Research on the electrical insulation design of a bushing for a 154 kV class HTS transformer

The cryogenic high voltage bushing for a 154 kV/100 MVA high temperatures superconducting (HTS) transformer is described. The bushing is energized with the line-to-ground voltage between the coaxial center and outer surrounding conductors, in the axial direction there is a temperature difference between ambient and 77 K. Therefore, it has to endure for electrical insulation as well as the thermal contraction as well.

In this research, the electrical insulation characteristics of GFRP to achieve high durability in the cryogenic environment were surveyed in the air and LN₂. Moreover, the insulation constructions of the commercial condenser type bushing were studied. Based on these data, the electrical insulation design of the cryogenic condenser type bushing for a 154 kV class HTS transformer was performed.