GB179824A - Improvements in electrical distribution in alternating current systems - Google Patents

Abstract

179,824. Taylor, A. M. Feb. 7, 1921. Polyphase systems.- A single-phase or a polyphase current is superposed upon the currents of existing three-phase cables by employing transformers having a broken-up delta winding, a broken tee winding or a broken open delta winding. The current from an auxiliary generator AG, Fig. 1, is superposed upon the currents of existing three - phase cables 3PC by connecting the generator AG to the mid-points of the secondary windings S<1>, S<2>, S<3> of a transformer SUT. The superposed current is taken from the mid-points of the primary windings P<1>, P<2>, P' of the transformer SDT and transformed by a transformer TTT. In the arrangement shown in Fig. 2, a two-phase auxiliary generator AG is connected to the three-core cables 3PC through the secondary windings E of a three-phase twophase transformer. The sections of the cable sheathings CS or LS are connected by resistances RR to equalize the potentials on the sections. In a modification, four conductors of the two threephase cables are employed to supply the energy and the remaining two conductors are utilized as returns for the superposed current. Three single-phase transformers are employed and two are connected in parallel on the overloaded side. A further modification is described in which a two-phase current is superposed and a two-phase three-phase transformer is employed at the receiving end. Specifications 151,294 and 158,008 are referred to.