What is SF6?
Sulphur hexafluoride (SF6) is used in gas insulated switchgear because of its remarkable 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 property. 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 Monitoring Devices
Trafag’s product range of gas density measuring devices splits into three different product groups: The mechanically working Gas Density Monitor, the electronic Gas Density Sensor and the Hybrid Gas Density Monitor, monitoring both mechanically and electronically. Listed below are more detailed information on them.
Gas Density Monitor
Unique SF6 monitoring with reference gas comparison
Trafag Gas Dennsity Monitor functions on the principle of reference gas comparison and therefore no temperature compensation is necessary. It works electromechanically and is thus independent of electrical energy supply. Since no recalibration of switchpoints is needed, it operates maintenance-free. The operating temperature ranges are from –60 °C up to +80 °C.
Trafag Gas Density Sensor
Electronic SF6 gas density monitoring with patented quartz tuning fork
The Gas Density Sensor uses a quartz tuning fork to sense gas density directly – a unique technology patented by Trafag. With the delivery of continuous output signals (analog or digital) from this electronically operating sensor, Trafag opens new paths for the energy distribution industry. Comprehensive SF6 gas monitoring or SF6 gas trend analysis of switchgear components is implemented easily.
Hybrid Gas Density Monitor
Unique SF6 monitoring: Combined mechanical and electronic monitoring
Trafag Hybrid Gas Density Monitor combines the advantages of both the mechnical gas density monitor and the electronic gas density sensor in a compact all-in-one apparatus: With its analogue output it is the ideal gas density monitor for SF6 gas management trending systems but it also has a local gas pressure indication and alarm contacts.