GB173134A - Improvements in and relating to systems of electric power transmission - Google Patents

Abstract

173,134. British Thomson - Houston Co., Ltd., (General Electric Co.). Nov. 9, 1920. Regulation, automatic systems and apparatus for.-In an alternating-current supply system comprising a number of feeder circuits, a voltage modifying means is placed in each feeder circuit and is operated by current flowing between the feeder circuits to maintain a constant potential at a predetermined point in the system. In each of the feeder circuits 5, 6 connecting the supply mains 3 and the distribution mains 4 is placed a voltage regulator 10 operated by a reversible motor 12. The direction of rotation of the motor 12 is controlled by a relay 22, the coil 26 of which is in the secondary circuit of a potential transformer 27. The circuit of the coil 26 is provided with a line-drop compensator 37 comprising a resistance 39 and a reactance 40. Portions of the resistance 39 and the reactance 40 are connected in series with a similar resistance 41 and reactance 42, in the feeder circuit 6 in a circuit containing the secondary windings of transformers 43, 44. To maintain the circulating current between the feeder substantially zero, two cross-connected current-transformers 46, 47 are provided, the voltages in the secondary windings of which are normally balanced when the impedance drops in the feeder circuits 5, 6 are equal. A circuit containing the primary windings 48, 49 of transformers 50, 51 is connected across the secondary circuit of the transformers 46, 47. The secondary winding 52 of the transformer 50 is connected to a tap on the reactance 54 which is connected in the circuit of the coil 26. The secondary winding 53 of the transformer 51 is similarly connected to a reactance 55.