Moisture Level of SF6 gas

By definition moisture in SF6 gas must be very low. The only reference I found stated that 70 ppm is the spec they require for their "puffer" style interruptors. There are a couple 'styles' of SF6 interruptors. One is a chamber pressurized with the gas and the other is a vacuum bottle that 'puffs' a blast of SF6 when a fault occurs. Another thing you will need to know is that after an interruption some portion of the SF6 gas will turn to SF5O2. This gas must be handled with care as it is very toxic.

Thanks for the information. My sub station handle 123KV supply from our local power generation station. I have 2 incoming lines of 132KV where both breakers and isolators for the incoming and outgoing to my power transformers is conseal inside the GIS system(Gas Insulated System). This system is very compact and space saving for my sub station. But lately I discover that few unit of my GIS switchgears compartment, the moisture of the SF6 gas has increased to 10 ppm. The rest of the compartment still maintain at -19 ppm to -13ppm. I would be much appreciate if somebody can provied me with some data for the moisture level recorded of the SF6 gas inside the GIS system for my reference so I can planned for the SF6 gas replacment.

Dear Simon, First , please informed how you did (methode) the measurement (direct presure or reducing pressure and are you using sensor type, mirror or others. second: you indicated your measurement 10 ppm, others -19 tp -13 ppm. Please clarify is it ppm or dewpoint? if you could informed this two , I could give you some information. Kind regards, Cawir GINTING PT. SF6 TEch International Service Provider of HV GIS SF6 Telp: +62 21 7788 2315 Fax: +62 21 7788 7367 email : cawir@singnet.com.sg