GB1021274A - Arrangements for attenuating high-frequency electric currents in heavy electric current transmission lines - Google Patents

Abstract

1,021,274. Conductor arrangements. SIEMENS & HALSKE A.G. April 18, 1963 [April 19, 1962], No. 15256/63. Heading H2H. [Also in Division H1] A choke for attenuating high frequencies in a plurality of pairs of heavy current-carrying conductors is formed by passing at least one conductor of each pair through a common ferromagnetic sleeve la, 1b, 1c, the vector sum of the currents flowing in the conductors in the sleeve being substantially zero. This avoids the reduction in effective permeability which would occur upon saturation of the sleeve by a unidirectional current; and hence a sleeve (e.g. of ferrite) having a high initial permeability of 100 or more may be used. The sleeve may comprise one or more tube or disc sections arranged end to end, and having permeabilities which decrease in order to remove resonance points in distributed L-C chains. The sleeve with its tubular surround 4 (Fig. 7) may be anchored by a conductive bracket 2 (Fig. 2, not shown), which acts as a by-pass capacitor, and the sleeve may have a radial slot (Fig. 8, not shown) closable with a ferromagnetic key piece to allow insertion of conductors without disconnecting them. To reduce stray magnetic fields produced by the choke, the conductors may be twisted (Fig. 7) and each conductor may be split into a pair of lines, each pair being placed symmetrically in the sheath (Figs. 5, 6, not shown).