Design And Study On A Single-Phase High Temperature Superconducting Partial-Core Transformer

During the past decades,a number of high temperature superconducting(HTS)transformer prototypes have been designed,and the majority of them are full-core transformers and air-core transformers.A 1 MVA HTS transformer is under preliminary research in Shanghai Jiao Tong University,and all these three types of transformer are candidates.In this study,a HTS partial-core transformer is proposed,where the iron core is different in that the limbs and connecting yokes are absent.It is a cylindrical iron core.To investigate the performance of this type of HTS transformer,we design and fabricate a single-phase HTS partial-core transformer prototype using the secondary generation(2G)HTS GdBCO wires.The iron core is at room temperature,and the windings are immersed in liquid nitrogen.The structures of primary and secondary windings are four layers connected in series and nine double pancakes connected in parallel,respectively.Fundamental characteristics are obtained by standard short-circuit,no-load and load tests at liquid nitrogen temperature of 77 K.In addition,the mathematical calculation of magnetic flux density of HTS air-core transformer is given,which is compared with that of the HTS partial-core transformer by circuit-coupled model.As a result,the magnetic field property of HTS partial-core transformer is presented.The detailed results about the design and experiments of the HTS partial-core transformer are presented and discussed in this study.