Research to determine the acceptable emergency operating temperatures for extruded dielectric cables. Final report
- 1 November 1978
- report
- Published by Office of Scientific and Technical Information (OSTI)
Abstract
The maximum emergency operating temperatures of extruded dielectric cables were established several years ago and need re-evaluation vis-a-vis the materials and cable technology now available. A research program was undertaken with the objective of determining satisfactory limits of operation at elevated temperatures of extruded materials and cable constructions. This work focuses on the study of the temperature behavior of polymer materials used in conventional extruded cables. An extensive study has been made of the electrical, mechanical, thermal, and physico-chemical behavior of extruded dielectric materials as a function of temperature. Materials studied included XLPE, filled XLPE, EPR compounds and semiconducting XLPE, and data was obtained on specimens cut from full size extruded cables as well as laboratory molded specimens. Measurements of ac and impulse breakdown strength, ac loss and dielectric constant, dc resistivity, corona degradation; of mechanical properties such as tensile and compressive creep, bearing strength, hardness, thermal conductivity and thermal expansion; and of various physio-chemical properties, were performed over a range of temperatures extending from 25/sup 0/C to well above the present emergency operating temperatures. The results are presented in a form that emphasizes differences and similarities between the behavior of XLPE and EPR materials at elevated temperatures. The usemore » of those materials at elevated temperatures is discussed with regard to satisfactory cable operation under emergency conditions. « lessKeywords
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