Creep Failure and Prevention in Aluminum Wound Distribution Transformers

This paper presents an experimental study on electrical properties and creep behavior of thermo-mechanically processed 6060 aluminum alloy wire to assess its suitability as a winding conductor in place of electric conductor grade aluminum wire in distribution transformers. Electrical resistivity and the stress exponent and activation energy for creep were measured for both thermo-mechanically processed 6060 aluminum alloy and electric conductor grade aluminum wire. An algorithm is given for estimate the life and switching capability of the distribution transformers considering creep. The results of this study can be used as a guide to select the creep resistant winding material for designing and producing reliable distribution transformers and is valuable especially in power deficient areas, poorly designed and haphazardly expanded power distribution networks where repeatedly energized aluminum wound distribution transformers may fail due to creep in the high voltage winding conductors.