abb
SafeLink
SF
6
Insulated Ring Main Unit
Installation and Operating Instructions
SLMIO ver 2.12
ABB Ltd, Switchgear Division, Auckland, New Zealand
12
3 Maintenance
3.1 Environmental
The SafeLink switching enclosure is a gas-tight welded stainless steel compartment able
to withstand a harsh environment. However, it is important that the base of the SafeLink
installation be kept free of vegetation or other material to prevent corrosion of the stand
and/or enclosure.
3.2 Maintenance
All components within the SF
6
insulated tank are maintenance free for the life
expectancy of the unit. The tank is made of stainless steel.
Scratches or other damage to panels must be repaired.
Mechanical parts located outside the sealed tank are surface treated or made of
corrosion resistant materials. These parts are lubricated during manufacture for the
unit’s life expectancy.
Units installed in extreme conditions are likely to require inspection depending on the
nature of the environment.
Where an outdoor enclosure is used, this should be checked periodically for scratches or
corrosion and the base of the stand must be kept clear of vegetation and well ventilated.
3.3 Gas Sampling and Filling
The gas density gauge on the front of the SafeLink shows the density of SF
6
gas in the
unit. All units are tested to ensure that any leakage rate is so low as to give a thirty-year
service life. During switching, the arc formed will cause the gas to dissociate. Once the
arc is extinguished the SF
6
reforms. A molecular sieve is fitted inside the switching
enclosure to absorb any remaining ion products.
When samples are required these are taken through the
Dilo
fitting of the gas density
gauge on the front of the unit in the fuse compartment. Therefore, the fused switch must
be switched to the
earth
position and the selector placed in the blocked position. The
sample must be taken with the sampling kit available from ABB. This will ensure that
any gas escaping during the sampling process is minimised.
Gas is added through the same connection used to take samples. The ABB filling
adaptor allows the pressure inside the switch to be monitored during filling. Full details
are included with the filling adaptor.