Dielectrics for superconducting systems

Technical and economic considerations indicate that it is advantageous to operate cryogenic underground cables at high voltages in an optimum range between approximately 100 and 500 kV. Several programs under way in the United states for the development of high voltage superconducting or cryoresistive cables were recently summarized by Belanger.
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An appendix to his paper summarizes the most important work in progress in other countries. In particular, the U. S. Atomic Energy Commission has funded a program to investigate several different superconducting cable concepts. The design of these high voltage cryogenic cables will require engineering data on the dielectric behavior of cryogenic liquids and solid insulators similar to that which already exists for room temperature liquid and solid insulation.