Investigation of S/sub 2/F/sub 10/ production and mitigation in compressed SF/sub 6/-insulated power systems

The Cooperative Research and Development Agreement (CRADA), established to study the production and mitigation of S/sub 2/F/sub 10/ (disulfur decafluoride), one of a number of toxic by-products formed in electric discharges in the insulating gas SF/sub 6/, is described. The particular concern about S/sub 2/F/sub 10/ is due to its highly toxic nature, the ceiling limit value being 10 parts per billion (ppb, or 1 part in 10/sup 8/), and the need for development of sensitive detection techniques down to this level. In the presence of an electrical discharge such as an arc, spark, or corona, a portion of the SF/sub 6/ decomposes into lower fluorides of sulphur which can react to form a number of chemically active by-products including SOF/sub 2/ and SO/sub 2/F/sub 2/. During the maintenance or repair of SF/sub 6/-insulated equipment, the handling of these gaseous is a matter of concern. Preliminary arc experiment results, reported health-related incidents caused by SF/sub 6/ by-products, and ongoing studies are discussed.<>