Secondary (low-side) surges in distribution transformers

The Task Force was formed in response to a proposal that a secondary, or low-side, current surge withstand design test be included in the IEEE test standards. It was charged with reviewing all information on low-side surges and determining if revisions of dielectric tests of distribution transformers are indeed warranted. Although agreement on a standard test has not been reached, substantial work has been done and is summarized. The problem of failures of distribution transformers due to low-side surge phenomena is described, and how it is being addressed by the industry is detailed. The problem is described in historical perspective along with the varied viewpoints of the Task Force members. The system and transformer parameters that influence the problem are discussed. Proposed solutions and their tradeoffs are presented. A reference list of published literature is provided.< >