Application of patented technology for solving the problem of PCB contamination and corrosive sulfur in power transformers

Abstract

The exploitation of PCB contaminated power transformers and those which contain corrosive sulphur is related to the greatest risks to the environment, due to possible environmental accidents and faults and failures of transformers. The equipment contaminated with PCB require special attention, more frequent testing of transformer condition and control of oil leaking, while for corrosive oils standards and requirements defined in CIGRE TB 378, CIGRE TB 625, IEC 60296 and IEC 60422 are restrictive for the use of corrosive oils. Overview of the problems with PCB contaminated equipment and corrosive sulphur is provided in accordance to the latest knowledge in these areas. PCB decontamination, desulfurization and oil regeneration process is described by the application of patented technology developed in the 'Nikola Tesla' Institute. Summarized results of decontamination process of 310 PCB contaminated power transformers with different voltage levels and power and removal of corrosive sulphur from 29 transformers show the efficiency of this process for simultaneous removal of PCB, corrosive sulphur and oil ageing products.

Keywords

• power transformer
• polychlorinated biphenyl's (PCB)
• corrosive sulphur
• dibenzyl disulphide (DBDS)
• dechlorination
• desulphurization
• regeneration