Development of High Performance Super-conducting Model Power Cable with Extruded Polymer Insulation Considering DC Power Transportation

本研究所开发的电力电缆是一种高性能的超导电力电缆，考虑到直流电力输送的挤出聚合物绝缘。将铋系超导体以带状排列在芯铜管上，外覆乙丙橡胶（EPR）绝缘层，绝缘层由内、外两层半导体组成，研究结果如下：（1）对超导带材在稳定铜管上的最佳排列方式进行了尝试，在反复冷却至低温的试验中，证实了超导带材与稳定铜管的接触状态稳定。(2)EPR绝缘材料在冷却到液氮温度时不受热应力和机械应力的影响。采用与电缆的冷缩性和柔性相对应的SZ屏蔽层，降低了电缆在低温下的介质损耗角正切。(3)使用SZ线屏蔽，在短长度和长长度电缆样品中获得大致相同的tan δ特性。(4)计算电缆的介质损耗，每1m电缆的介质损耗约为0.013W。该介电损耗与超导体的交流损耗相同。本研究结果为聚合物材料（EPR）应用于超导电力设备的交流和直流电绝缘系统开辟了一条新的途径。EPR是一种很有前途的低温固体绝热材料。

The electric power cable which was developed by this research is high performance super-conducting power cable with extruded polymer insulation for considering a DC power transportation. Arranging super-conductors (the bismuth type) formed in tape-shape on a core copper pipe, it is covered by the ethylene propylene rubber (EPR) insulation which includes inner and outer semi-conducting layers.The results are summarized as follows :(1) Attempting a best arrangement on the stabilization copper pipe of the super-conductor tapes, their contact situation was confirmed to stable during the examines of repeated cooling to cryogenic temperature.(2) The EPR insulation did not suffer from the thermal and mechanical stresses from cooling process to liquid nitrogen temperature. Using SZ wire shield which correspond to cold shrinkage and flexibility of the cable, dielectric loss tangent delta of the cable was reduced at cryogenic temperature.(3) Using SZ wire shield, the characteristic of approximately the same tan 6 was gotten in both short length and long length cable samples.(4) Computing the dielectric loss of the cable, it was about 0.013 W for every 1 m of cable. This dielectric loss was as same as the AC loss of the super-conductor. Itwas more than 1 digit lower compared with the invasion heat from outside of the cable radius direction.The results obtained in this study open an avenue to the application of polymeric materials (EPR) to electrical insulation system of super-conducting power apparatus for both AC and DC conditions. EPR seems to be promising material for solid insulation in the cryogenic region.