The development of a Roebel cable based 1 MVA HTS transformer

This paper describes recent experimental results in a continuing program to develop a 1 MVA demonstration transformer that employs HTS Roebel cable for the high current windings. The electrical design parameters of the transformer are presented, including the configuration of the specially developed Roebel cable. This paper discusses estimation of the cable Ic from measured Ic(B) data for samples of the strands, AC loss minimization using flux diverters, proving the suitability of the polyimide insulation scheme to withstand the effects of a high voltage impulse and modelling and experimental verification of the fault current limiting behaviour expected from the HTS conductor.