Development of High Performance Electrical Insulation System of Superconducting Power Apparatus by Polymeric Composite Materials

研究人员一直在研究聚合物材料（乙丙橡胶（EPR））在超导电力设备电气绝缘系统中的应用。在低温下，对液氮、液氦等流体的绝缘研究很多，但对高电压下固体绝缘的研究很少，主要研究结果如下：（1）在EPR的情况下，填充塑料除了在低温下具有可控的热收缩外，还具有优良的电性能。(2)直流电绝缘系统用填充EPR样品的电击穿和空间电荷表明，低温击穿强度远高于室温击穿强度。这可能归因于电极的损耗载流子注入，并为超导电力设备的电绝缘设计提供了强有力的激励。(3)EPR材料在低温和室温下的抗树枝化性能以及填料对抗树枝化性能的影响表明，EPR材料在低温下具有足够的抗交流树枝化性能，而填料对抗交流树枝化性能的改善作用不大，这为聚合物材料（EPR）在超导电力设备电绝缘系统中的应用开辟了一条途径。EPR是一种很有前途的低温固体绝热材料。

The investigators have been studying the application of polymeric materials (ethylene-propylene rubber (EPR)) to electrical insulation system of superconducting power apparatus. At cryogenic temperature, there are many practical insulation studies on fluids such as liquid nitrogen or liquid helium but scarce studies on the solid insulation enabling a high voltage design.The results are summarized as follows:(1) Plastics with fillers, in the case of EPR, give excellent electrical performance in addition to the controlled thermal contraction at cryogenic temperature.(2) The electrical breakdown and space charge of EPR samples with fillers for the DC electrical insulation system showed that the breakdown strength at cryogenic temperature is much higher than that at room temperature. This may be attributed to loss carrier injection from electrode and gives a strong incentive to design the electrical insulation of superconducting power apparatus.(3) The EPR resistance to treeing both at cryogenic and room temperatures and the effect of fillers on resistance to treeing showed that EPR has sufficient resistance to AC treeing at cryogenic temperature and the fillers improve resistance to AC treeing slightly.The results obtained in this study open an avenue to the application of polymeric materials (EPR) to electrical insulation system of superconducting power apparatus. EPR seem to be promising materials for solid insulation in the cryogenic region.