A Reason for “Corrosive Sulfur” Failures

It has long been the accepted opinion that it is the DBDS additive that causes the majority of failures in modern transformers manufactured up to 2007 when the use of this antioxidant was discontinued by most of the oil manufacturers that had chosen to use DBDS. Since long, whenever a failure occurs and the Covered Conductor Deposition test (CCD) comes out positive, DBDS is blamed. However, this enormous simplification of reality has not been accepted by all. Independent research has been carried out for the purpose of giving a less prejudice picture of the situation. With this research results, in conjunction with the in-depth failure analysis of one transformer that presented all the signs which characterize a corrosive sulfur it has become clear that corrosive sulfur failure depending on DBDS and other sulfur based additives may well be a myth. The same research also strongly indicate that Irgamet® 39 cannot possibly be a copper passivator and this is exemplified by purely logical reasoning. This paper also briefly discuss stereochemical and as far as literature searches performed by the authors never before mentioned aspect regarding why lrgamet® 39 will never function. Irgamet® 39 was used to attempt to mitigate the corrosive sulphur effect by DBDS in this transformer which failed. Stereo-chemistry, molecule reactivity and literature searches has instead shown DBDS to be a passivator in the true sense or the word.