The introduction of technical standard IEC 62697-1 of 2012 (page 7) states that:

  • sulfur can be found in insulating liquids (used in transformers and other electrical equipment) in various forms
  • Total sulfur concentration depends on origin of the liquid, refining process, formulation and the presence of additives
  • There are non-corrosive sulfur compounds and others that are extremely corrosive for metal surfaces, such as those inside transformers
  • The presence of these corrosive sulfur species has been directly linked to failures involving equipment used in the generation, transmission and distribution of energy for several decades.
  • For this reason, the IEC standard has ruled that both new insulating oils and in-service oils must be free of these corrosive sulfur compounds

Along with the discovery of DBDS as the principle cause of the corrosive sulfur phenomenon (July 2005), Sea Marconi has also studied the corrosive action of both sulfur compounds that are normally found in oil and of products of the degradation of additives.

Sea Marconi's major publications on the topic:

M. Pompili, F. Scatiggio, V. Tumiatti, R. Maina, M. Tumiatti, Corrosive sulfur in insulating oils: its detection and correlated power apparatus failures, IEEE Trans. On Power Delivery, Vol. 23, No. 1, 2008


V. Tumiatti, R. Maina, F. Scatiggio, M. Pompili and R. Bartnikas, In Service Reduction of Corrosive Sulfur Compounds in Insulating Mineral Oils, ISEI 2008, Toronto, June 2008


F. Scatiggio, V. Tumiatti, R. Maina, M. Tumiatti, M. Pompili and R. Bartnikas, Corrosive Sulfur Induced Failures In Oil-Filled Electrical Power Transformers And Shunt Reactors, IEEE Trans. On Power Delivery, Vol. 24, No. 3, 2009


R. Maina, V. Tumiatti, M. Pompili and R. Bartnikas, Corrosive Sulfur Effects in Transformer Oils and Remedial Procedures, IEEE Trans. On Dielectrics and Electrical Insulation, Vol. 16, No. 6, 2009


R. Maina, V. Tumiatti, M. Pompili and R. Bartnikas, Dielectric Loss Characteristics of Copper Contaminated Transformer Oils, IEEE Trans. On Power Delivery, Vol. 25, No. 3, 2010


F. Scatiggio, R. Maina, V. Tumiatti, M. Pompili and R. Bartnikas, Long Term Stability of Insulating Mineral Oils Following their Corrosive Sulfur Removal, ISEI 2010, San Diego, June 2010


R. Maina, V. Tumiatti, F. Scatiggio, M. Pompili and R. Bartnikas, Transformers Surveillance Following Corrosive Sulfur Remedial Procedures, IEEE Trans. On Power Delivery, Vol. PP, Issue 99, 2011


M. C. Bruzzoniti, C. Sarzanini, R. M. De Carlo, R. Maina, V. Tumiatti, Guasti in trasformatori di potenza impregnati in olio minerale isolante e potenziali danni ambientali. Indagine su fenomeni di corrosione correlati a contaminazione da sostanze corrosive, Proc. XII National Congress of the Division of Environmental Chemistry and Cultural Heritage, Taormina (IT), September 2010, http://www. socchimdabc. it/joomla/documenti/atti_XII_congr. pdf


R. Maina, V. Tumiatti, M. C. Bruzzoniti, R. M. De Carlo, J. Luki?, D. Naumovi?-Vukovi?, Copper Dissolution and Deposition Tendency of Insulating Mineral Oils Related to Dielectric Properties of Liquid and Solid Insulation, ICDL 2011, Trondheim, June 26-30 2011


M. C. Bruzzoniti, R. M. De Carlo, C. Sarzanini, R. Maina, V. Tumiatti, Determination of copper in liquid and solid insulation for large electrical equipment by ICP-OES. Application to copper contamination assessment in power transformers, Talanta, Vol. 99, 2012, 703-711


R. M. De Carlo, M. C. Bruzzoniti; C. Sarzanini, R. Maina; V. Tumiatti, Copper Contaminated Insulating Oils-Testing and Investigations, IEEE Trans. On Dielectrics and Electrical Chim. Dott. Riccardo Maina Insulation, Vol. 20, No. 2, 2013, 557-563


R. M. De Carlo, C. Sarzanini, M. C. Bruzzoniti; R. Maina; V. Tumiatti; Copper-in-oil Dissolution and Copper-on-Paper Deposition Behavior of Mineral Insulating Oils, IEEE Trans. On Dielectrics and Electrical Insulation, Vol. 21, No. 2, 2014, 666-673


M. C. Bruzzoniti, R. M. De Carlo, C. Sarzanini, R. Maina, V. Tumiatti, Stability and Reactivity of Sulfur Compounds against Copper in Insulating Mineral Oil:Definition of a Corrosiveness Ranking, Ind. Eng. Chem. Res. , 2014, DOI: dx. doi. org/10. 1021/ie4032814