Tapchanging - the transformer designer's perspective

Abstract

A power transformer is a static piece of electrical equipment and this may be a contributing factor behind its widely acknowledged reliability. Very often, it is equipped with an on-load tap-changer that has moving parts and creates electric arcs, by the very nature of its purpose. The tap-changer, therefore, presents a somewhat greater risk than the core and windings, the oil and the tank. Tap-changer technology has striven to increase integrity, reduce lifetime costs, and increase reliability and availability, by concentrating on quality. This paper describes how the transformer designer is seeking a quality manufacturer, with a well-proven product, at a competitive price that will attract the prospective transformer purchaser. The present day product, if obtained from reputable suppliers, goes far in meeting the ideal, but further developments are, and will always be, essential in the interests of product improvement. Transformer manufacturers, in accord with the tap-changer users, eagerly await those developments. They do, however, hope that heed is taken of their concerns in respect of dielectric proving, by the specification writers.