Swiss-based Trafag stands for precise, reliable and maintenance-free instruments developed for the monitoring of SF6 and other gases in the field of high- and medium-voltage switchgear. Trafag guarantees outstanding accuracy and operation in the widest temperature range on the market. Trafag gas monitoring devices measure the gas density directly, i.e. SF6 Gas Density Monitors, with the unique gas density reference principle or the patented quartz tuning fork technology, i.e. SF6 Gas Density Sensors, or by combining both principles, i.e. SF6 Hybrid Gas Density Monitors. They thus offer the most reliable solution on the market by directly measuring the SF6 gas density.

Trafag’s product range of gas density measuring devices splits into three different product groups:

  • The mechanically acting SF6 Gas Density Monitors (87x6, 87x7, 87x8)
  • The electronic SF6 Gas Density Sensors (8774; 8775)
  • The SF6 Hybrid Gas Density Monitors (878x, 879x)

Superior SF6 gas density monitoring for maximum safety

Sulphur hexafluoride (SF6) is used in gas insulated switchgear because of its outstanding insulation and spark extinguishing (arc-quenching) properties. It thus makes it possible to set-up complex and safe ­power distribution systems even in large cities. The insulation strength depends basically on the gas density.
The safety of the facility is guaranteed when the correct level of gas density is maintained within the enclosed systems. The tightness of the installation has to be checked and controlled constantly as a leakage would result in a decrease in the insulation properties. Because SF6 is a strong greenhouse gas, strict regulations regarding the SF6 consumption have to be met by the switchgear operators in an increasing number of countries. These regulations stipulate a permanent monitoring of gas leakage which is done with gas density monitors or gas sensors. Gas density is often indirectly determined by the gas pressure using manometers or pressure sensors. As the pressure in the hermetically closed volume varies enormously with temperature, such devices need temperature compensation, which are a source of errors.