Experimental Studies of a High-temperature Superconducting Prototype Transformer with Current Limiting Function

The discovery of high-temperature superconductivity (HTS) is one of the most promising trends for the designing of electrical equipment. This paper presents experimental studies of the main electrical parameters of the developed prototype transformer with a dielectric medium in the form of liquid nitrogen (at 77 K). As the material for the transformer windings, the superconductor Y
₁
Ba
₂
Cu
₃
O
₇
(YBCO) was used. The presented mathematical model of the behavior of an HTS transformer during a transient process has been verified with high accuracy by experimental studies. The results of our investigations confirm that transformers with high-temperature superconducting windings have a unique function of limiting short-circuit currents, reducing them by three times compared to conventional transformers. It is determined that the short-circuit current limitation is most effective when the critical current value of the superconductor is exceeded several times.