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)在超导电力设备电气绝缘系统中的应用。在低温下，对液氮或液氦等流体的绝缘研究很多，但对固体绝缘的高压设计研究很少。研究结果总结如下：(1)在EPR的情况下，添加填料的塑料除了在低温下可控的热收缩外，还具有优异的电性能。(2)在直流电气绝缘系统中，添加填料的EPR样品的电击穿和空间电荷表明，低温下的击穿强度远远高于室温下的击穿强度。(3)EPR低温和常温下的耐树枝性能以及填料对耐树枝性能的影响表明，EPR材料在低温下具有足够的抗交流树枝能力，而填料对交流树枝的抗性略有提高。本研究结果为聚合物材料在超导电力设备电绝缘系统中的应用开辟了新的途径。EPR是一种很有前途的低温固体绝缘材料。

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.