EDP ​​Portugal qualifies Sea Marconi thanks to treatment against corrosive sulphur.

S ea Marconi has recently intervened to treat a transformer in a central hydroelectric production in the North of Portugal owned EDP (Energias de Portugal), one of Europe's largest energy producers and one of the largest industrial groups in Portugal. The brilliant results of the activity earned Sea Marconi the formal qualification from EDF (Labelec) for the "regeneration" of insulating oils in electrical transformers.  

In more operational terms, the transformer treated was built in 1953, with an output of 7.5 MVA, a voltage of 70 KV and a oil quantity of 6,300 kg. The activity on the transformer was necessary for the presence of critical " corrosive sulphur from DBDS- C1". The main indicators of the critical issues encountered are the DBDS content in oil, which in this case was 76 mg / Kg, and the CCD test, which turned out corrosive.  

Sea Marconi solved the problem through Selective Depolarisation against DBDS , a kind of dialysis for the transformer. In summary, through the use of modular systems (MDUs) built by Sea Marconi, the oil is suctioned cyclically from the transformer, decontaminated inside the DMUs using patented reagents, and pumped back into the transformer in improved conditions. In this way, the transformer is never emptied of its oil load and, thanks to the constant flow of oil inside the transformer casing, the latter also benefits from superficial "cleaning" of insulating papers and on the casing bottom.

Sea Marconi's Selective Depolarisation treatment carried out in Portugal, which lasted from 25 June until 2 July 2015, took place on-load, that is, keeping the transformer in service and under load during the entire activity.

The customer monitored all phases of the treatment and, using its own laboratory (Labelec), carried out its own analysis of the oil at treatment end. In this instance, the DBDS shifted to <5 mg / kg the CCD test became "non-corrosive" and all other parameters were found to comply with IEC 60422.

The results surprised and fully satisfied EDP which, as noted above, formally qualified the Sea Marconi process for the "regeneration" of insulating oils in electrical transformers.