SF6 is often used as a dielectric and arc-suppression medium in gas insulated equipment (GIE). Most manufacturers of GIE’s recommend maximum and minimum tolerances for certain variables within the gas, including moisture, gas decomposition, and purity of SF6.
Exceeding the GIE recommended moisture levels will cause formation of acidic by-products, such as HF, SO2, SOF2, etc. Therefore, it is important that end-users measure the SF6 moisture content with reliable, cost-effective, and durable moisture analyzers.
All test equipment requires that the sample gas be dissipated. Thus, the longer the equipment takes to perform an accurate reading, the more valuable gas is wasted; in addition SF6 gas is detrimental to the earth’s ozone layer. The gas can be recaptured at the exhaust port of some equipment.
Moisture analyzers for GIE’s should be able to address all of the concerns, of measuring in corrosive environments, wide temperature fluctuations, within the pressures found on different GIE’s and SF6 bottles, minimize gas waste by rapid accurate measurement.
IEEE 1125-1993 “IEEE Guide for Moisture Measurement and Control in SF6 Gas-Insulated Equipment” is a good starting point in assessing the moisture analyzer requirements.

The PhyMetrix PPMa was specifically designed with these measurement requirements in mind.
The PPMa is ideal for the power industry’s moisture measurement requirements in SF6, N2, Air and other gases because of its unique features:

• High Accuracy over a wide measuring range -110°C to +20°C
• Speed of Response
• Saving valuable service technician time
• Minimizing waste of environmentally harmful and costly gas
• Ability to recapture exhausted gas
• Low Cost of Ownership
• Small, lightweight, rugged, weatherproof
• Perfect for testing in tight spaces and above ground locations
• Field analyzer designed for use outdoors
• Extremely Easy to Operate, with intuitive graphical user interface
• On screen graph indicates when measurement is stable
• Powered by a rechargeable battery
• Data logging (single point or continuous) with location/operator tags
• USB interface for transferring logged data to MS-Excel® spreadsheet
• Resistant to Contaminants common in field measurements e.g. HF, F2, SO2, SOF2, oil vapor
• Superior Reliability
• Expert prompt support from PhyMetrix engineers
• Training software available for technicians to practice on the use of the analyzer at their convenience