Electrical Insulation in Superconducting Power Apparatus

（1）阐明了超导电力设备失超环境下液氦击穿电压的劣化机理。根据失超后的热能、间隙长度和液氦压力，系统地描述了失超动态击穿特性，为超导电力设备的绝缘设计提供了理论依据。(2)制作了挤压型EPR绝缘直流超导电缆的试验模型，考察了EPR挤压对高温超导体特性的影响以及低温下EPR的直流电绝缘性能。结果表明，即使采用挤压EPR绝缘，高温超导体的特性劣化也很小。研究了乙丙橡胶在低温下的力学性能和直流电绝缘性能， ...更多信息 这些结果为今后利用挤压EPR绝缘直流超导电缆实现大功率输送提供了保证。(3)研究了超导汽轮发电机的电气绝缘设计。研究了高速旋转条件下液氦中氦泡的行为与液氦击穿特性的关系.B.超导磁体电绝缘材料耐压特性的评价（1）提高压力可显著抑制由液氮和固体绝缘材料组成的复合绝缘系统中的局部放电（PD）。环境温度对含人工孔洞固体绝缘子的局部放电特性有很大影响。在较高的电压应力下，绝缘体寿命在液氮温度下比室温下短得多。(2)在微重力环境下观察了液氮中气泡的运动，测量了电子在N_2/Ar混合气体中的漂移速度。在低场下，高分数N_2中的低迁移率电子被定域在某些多粒子中。(3)本文研究了在室温和低温（约93 K）下，均匀场间隙在50 Hz交流、直流和1.4/50微秒雷电冲击电压下的长间隙击穿电压。实验结果证实了帕邢定律在任何情况下都成立。(4)在氦气存在的条件下，研究了极有希望作为低温电绝缘体系的挤出聚合物在发生泄漏事故时的抗树枝化性能。结果表明，He气体在室温下降低树枝化电阻，但在低温下不降低。少

A.Evaluation of electrical insulation characteristics for superconducting power apparatus(1) Degradation mechanisms of breakdown voltage of liquid helium under quench environment of superconducting power apparatus were elucidated. The quench-induced dynamic breakdown characteristics were systematized by post-quench thermal energy, gap length and pressure of liquid helium, which will contribute to the practical insulation design of superconducting power apparatus.(2) The trial model of extruded EPR insulation DC superconducting cable was made and the change of the characteristic of the high temperature superconductor due to the EPR extrusion and the DC electrical insulation performance of EPR at cryogenic temperature were examined. It was shown that the characteristic deterioration of the high temperature superconductor was a little even if extruded EPR insulation was applied. The mechanical characteristic of EPR at cryogenic temperature and the DC electrical insulation performance have … More been approved excellent These results promise the realization of the huge power transportation by using the extruded EPR insulation DC superconducting cable in the future.(3) Electrical insulation design of superconducting turbo generator was studied. Relations between the behavior of helium bubbles in liquid helium and breakdown characteristics of the liquid were investigated in high speed rotating condition.B.Evaluation of withstand voltage characteristic of electrical insulating materials for superconducting magnets(1) Partial discharge (PD) generated in a composite insulation system composed of liquid nitrogen and solid insulation material is considerably suppressed by increasing pressure. PD characteristics in solid insulator with an artificial void are strongly influenced by ambient temperature. At a higher voltage stress, the insulator lifetime can be much shorter at liquid nitrogen temperature than room temperature.(2) The bubble motion in liquid N_2 in microgravity environment was observed and the drift velocity of electrons in N_2/Ar mixtures was measured. The low mobility electrons in high fraction of N_2 in low fields were shown to be localized in some multiparticle.(3) The longer gap breakdown voltages of a uniform field gap for 50Hz ac, dc and 1.4/50 micro-sec lightning impulse voltage applications in gaseous nitrogen and air are studied at a room temperature and a cryogenic temperature (about 93K). It is confirmed from the experimental results that the Paschen's law holds in any cases.(4) Resistance against treeing degradation of extruded polymer, which is promising as electrical insulating system at cryogenic temperature, was investigated under existence of He gas assuming leakage accident. It was clarified that He gas decreases treeing resistance at room temperature, but not at cryogenic temperature. Less