Superficial protection and cathodic protection of underground electrical transformers

Abstract:

Carbon steel structures for underground electrical transformers are often subject to severe corrosion due to exposure to contaminated and heated stagnated water found in underground chambers. Therefore, they are continually maintained which requires high costs and sometimes in affects the power supply. To overcome this problem. AES Eletropaulo and IPT are developing a study with the specific aim of establishing technical specifications for products and services to replace the current paint (coal tar epoxy) for higher performance and environmentally friendly paints. Additionally, the study includes the use of cathodic protection in conjunction with the selected painting systems. In this paper, the adopted methodology as well as the obtained results are presented and discussed. Four new organic paints were evaluated. For comparison, the current used painting system was included. Accelerated corrosion tests and immersion tests in water collected from the field and in a saline solution were performed to evaluate the performance of the selected painting systems. A specific test for the selection of a galvanic anode for the cathodic protection system was also performed. Among the tested painting system, two considered more appropriate for the replacement of coal tar epoxy based system and aluminum anode identified as the best for sacrificial anodes. Currently, nonaccelerated tests are being conducted in the field to validate the results obtained in the laboratory.


Reference:
ARAUJO, Adriana de; MARTINS, Clay M.; PANOSSIAN, Zehbour; ALMEIDA, Neusvaldo Lira de; DIAS JR., Alberto S. Proteção superficial e produção catódica de transformadores elétricos subterrâneos. In: CONGRESSO INTERNACIONAL DE CORROSÃO, INTERCORR 2012, 32., 2012, Salvador. Anais…Salvador: ABRACO, 2012. 14p.

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