Insulation Design of Self Contained Oil-Filled Cables for D.C. Operation

Results of studies on the effect of different insulation constructions and loading conditions on the design of self-contained oil-filled cable are given. It is shown that insulation performance and current loading are interrelated and that performance of the cable under transient voltage conditions can be improvment by adopting an insulation made up of different density papers-allowance being made for the differing thermal and electrical properties of these papers. However full benefit of this construction is not necessarily achiev able because of possible limitations on long time d.c. strength of some of the grades and thicknesses of paper.