Construction and testing of a next generation HTS partial-core transformer
In 2005 the development of a 50Hz, 15 kVA, 230V:115V high temperature superconductor (HTS), partial core transformer was completed. The transformer was designed purely as a proof of concept, rather than as a unit that would be put into service. The transformer windings were layer wound using Bi2223 HTS tape from American Superconductors. The transformer failed while testing under full load with the internal primary winding failing to open circuit. This prompted an investigation into the cause of failure. Results from the investigation suggested the cause of failure to be a combination of operating near critical limits and insufficient cooling of the windings.
This paper presents the design, construction, and testing of a next generation HTS partial core transformer. The design is based around the original 15 kVA HTS transformer with a new winding insulation system allowing improved cooling of the HTS wire. The windings are layer wound with first generation Bi2223 high temperature superconductor from Trithor Germany.
A series of electrical tests were performed on the transformer including, open circuit, short circuit, resistive load, overload, ac withstand voltage, and fault ride through tests. The tests were conducted using international transformer testing standards as a guide where applicable. The transformer was found to be 98.2% efficient at rated power with 2.86% voltage regulation.