Gas-filled medium voltage switchgear - avoids excessive pressure increases by setting internal gas pressure to normal air pressure at normal temp.

摘要

The MV switchgear is designed so that even with no pressure equalising device no excessively large pressures result inside the casing. The pressure of the insulating gas (e.g SF6) inside the switchgear's casing is chosen to lie between 3.945 and 1.03 bar absolute at roughly 20 deg.C. This means that at the max. ambient design temp. of 40 deg.C the pressure inside the casing is roughly 1.1 bar absolute. The preferred pressure inside the casing is 1.013 bar absolute at 20 deg.C, i.e normal air pressure.