Resumo

MARTINS, M. Augusta G.. Falhas catastróficas em transformadores provocadas pelo sulfureto de cobre. Causas e Soluções. C.Tecn. Mat. [online]. 2008, vol.20, n.3-4, pp.8-14. ISSN 0870-8312.

Copper Sulphide (Cu₂S) deposition on the transformer windings (copper conductor and associated insulating paper) has recently led to catastrophic failures of transformers, in service. The description of this problem and the main questions we need to answer, urgently, in order to solve, or at least to minimize it, are presented here. The urgent need of “design” (formulation) of oils suitable for transformers for special applications and also the development of a new test method for the proper identification of the corrosive oils, susceptible to cause this type of failures, in transformers, are also referred. Finally, the state of the art about the use of a copper passivator dissolved in oil, as a way to mitigate the problem of Cu₂S deposition, the several questions about the way it works and the role played in the passivator performance by several  factors, are mentioned here, as well.

Palavras-chave : Copper Sulphide; Cu₂S; Failure; Corrosive Sulphur; Insulating oil; Passivator; Irgamet 39; Insulating paper; Electrical fault; Transformer.

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