A NOVEL ELECTROMAGNETIC-FIELD SHAPER FOR PIPE-TYPE CABLE SYSTEMS

A novel electromagnetic field shaper designed to reduce the electrical losses and increase the current carrying capacity of pipe-type cable systems was conceived in 1983. Theoretical development of the field shaper and possible manufacturing technique were carried out between 1983 and 1987. A United States patent for this field shaper was issued on January 27,1987 and a Canadian patent application is pending. The salient feature of this field shaper is that in addition to significantly reducing the eddy current losses in the pipe or cables enclosure, it also reduces the losses in the cables due to their proximity to the metallic enclosure. The field shaper effectively minimizes the ratio of the ac over the dc resistance of the cables, and consequently maximizes the ampacity of the system, at a relatively low increase in the initial cost of the system. This paper introduces the concept ofthe electromagnetic field shaper and presents a general analysis ofthe loss reduction mechanisms associated with its design features and parameters. © 1989 IEEE