SF6 Diagnostics and Solutions

Sulphur hexafluoride (SF6) is a non-toxic, odourless gas with unique electrical properties. For over 50 years, it has been used in high-voltage gas-insulated switchgear (GIS), where its excellent dielectric and arc-quenching properties make it an ideal insulating gas for medium- and high-voltage equipment.

However, when the gas decomposes, it forms decomposition products that are toxic to maintenance personnel and harmful to equipment. As gas-insulated electrical equipment ages, electric utilities need efficient diagnostic procedures to assess the quality of in-service SF6 to prevent failures, extend equipment life, reduce maintenance costs, and increase personnel safety. In addition, environmental concerns about SF6 require improving handling practices, this includes accurate field assessment of SF6 gas.

Powertech Labs’ analysis of SF6 gas can provide electric utilities with invaluable information essential for safe handling and proper equipment operation. Of particular interest is the gas’s potential as a diagnostic technique for in-service equipment. Knowledge of the nature and relative amounts of SF6 by-products can be used to determine the operating condition of the equipment, to locate faults, and to detect incipient faults in GIS.

Powertech can also perform analysis on SF6 gas for purity (including blend composition), decomposition products, and moisture. In addition, Powertech has the capability for complete on-site chemical analysis using a portable gas chromatograph and/or with Powertech’s decomposition products detector. Together, these two analyzers offer the ability to completely assess, in real time, in-service gas to criteria as set by CIGRE (for recycled gas) and IEC (for new gas).

Powertech Labs’ SF6 services:
• SF6 Analysis
- Impurities – ASTM D2685
- Decomposition Products
- Moisture
• Field Assessment of SF6-Filled Equipment
• SF6 Capture of Leaks
• Research into Utility Use of SF6
• Consultation

Powertech also offers the following training:
• SF6 Gas Fundamentals, Safety and Handling
• SF6 Gas Sampling, Analysis and Diagnostics
• Clean-Up and Decontamination of Failed SF6 Equipment

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