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861-9601.9 • INSTALLATION AND OPERATING INSTRUCTIONS • 8DA10 • Revision 11
35/214
Description
17.4
Insulating gas
The sealed pressure system of the switchgear contains the insulating gas SF
6
(fluorinated
greenhouse gas, GWP 22,800).
Example for a typical amount of SF
6
gas: 8DA10 circuit-breaker panel 36 kV, 40 kA, 1250 A,
cable connection 2 x plug size S3 with 2.8 kg SF
6
(CO
2
e = 64t).
The respective amount of SF
6
gas included is indicated on the rating plate of the switchgear.
Sulphur hexafluoride SF
6
according to IEC 60 376 is used as insulating gas. SF
6
insulates live
parts between each other and against earth potential.
When several switchgear sections have to be delivered, the switchgear is delivered ex works
partly with SF
6
filling ready for service. To fill all gas compartments completely with SF
6
,
SF
6
gas and a filling device must be provided on site. If the switchgear is delivered as one
switchgear section (possible for switchgear assemblies comprising up to 4 panels), the
switchgear is delivered ex works completely with SF
6
filling ready for service. The SF
6
filling is
provided to last the total service life of the switchgear.
Filling quantity as per rating plate.
Features
• Non-toxic
• Odorless
• Colorless
• Non-inflammable
• Chemically neutral
• Electronegative
• Heavier than air
Filling degree of
compressed gas cylinders
1.04 kg SF
6
/ liter cylinder volume (valid at a max. ambient air temperature of +65 °C).
Vapor pressure over
liquid SF
6
In the supplied cylinders, about 2/3 of the cylinder volume is liquid at +20 °C, the rest is
saturated SF
6
vapor.
Vapor pressure as a
function of temperature
Storage
Store the cylinders in vertical position in a cool place.
Gas pressures in kPa
at 20°C
All gas pressures specified are relative overpressures at an ambient air temperature of 20 °C,
and are valid for IEC, GOST and GB.
Temperature
Vapor pressure
+ 20 °C
2100 kPa
+ 30 °C
2700 kPa
+ 65 °C
7000 kPa (test pressure of cylinder)
INFORMATION
Select the gas pressure according to the higher value of the rated lightning impulse withstand
voltage or rated short-duration power-frequency withstand voltage.