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

研究人员一直在研究高分子材料（乙丙橡胶）在超导电力设备电绝缘系统中的应用。在低温下，对液氮或液氦等流体的实用绝缘研究很多，但对高压设计的固体绝缘研究很少。结果表明：(1)在EPR的情况下，添加填料的塑料具有优异的电性能，并且在低温下热收缩可控。(2)直流电气绝缘系统用填料EPR试样的击穿和空间电荷表明，低温击穿强度远高于室温。这可能是由于电极的损耗载流子注入，这对超导电力设备的电绝缘设计具有强烈的激励作用。(3) EPR在低温和室温下的抗树性以及填料对其抗树性的影响表明，EPR在低温下具有足够的抗交流电采伐性，填料对其抗交流电采伐性略有提高。本研究结果为高分子材料在超导电力设备电绝缘系统中的应用开辟了一条新途径。EPR是一种极有前途的低温地区固体绝缘材料。

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.