Corrosions & PCBs: Inventory, Diagnostics and Treatments of Oils and Transformers

Abstract

This paper describes the “State of the Art” for inventory, diagnostic, prognostic and integrated treatment of electrical equipment and insulating liquids containing DBDS/Corrosions & PCBs (Tech Pathologies).The Corrosions determine a functional risks for transformers and equipment filled with mineral insulating oils: C1-DBDS & Corrosive Sulfur; C2-NOT DBDS & Corrosive Sulfur; C3-.SCBP & Corrosive Sulfur; C4-NOT Corrosive Sulfur & Metal Dissolution. The PolyChlorinatedBiphenyls (PCBs) are a “Persistent Organic Pollutants” (POPS), as “Class 1.Cancerogenic to humans (IARC 2013) and determine risks for workers, public health and environment.The oils & transformers integrated treatments, PCBs dehalogenation technique (“DMU & CDP Process” patented by Sea Marconi) and DBDS Selective Depolarization, in continuous mode through a closed circuit process are the sustainable solutions (Therapies) based on “circular economy”.These solutions are based on the use of Smart Decontamination Modular Units (DMUs) and a solid reagent, consisting of a higher molecular weight glycol compounds, a mixture of bases and radical promoter or other catalyst on a high surface area particulate support. These processes normally run at $80- 100^{\circ}C$ and have the capability to decontaminate equipment on-site through continuous circulation of the oil in a closed system (without draining the oil or using auxiliary tanks), using the solvent capability of the oil for continuous extraction of PCBs and DBDS from solid materials inside the equipment (according IEC 60422 art. 11.4.4).International experience of diagnostic, prognostic and integrated treatments are presented according to IEC & CENELEC include On -Load treatments in power transformers and shunt reactors, in several countries.