Dielectric characteristic of insulating paper - Ice composite material in liquid nitrogen

Paper-liquid nitrogen (LN2) composite system has been used as one of the insulating systems of the high-temperature superconducting cable. In this system, partial discharge may occur inside the N2 gas bubbles due to the gasification of LN2 in the paper. We have been suggesting the paper-ice composite material as one of the candidates for the insulating system with LN2 in high-temperature superconducting cables. The paper-ice composite material is an insulating paper filled with ice and it could inhibit the partial discharge inside the microscopic N2 gas bubbles remained in the paper. This research investigated capacitance and dielectric loss tangent of the paper-ice composite material with changing field strength. Finally, we clarified that the paper-ice composite material could provide lower capacitance system to paper-LN2 composite insulating system for high temperature superconducting cables.