A new type of dry power transformer based on XLPE cable winding

This paper summarizes a new type of dry transformer, which is developed firstly by ABB, whose brand name is dry former. Dryformer is produced by combining modern high voltage XLPE cable technology with conventional transformer. The following conclusion can be derived from the analysis of construction features of the new type dry transformer: compared with the traditional transformer, it has the following advantages, high voltage rating, large capacity, combustion retardation, better performance to endure very fast transient voltage stress and lower line losses. The technique of solid insulation is adopted in the new dry transformer so that the pollution from leakage of insulating oil can be avoided, and so XLPE cable-winding transformer is very suitable in environment sensitive places such as populous cities, hydropower stations, and underground caver and so on. It is a developing trend of high voltage dry transformer