Experimental and numerical study on an HTS air core transformer with pancake structure
This paper presents the characteristic tests and electromagnetic analysis of a single-phase high temperature superconducting (HTS) air core transformer prototype. Single pancake (SP) windings with GdBCO coated conductors were used in this transformer. The primary windings were six SPs connected in series and the secondary windings were three SPs connected in parallel. Fundamental, loss and critical current characteristics were obtained by no-load and load tests. A field-circuit coupled model built in COMSOL was used to analyze the electromagnetic characteristic of this transformer. The experiment results were in consistent with the simulation values. The numerical model was validated, and could be applied in engineering. Finally, the circulating currents with and without an iron core were calculated. The transformer with an iron core has a smaller circulating current than that of without an iron core.