Electrical insulation design and withstand test of model coils for 6.6 kV class HTSFCL

Electrical design and withstand test of mini-model coils for high temperature superconducting fault current limiter (HTSFCL) have been studied. Electrical insulating factors of the HTS coil for HTSFCL are turn-to-turn and layer-to-layer. The electrical insulation of turn-to-turn depends on surface length, and the electrical insulation of layer-to-layer depends on surface length and breakdown strength of LN₂. Therefore, two basic characteristics of breakdown and flashover voltage were experimentally investigated to design electrical insulation for 6.6 kV Class HTSFCL. We used Weibull distribution to get electric field strength for insulation design. And mini-model coils for HTSFCL were designed by using Weibull distribution and were manufactured to investigate breakdown characteristics. The mini-model coils were passed in impulse withstand test as well as AC withstand test.