PD IEC/TR 62697 is an international standard that discusses fluids for electrotechnical applications.
PD IEC/TR 62697-2 is the second part of the multi-series that specifies a test method for the quantitative determination of total corrosive sulfur (TCS) in unused and used insulating liquids and solid matrices through the conversion of corrosive sulfur species to metal (copper, silver etc.) sulfides. The sulfides formed are quantitatively converted to sulfates; sulfates are determined through turbidity measurement or with ion chromatography.
Note: The method is not applicable for assessing corrosion phenomena for example the dissolution of copper in insulating liquids and deposition on solid matrices, which do not lead to sulfide formation.
PD IEC/TR 62697-2 on a determination of TCS 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 62697-2 describes the determination of TCS in insulating liquids. TCS is the sum of all elemental and chemically bound sulfur in an insulating liquid that reacts with metals such as copper under certain conditions to form sulfides. The method provides quantitative measure for total corrosive sulfur in insulating liquids rather than qualitative results obtained through current standard test methods for corrosive or potentially corrosive sulfur in insulating liquids.
As a result, you can avoid copper sulfide formation in transformers and other electrical equipment filled with insulating liquids.
IEC/TR 62697-2:2018