Organic Coatings for Corrosion Protection of Transformers in Underground Chambers

摘要

Underground electrical transformers are frequently submitted to a very aggressive environment because of the stagnated water of underground chambers which is heated and contaminated. In Brazil, carbon steel structures of underground transformers are usually protected with coal tar paints in order to ensure their reliability. However, the use of this type of paints is being strongly restricted because coal tar contains complex mixtures of polycyclic aromatic hydrocarbons which contain many toxic and potentially carcinogenic substances. Aiming at replacing coal tar based paints by an environmentally friendly one; several paints were selected in the local market and submitted to performance tests in order to compare them with coal tar based paint. In addition, anodes were evaluated to study the application of galvanic cathodic protection in areas of metal exposure due to coating flaws. This paper presents and discusses the obtained results.