861-9601.9 • INSTALLATION AND OPERATING INSTRUCTIONS • 8DA10 • Revision 11
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Installation
22
Installation work with SF
6
gas before commissioning
If a rated short-duration power-frequency withstand voltage test has to be carried out on site,
the work with insulating sulfur hexafluoride gas (SF
6
) described in this section must be
performed in advance.
22.1
Completing busbar assembly and filling with SF
6
gas
The individual phases and sections of the busbar (called
busbar runs
hereafter) must be filled
with SF
6
gas on site. Each busbar run forms one gas compartment.
Busbar runs within one transport unit that are already filled and closed hermetically at the
factory
are not filled with SF
6
gas on site.
All parts of the switchgear that have to be filled with gas are equipped with desiccant bags in
order to eliminate residual humidity in the gas filling. In ambient air, the desiccant agent loses
its effectiveness rapidly.
To expose the desiccant bags as briefly as possible to the ambient air, the following
installation and gas work is performed
completely on one busbar run
, and is then continued
on the next busbar run, etc.
For equipping of busbar housing covers with desiccant bags, see page 47, "Overview of
busbar housing covers with desiccant bags".
➭ Remove all covers with the
"Filter"
inscription from the busbar housings of one busbar run.
➭ Clean busbar housings that are dirty inside with a hand vacuum cleaner.
The hand vacuum cleaner must feature a plastic tip.
➭ Clean the bushing plates with a cloth.
WARNING
Danger of suffocation
Inhaling high concentrations of SF
6
can cause death or serious injury.
SF
6
gas is heavier than air. SF
6
gas concentrates first near to the floor and in floor openings.
➭ Observe the safety data sheet for SF
6
gas.
➭ Do not enter confined spaces where SF
6
gas may accumulate.
➭ Check and document reusability (dew-point, gas quality) before working with SF
6
gas.
➭ While working with SF
6
gas, provide for good ventilation.
➭ After working with SF
6
gas, vent the cable basement and any hollows in the floors with
special care.
WARNING
In the ambient air, the desiccant bags lose their effectiveness rapidly
The formation of condensation can lead to corrosion of switchgear parts. High air
humidity can lead to creepage distances.
➭ If a gas compartment has been open for more than 30 minutes, replace all desiccant bags.
➭ Do not open the packing of the desiccant bags until right before putting them into the
panel.
➭ Use only desiccant bags whose packing is not damaged and whose humidity indicators in
the packing are
blue
.
➭ If the humidity indicators are
pink
, do not use the desiccant bags.
➭ If the desiccant bags have been exposed to the air for more than 30 minutes, do not use
the desiccant bags anymore.
➭ After opening the packings, mount the desiccant bags in the gas compartment within
30 minutes.
➭ Close the gas compartment hermetically with sealing rings (O-rings).
➭ Evacuate the gas compartment immediately.