SF6 insulates and extinguishes the arc in GIS and circuit breakers. If moisture or decomposition products build up in it, equipment life falls, and a leak lowers the pressure in the compartment.
Two tasks, two types of instrument
- Gas quality: a Rapidox analyser measures composition and moisture on the equipment itself.
- Tightness: an Ion Science leak detector finds where SF6 escapes.
For the detailed procedure see how to check SF6 quality at a substation. On moisture: SF6 moisture limits; on decomposition: SO2 and HF.
What to choose
A portable analyser suits field checks and a fixed system suits continuous monitoring of a room. The choice depends on the number of compartments, frequency and your procedure. Take acceptable values from the equipment manufacturer documentation and applicable standards.
