Transformer Short Circuit Failure Case Histories

Short circuit events contribute to transformer failures (12% of all transformer failures according to CIGRE Technical Brochure 939 on Transformer Reliability). Transformer short circuit failures typically cause catastrophic damage to the transformer windings requiring the transformer to need new windings or for the transformer to be replaced. For this reason, a large portion of the transformer electrical design effort is focused on calculating the possible internal short circuit forces and designing the transformer windings to be strong enough to sustain the huge resulting mechanical forces. The investigation and repair of actual transformer short circuit failures can provide insight into the transformer short circuit phenomena and improvement / validation of transformer design rules. This…