Maintenance
of SF6 Gas
Sulphur hexafluoride (SF6) gas is an arc quenching and cooling
medium used in medium and high voltage electrical equipment as
an electrical insulator. Under the Kyoto Protocol, SF6 has been
classified as a greenhouse gas and restrictions are in place
to limit the amount allowed to be released into the atmosphere.
Both manufacturers and the users of their equipment are responsible
for the reduction in SF6 gas emissions. Organisations such as
the International Electrochemical Commission (IEC) and the International
Council on Large Electric Systems (CIGRE) provide guidance and
regulatory information with regards to the handling of such a
gas when it comes to maintenance.
When partial arcing or a failure occurs within electrical equipment,
this can cause the creation of decomposition products such as
sulphur dioxide and hydrogen fluoride. Analysis of SF6 gas is
recommended as part of a regular condition maintenance schedule,
this ensures that equipment and personnel are properly protected.
Early identification of elevated decomposition products will
help to eliminate power outages and failures, alongside unnecessary
inspections.
In order to ensure that no emissions occur throughout the testing
process, Cambridge Sensotec designed the Rapidox SF6 6100 Pump
Back gas analyser. The instrument draws a sample of SF6 gas from
the electrical equipment and analyses it in accordance with current
IEC and CIGRE test configurations. It then pumps it back either
automatically or manually, into the electrical equipment at pressure.
Alternatively, the analyser can store the gas internally for
proper disposal at a later time.
April 2016
