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.

 

 

Gas density monitor

Unique SF6 monitoring with reference gas comparison

The Gas Density Monitor functions on the principle of reference gas comparison and therefore does not require
temperature compensation.

It is much more accurate than bimetal compensated pressure  gauges and it is extremely vibration and shock resistant. Since no recalibration of switch points is needed, it operates maintenance-free.

Since no recalibration of switchpoints is needed, it operates maintenance-free. The operating temperature ranges are from –60 °C up to +80 °C.

Gas density sensor

Electronic SF6 gas density monitoring with patented quartz tuning fork

The Gas Density Sensor uses a quarz tuning fork to sense gas density directly – a unique technology patented by Trafag. With the delivery of continuous output signals (analogue or digital) from this electronically operating sensor, Trafag opens new paths for the energy distribution industry.
Utilizing the analogue or digital signal, comprehensive SF6 gas monitoring or SF6 gas trend analysis of switchgear components is implemented easily.

Hybrid SF6 Gas Density Monitor

Unique SF6 monitoring: Combined mechanical AND electronic monitoring

The Hybrid Gas Density Monitor combines the advantages of both the mechanical gas density monitorand the electronic gas density sensor in a compact all-in-one apparatus: With its analogue or digital output it is the ideal gas density monitor for smart online SF6 gas management systems. It also has a local gas pressure indication and alarm contacts.