Super electrical insulation of polymers in cryogenic region

When superconducting power apparatuses and electronic devices are commercially available in the near future, polymers will play a decisive role in the design of electrical insulation. The working temperatures of superconductors regardless of low temperature superconductors at liquid helium temperatures or high temperature superconductors at liquid nitrogen temperature are in the cryogenic region. The polymer insulation at any temperature has a particular role which can not be expected from the gaseous or liquid insulation, namely to support mechanically current carrying conductors. The failure of power apparatuses and electronic devices occur in an insulation part which sustains electric field rather than a conductor part which carries electric current. The performance of the polymer insulation supporting conductors at high potential, therefore, determines the life of every apparatus and device. The capability of electrical insulation of polymers at cryogenic region is generally excellent and it can be named "electrical super insulation" from the criteria of electrical insulation designers at room temperature or above. These aspects will be reviewed in this paper.