PD IEC/TR 62697 is an international standard that discusses fluids for electrotechnical applications.
PD IEC/TR 62697-3 is the third part of the multi-series that specifies a test method for the quantitative determination of elemental sulfur in used and unused insulating liquids over a 2 mg kg–1 to 400 mg kg–1 concentration range.
PD IEC/TR 62697-3 on a determination of elemental sulfur is relevant to:
Sulfur can be present in insulating liquids in various forms, including elemental sulfur, inorganic sulfur compounds and organic sulfur compounds.
The test method in PD IEC/TR 62697-3 describes the determination of elemental sulfur in insulating liquids for analysis.
The most common form of elemental sulfur is the octacyclic form with formula S8. If present, elemental sulfur can react with copper and other metal conductors in transformers, reactors and other similar devices to form copper and other metal sulfides. Therefore, this compound is classified as potentially corrosive sulfur. Elemental sulfur is present in petroleum and may be present in insulating mineral oils at concentrations ranging between 1 mg kg–1 and 400 mg kg–1, but it may be present at levels outside this range, in oils that have been blended, or oils in which elemental sulfur has been consumed through its reaction with the copper or other metals.
PD IEC/TR 62697-3 can thus be used for detecting and quantifying elemental sulfur content in used and unused insulating liquids.
IEC/TR 62697-3:2018