HTS in electric power applications, transformers

Abstract

With the discovery of the high temperature superconductors the prospect to find widespread applications of these conductors also in electric power applications grew very fast. The advantages that could be anticipated was reduced losses, reduced weight and volume plus less environmental impact. During the last five-six years techniques have been developed to produce long lengths of flexible conductors that can be used in cables or windings. Most manufacturers of high temperature superconductors concentrated on traditional DC applications. However, much larger markets will open up when good enough AC conductors become available for power applications. In 1994 ABB started a project aiming at a 630 kVA three-phase power transformer with windings made of high temperature superconductors. This transformer was taken into operation in the spring of 1997 and operated perfectly for one year. I will discuss the performance and price demands the high temperature superconductors have to fulfill to be useful in power applications and review the above mentioned transformer project and also give some insight in a running project with the goal to design, build and put in operation a 10 MVA power transformer with high temperature superconductors with low AC-losses in the windings.