Copper-wound Transformers were proven tested to be reliable and were used by utilities years ago, because of its low-cost and capabilities. However, with their high cost nowadays, we plan to use Aluminum-wound transformers. Based on facts, aluminum's characteristics in terms of its electrical and mechanical capabilities can equalize that of copper's, given some enhancements.. However in actual set-up in the field, is aluminum-wound transformers, especially wire connections, internal and external, reliable and safe from breakdown or damage due to mechanical, thermal and electrical stresses? Also, Do aluminum transformers have higher transformer and insulation life? I need your expertise and point of view on this matter. Thanks a lot!