Patent GB-190902147-A (GB)
Title: Improvements in Electric Accumulator Substations Fed from Alternating Current Systems.
Inventor: TAYLOR ALFRED MILLS
IPC: H02J3/32
Filed: 1909-01-29
Granted: 1910-03-29
Abstract: 2147. Taylor, A. M. Jan. 29. [Cognate Applications 2335 and 5623.] Systems for conversion employing rotary converters &c.-The sub-station of an alternating-current distribution system is provided with a rotary-converter unit arranged for the lagging effect due to inductive loads, a second rotary unit to compensate for the reactance of the line itself, and one or more rotary units arranged to compensate for the momentary variations of the load. Each of the rotary units is connected to a battery as described in Specification No. 22,581, A.D. 1907, or they may all be connected to one battery, while during the peak of the load all the units may be arranged in parallel two relieve the main generator. The high-tension lines A, Fig. 1, are connected to the distributionfeeders D and sub-station bus-bars E through a step-down transformer B. The rotary converter a<1>, arranged to compensate for inductive loads, is connected on the alternating- current side to the bus-bars E through a transformer c<1>, and on the direct-current side to a battery b'. The field g<1> of the converter a<1> is fed from an excitor j<1>, the field k<1> of which is controlled by a regulator o', the current coil m<1> of which is fed from a transformer p and a voltage coil n<1> fed from the transformer @r. The ratio of the transformer p may be varied by a switch q. To compensate for the reactance of the distributing line D, the field g<2> of a rotary converter a<2> is fed from an exciter j<2>, the field k<2> of which is controlled by a regulator o<2> having a potential coil m<2> fed by the transformer r, and a current coil n<2> fed by the transformer s. The load on the main generator is equalized, during momentary variations, by means of rotary converters a', a<4> connected to batteries b<3>, b<4>; while their fields g<3>, y<4> are fed by exciters j<3>, j<4>, the fields of which are controlled by a regulator o<3> having a potential coil m<3> and a current coil n<3>. When the variations of load are gradual, the regulators may be replaced by indicators, the machines being handcontrolled by means of the regulators h', h<2>, h<3>, h<4>. The rotary converters may be replaced by motor converters, induction motor generators, or synchronous motor generators, but in all cases the machines connected to the batteries b<1>, b<2> must be of the synchronous type. In the arrangement shown in Fig. 5 when a large converting unit is employed with a set of batteries b', b<1>, one pole of the battery is connected to one brush of the machine a<1> while the other pole is connected to the neutral point of the transformer c<1>, and when a second set of batteries b<1> b<1>, b' b<1> is added, the free end of the set is connected to the second brush of the machine. To compensate for the reactance in the incoming or outgoing lines, transformers H, J, Fig. 6, are inserted in series in the leads C, the secondaries of these transformers being connected to a rotary converter a<3> by means of a switch S. The transformers may be short-circuited by switches L. Current transformers O are inserted in the outgoing lines D, and are arranged to be connected to the converter a' by means of a double-pole switch Q, while a second switch R is arranged to connect the converter a' to its transformer c<1>. The primary winding of a transformer K, placed in parallel with the primary windings of the transformers H, J has its secondary winding in series with the secondary winding of a transformer G, the primary winding of which is in parallel with a choking-coil F in the high-tension line A. The winding m<3> of the regulator o<3> is supplied by these two transformers, the regulator operating upon the field of the exciter j<3> to energize the field winding g<3> of the converter a<3>, which compensates for the reactance of the incoming line. The reactance of the outgoing line D is compensated for by means of a similar arrangement of transformers P, N which control the excitation of the converter a<1>.