In 2005, the Sea Marconi laboratory discovered the cause of numerous faults generally attributed to corrosive sulphur, identifying DBDS(Dibenzildisolfuro) as the principal factor; this additive is used to improve the quality of the oils, however it is very dangerous due to its affinity with the copper. To summarise: the DBDS binds with the copper present inside the transformer, forming copper sulphide. This conductive compound has a tendency to detach from the copper surfaces and deposit on the cards, which gradually lose their insulating properties, resulting in the risk of dangerous electrical discharges.

A few months after discovering DBDS, and the associated failure mechanisms, Sea Marconi Research surprised the market by offering a solution to this problem: Chedcos Selective depolarisation ®. This process eliminates the corrosive sulphur contaminants, such as DBDS, from the oil and blocks the formation of copper sulphide, while simultaneously restoring the original physical-chemical properties of the fluid (acidity, Tg-delta, dissolved metals) without the need to replace the oil or empty the transformer, even partially. Thanks to the use of mobile units (DMU), the oil is filtered, dehumidified, degassed and depolarised of any corrosive compounds by using Sea Marconi's patented reagents. Upon completion of the treatment.

Sea Marconi carries out a fresh analysis on the insulating oil to ensure that it has been decontaminated and that the DBDS have been eliminated. Currently, Sea Marconi's Selective Corrosive Sulphur Depolarisation process is the only effective and lasting solution to the problem of the corrosivity of oils.