Influence of charge behavior on breakdown strength of kraft paper in liquid nitrogen

High temperature superconducting cable (HTS cable) is expected as one of the solution to deal with the increase of power demand. Insulation structure of HTS cable is mainly insulating paper - liquid nitrogen composite system. In general, DC power transmission has good affinity for long distance power transmission and is also able to take advantage of the superconducting property. However, DC HTS cable may raise the problem that the charge injection can degrade the insulating performance, which is the same as the problem in existing oil immersion cables for DC. In this paper, we investigated the influence of charge behavior on the breakdown strength of the insulating paper in liquid nitrogen by changing the air resistance of insulating paper.