suitable earthing means must be provided in all ACB sections,
as shown below..
GS
AC
AC
DC
DC
Central
manual
Bypass
Distribu�on Feeders
( protected )
Distribu�on Feeders
( Non UPS proteced )
Output li ne
Input line
Gen Incomer
Generator
Main Incomer
Transformer
Ba�ery line
Ba�ery
Main Distribu�on
Feeder
AC
AC
DC
DC
AC
AC
DC
DC
AC
AC
DC
DC
AC
AC
DC
DC
Figure 12-01 Earthing means for safe maintenance
In case of maintenance on the MNS-Up modules a system shutoff is not required.
12.3 Central manual bypass
The central manual bypass is used to bypass the UPS system in case maintenance on the MNS-Up UPS modules is required.
The central maintenance bypass can be closed even if the MNS-Up UPS modules are switched on.
For save operation of the MNS-Up system using central maintenance bypass breaker, refer to concept power DPA500 manual
section 6.2.7.