Patent ID: 6506971
Filing Date: 2003-01-14
Classification: H01B

Abstract:
A method of designing a single-phase electric cable comprising insulated conductors for conducting currents in different directions, each conductor having a design cross-section area and given current to pass therethrough, said cable providing a predetermined minimal strength of the external magnetic field by ensuring a predetermined degree of attenuation defined in comparison to the external magnetic field of a conventional cable carrying the same current, the method comprising the following steps:(a) assembling at least one of said conductors from a plurality of n subconductors to be connected in parallel, wherein the sum of cross-sectional areas of the subconductors is equal to the design cross-section area of said at least one conductor; (b) arranging said conductors and said subconductors in the cable in such a manner that each of said subconductors is adjacent to at least one of said conductors or said subconductors carrying current of opposite direction; (c) placing all said conductors and said subconductors as close as possible to one another; (d) arranging magnetic dipoles from currents passing via all said sub-conductors and conductors, determining value and direction of magnetic moment of each of said magnetic dipoles, and adjusting the arrangement of said conductors and sub-conductors in such a manner that the sum of the magnetic moments is: &Sum;i=1N&it;â€ƒ&it;Mi=0where N is the total number of said magnetic dipoles; (e) estimating the external magnetic field and adjusting the degree of attenuation thereof by selecting the number n of subconductors for assembling said at least one conductor.