Patent GB-417795-A (GB)
Title: Improvements in or relating to electrical power metering systems
IPC: G08C19/18
Filed: 1933-04-12
Abstract: 417,795. Distant-control and signalling systems. WESTINGHOUSE ELECTRIC & MANUFACTURING CO., East Pittsburg, U.S.A.-(Assignees of Stoddard, R. N. ; 6744, Penn Avenue, Pittsburg, U.S.A.) April 12, 1933, No. 10978. Convention date, April 15, 1932. [Class 40 (i).] In a system for signalling the readings of an integrating meter, the meter impulses an oscillation generator so as to transmit impulses which are totalized at the receiver. The frequency of oscillation may also be varied by a second meter so as to produce indications of instantaneous values of the quantity to be measured. As shown in Figs. 1 and 2 the indications of meters 16 are recorded on meters 35 at the main station. Each meter 16 is associated with an oscillation generator 10 tuned to a characteristic frequency and is adapted to impulse a relay 19 controlling the grid circuit of the generator in accordance with the indications of the meter. In this manner, each meter transmits impulses of characteristic frequency over the line wires 22 to the main station wherein tuned circuits 28 sort out the impulses for delivery to the appropriate totalizing meters 35. The valve circuits at the transmitting and receiving stations are supplied by full wave rectifiers 14. The oscillation generators 10 at the substations may also include a variable condenser operated directly by an indicating instrument and adapted to vary the frequency within a predetermined range in order to transmit instantaneous values. The corresponding receiver has a tuned circuit which is responsive to the frequency band and is connected to a frequency meter adapted to indicate the instantaneous value, and also the recording instrument which is responsive to impulses generated by an instrument, such as 16. The signalling impulses may be transmitted over telephone circuits having the usual repeaters, loading coils &c. The Specification as open to inspection under Sect. 91 describes a system of supervisory control. Figs. 6 and 7 (Cancelled) show the equipment at the control station and two substations connected over line wires 22. The control station and substations are provided with oscillation generators 101, 102 and tuned receivers 107, 108. The transmitting and receiving equipments are associated with the line wires through contacts of transfer relays To, Ts which are controlled by switching relays e.g. 203, 403 according to whether a station is transmitting or receiving. Relay chains, e.g. 201 .. 204, 401 .. 404 are associated with the frequency generators in such a manner that when the battery is applied to leads such as 239, 438 in response to the functioning of control station or substation apparatus,the relays operate in cyclic order to cause impulsing of associated relays, e.g. 200, 400 to transmit impulses of characteristic frequency over the line wires. The impulses, which persist as long as battery is applied, are received by the corresponding tuned receiver 107, 108 and operate the appropriate relay 200, 400. The Specification also describes systems for indicating synchronism and for the protection of power lines against faults. In the former system, the supplies to be synchronized are associated through synchronizing transformers with a valve oscillator connected to frequency responsive means at a remote station arranged to operate a synchronism indicator. In the protection system the ends of a section of power line are provided with circuit breakers having associated therewith valve oscillators of different frequencies and receivers tuned to the beat of the different frequencies. The oscillators are normally maintained in operation by power relays energized from each end of the line and the beat frequency produced causes operation of both receivers to maintain both circuit breakers closed. In the event of a fault one or other power relay is released and the corresponding generator is rendered inoperative. The beat frequency receivers are therefore released and the circuit breakers are tripped. The circuit breakers may be reclosed by manually operated switches arranged in parallel with the power relays and adapted to initiate operation of the oscillation generators. This subject-matter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to Specification 274,484, [Class 40 (i).]