The New Concept of Using the Superconducting Transformers in Low- and Medium-Voltage Distribution Network

The new 2G HTS tapes with high critical current and high resistivity in the normal state allow building low-cost transformers with high short-circuit strength for the low and medium power distribution substations. The authors consider that currently the best chance of the commercial applications have transformers, which rated currents of their windings do not exceed or slightly exceed the critical current of used superconducting tapes. Such units could be the low- or medium-voltage transformers with a power less than 10 MVA, where the high-voltage winding can be made with a single HTS tape while the low-voltage winding can also be made with a single HTS tape or two-three tapes connected in a parallel. This eliminates the need of a tape transposition or an application of Roebel's cable. Superconducting transformers could stabilize the low or medium power network and increase the connectivity of renewable and dispersed energy sources. This paper presents an analysis of the possibility of using the low- and medium-voltage superconducting transformers. Such units could be, e.g., transformers working with renewable energy sources.