Patent GB-286601-A (GB)
Title: Improvements in and relating to carrie current supervisory systems
IPC: H02J13/00
Filed: 1928-02-25
Abstract: 286,601. British Thomson-Houston Co., Ltd., (Assignees of Farley, T. S., and Whitney, C. F.). March 5, 1927, [Convention date]. Selective distant control systems.-Relates to a system for selectively controlling and supervising apparatus units, such as circuit breakers, at a plurality of remote substations from a control station, by means of high-frequency current impulses transmitted over line wires which may also be employed for the transmission of power at commercial frequencies. Operation of any particular circuit breaker at a substation is effected by manipulating a corresponding impulse code transmitter at the control station that causes the interruption of the output circuit of a valve generator and thereby transmits a characteristic impulse code which operates a selector at the remote station to effect the desired operation. When the circuit breaker changes its position a supervisory lamp at the control station is selected and operated in a similar manner. Means are provided to prevent, when one transmitter is in operation, the operation of the other transmitters for a predetermined time period. Fig. 1 shows the apparatus at the control station, and Fig. 2 shows the equipment at one remote substation. Valve generator supply. The control and supervisory transmitters 1 at the stations comprise valve generators and amplifiers, the filaments of which are supplied through step-down transformers 25<1> by rotary converters 22, and the plate circuits are fed by direct current generators 23. Locking out transmitters at non-signalling stations. Assuming it is desired to operate a circuit breaker at a remote station, a master key 55 at the control station is operated to energize relay 42 which operates relay 24. Relay 24 switches the field winding and armature of the rotary converter across the supply 19, the armature being supplied at reduced voltage, and connects the direct current side of the rotary armature across the relay 25. The converter supplies the filament circuits of the transmitter 1, and as the speed increases the back electromotive force operates the relay 25, which switches full voltage across the armature and closes the field circuit of the generator 23. The relay 24 also energizes relay 31, which operates slow-acting relay 32 to close a series circuit for relays 36, 37 over contact 38 of relay 42. Upon energization of relay 42 slow-release relay 40 is energized so that operation of relay 36 closes the circuit of relay 8, which connects the transmitter 1 to line wire 3. Operation of the relay 8 also disconnects the receiver 9 from the line. The relay 36, however, deenergizes relay 40, which after an interval releases its aramature 43 to open the circuit of relav 8. In this manner an impulse of predetermined duration determined by the slow release of relav 40 is transmitted to the remote stations to operate the receivers 9 and the corresponding relays 12 which energize relays 14 to open the circuits of relays 31 and thereby prevent operation of the other transmitters. Furthermore the transmission of impulses is delayed for the predetermined period after initiation by the slow operation of relav 32 so that interference with a transmitting station is prevented. A locking-out signal is transmitted in a similar manner in the event of operation of the transmitter at a remote station by a circuit breaker. Operation of circuit breaker. Upon de-energization of relay 40 a green lamp 57, associated with the master key, is illuminated to signify that the apparatus is ready for the transmission of the selecting code of impulses which is sent as the result of the operation of the appropriate code wheel 58 to intermittently energize relay 8 over the back contact of relay 37. The relays 12 at all the remote stations respond to operate polechanging relays 15 which actuate selector switches A. B. The switch, which is responsive to the particular code transmitted, closes the circuit of the operating coil 59<1> of the appropriate circuit-breaker. When the code is completed relay 42 is de-energized and the apparatus is restored to normal. A red lamp associated with the master key is illuminated when the apparatus is in the normal condition. Signalling condition of circuit-breaker. When a circuit-breaker changes its position either automatically or under distant control, a contact such as 60 energizes a relay 61 which operates relays 40. 24. Relay 24 causes operation of transmitter 1 at the substation and energizes relay 31 which operates relay 32 to energize relays 36, 62 in series after a predetermined time period. Relay 36 operates in a manner similar to that at the control station to energize relay 8 for a predetermined time period and transmit an impulse to prevent operation of the transmitters at other stations. Relay 40 is de-energized to close the circuit of motor 63 over the back contact of relay 62. The motor operates contacts 64 to energize a relay 65 corresponding to the operated circuitbreaker and release the appropriate code wheel which operates the relay 8 to transmit the signal. At the control station a lamp 13 is flashed by the incoming signals and the selector 16 is operated by the pole-changing relay 15. The selector operates the relay 17, which rings a bell 18 and energizes the selected relay 20<1> over the contacts of the selector to illuminate the appropriate supervisory lamp such as 59. The operation of the bell 18 is maintained by relay 20, but may be nullified by depression of key 60<1>. Upon the completion of the code a contact 66 is opened by the code wheel to de-energize relay 65 and thereby restore the substation apparatus to its normal condition.