Comparison of Insulation Test of Mini-Models With Different Winding for a HTS Transformer

Recently, universities and companies are developing a power distribution and transmission class high temperature superconducting (HTS) transformer that is one of the 21st century superconducting frontier projects in Korea. For the development, it is necessary to establish the dielectric technology at cryogenic temperature such as insulating design, cooling system, manufacture, compact, and so on. Also, verification of insulating stability is one of important dielectric technology. Therefore, we prepared three models for a small simulated the HTS transformer, one is concentric arrangement, another is reciprocal arrangement, the other is Z continuous winding arrangement from Kapton insulated Cu tape and measured their insulation characteristics such as partial discharge (PD), AC (50 kV, 1 min) and impulse (154 kV, 1.2times50 mus) withstand test. Before manufacture each model, we have been analyzed insulation composition and investigated electrical characteristics such as breakdown of LN₂ , polymer and surface flashover on fiberglass reinforced plastic (FRP) in LN₂. We are going to compare with measured value and apply the value to most suitable insulating design of the HTS transformer