35kV超导电缆终端电流引线的绕包型绝缘设计

Lapping Insulation Design of Termination Current Lead for 35 kV Superconducting Cable

目前电流引线大多采用挤包型绝缘结构,为改进引线绝缘性能,提出对35kV超导电缆终端电流引线采用绕包型绝缘结构设计。选择了一种在低温条件下仍具有较好电气性能和机械性能的聚丙烯层压纸(LPP)对电流引线进行绕包,并等间距地加入铝箔作为电容屏以改善电流引线的电场分布。通过计算和仿真分析可知,加入4层铝箔对绝缘层电场分布的改善效果最为显著。电气性能测试表明该35kV电流引线完全符合电气性能要求。该绕包型绝缘设计的特点为:绝缘层可以骤冷,且不会遇低温开裂;改善了轴向与径向电场和绝缘层的抗电老化性能,提高了绝缘层的击穿电压。

Most of current leads adopt the solid insulation design.We designed a lapping insulation of termination current lead for 35 kV superconducting cable to improve insulation of the leads.Laminated polypropylene paper（LPP）,which has good electrical property and mechanical characteristic under cryogenic conditions,was selected as the lapping insulation material of current leads.Then,aluminum foils were placed between the layers of polytetrafluoroethylene film with equal intervals to improve the electrical field distribution in current leads.Through calculation and simulation analysis,it is concluded that setting 4 layers of aluminum foil has the best effect.With electrical tests,electrical property of the proposed current lead under voltage of 35 kV is proved to meet the related electric requirements.The lapping insulation design of current lead has two prominent characteristics： the insulation lagging could sustain sudden cooling without cracking;the radial and axial electrical field and the anti-aging property are improved and the breakdown voltage is increased.