Tests and Performance Analysis of 2G HTS Transformer

Transformers represent one of the oldest and most mature elements in a power transmission and distribution network. The new superconducting transformers are smaller and lighter than conventional ones and they have lower power losses. Also, the new 2G superconducting tapes with high resistivity in the normal state allow to build transformers with high short-circuit strength. The short-circuit current limiting feature of the superconducting transformer, which is the most important benefit of replacing conventional windings by superconducting ones, provides protection and significantly reduces the wear and tear of circuit breakers and other substation power equipment. This paper describes the design and test results of a model of a 1-phase, 8.8 kVA superconducting transformer with windings made of 2G HTS tape. The authors also present the results of a numerical analysis of the design. A special regard is given to the ability of the device's superconducting winding to limit the short-circuit current, in particular its resistivity in normal state at a temperature of 77 K.