Handling Of Acbs; Earthing Of Transformer/Generator Connection; Central Manual Bypass - ABB MNS-Up Service Manual

M N S 3 . 0 S E C T I O N S
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MNS 3.0 sections
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..
Transformer
Main Incomer
Input line
AC AC
DC DC
DC DC
AC AC
Output line
Main Distribu�on
Feeder
Distribu�on Feeders
(protected)
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.
Generator
Ba�ery
Gen Incomer
Ba�ery line
AC AC AC
DC DC DC
DC DC DC
AC AC AC
GS
Central
manual
Bypass
Distribu�on Feeders
(Non UPS proteced)
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