Patent GB-215321-A (GB)
Title: Improvements in or relating to the control of apparatus at an electric power sub-station from a central control office
IPC: H02J13/00
Filed: 1924-02-25
Abstract: 215,321. Automatic Telephone Manufacturing Co., Ltd., (Assignees of Richardson, R. G., and Bellamy, J. I.). April 30, 1923, [Convention date]. Selective distant control systems; tell-tale apparatus.-Relates to a system for the distant control and supervision of apparatus, such as the starter ST and circuit breaker CB of a motor generator MG, Fig. 5, at an 'automatic power substation, of the kind described in Specification 213,537, in which an operator at a control station after depressing a key K, Fig. 1, sends dialling impulses over two control conductors 16, 17 terminating at the substation in a switch E, Fig. 3, which is set to prepare the desired switching operation and energize a relay 306 of a signalsending relay set, such as SC-19, Fig. 4, individual to this switching operation. The relay 306, through the medium of a counting switch S and relay groups RG<1>, causes checking impulses to be sent over two signal conductors 18, 19 terminating at the control station in a switch D, Fig. 1, which effects the flashing of an " in " or " out " lamp L', L<2>, individual to the device under control. Having received this checking signal, the operator sends a final control impulse which causes the prepared operation to be carried out. When this takes place, a further checking signal is sent back to the control station, causing the flashing lamp to light steadily, and extinguishing the other lamp which indicated the condition of the device before the change was effected. The invention comprises the following improvements in such a system. Means are provided whereby the operator, after the transmission of the final control impulse, may await the receipt of the check signal indicating that the operation has been carried out, in which case the switches D, E are held in their set positions until this is received, or, if the device requires an appreciable time for its operation, he may release the key K immediately after sending the final control impulse, thereby causing the release of the switches D, E and freeing the checking apparatus. In the latter case, when the check signal ultimately comes through, since it may be due to the faulty operation of the switch D, or of the impulse-sending apparatus S, RG', in response to an automatic change in the condition of some device other than that which the operator desires to control, he checks it by dialling the signal number of the flashing lamp indication received. If the indication is correct, the flashing lamp lights steadily, but if the indication is wrong, the lamp continues flashing, the checking apparatus is released, and the signal is retransmitted. If, due to an incorrect operation, the switch D is set upon contacts the lamp of which is already steadily lighted, no checking signal is received but a warning buzzer B is operated. The operator then momentarily closes the control circuit, causing the checking apparatus to be released and the signal retransmitted as before. The arrangement and operation of the starter ST, circuit breakear CB, and motor generator MG at the substation are the same as in Specification 213,537. The switches D, E are two coordinate step-by-step switches of the well-known Strowger type. Since all the substation devices are controlled in a similar manner, the switching-in of the starter ST only will be described in detail. Closure of starter ST, Fig. 5, from the control station; preparation. The operator first presses a key K. Fig. 1, closing circuits for a slow-release relay 7 and a slow-to-act relay 6. The relay 7 closes a bridge across the control conductors 16, 17, and is shortly afterwards de-energized on the response of the relay 16, which places a further bridge across the conductors 16, 17. If the transmission of a signal from the substation is in progress at this time and has advanced to the point at which the release relay 27 of the signal switch D is energized, a circuit 39, 46, 15 is completed for the lower winding of a cut-off relay 5, which locks up over the key springs 4, cuts off the relays 6, 7, opens the control circuit at armature 9, and closes a circuit for a warning lamp L. Owing to the adjustment of the relays 6, 7, the lower winding of the relay 5 is not disconnected from the switch D at armature 15 until a sufficient interval has elapsed to permit any incoming signal to progress as far as the energization of the release relay 27. In all cases therefore when an incoming call has been started before the key K is closed, the control circuit is opened and the lamp L is lighted, so that the operator is warned to postpone his call until the incoming call is signalled. The - closure of the bridge across conductors 16, 17 energizes the line relay 201, Fig. 3, of the substation control switch E, and the subsequent response of the slow-release relay 202 closes a circuit over conductor 155 for a relay 108, Fig. 2, which grounds a holding wire 156 of the relay group RG, and disconnects battery from a pick-up conductor 164, thereby preventing the sending in of a signal by one of the relay sets SC-11, SC-12 &c. until after the operator has completed the present call. The operator now dials the number 19 to set the control switch E to the position in which the operation of the starter ST is prepared. The switch E operates in well-known manner, the first digit t raising the wipers 233, 234 to the first level, and the second digit rotating them to engage the ninth contact set 239, 240 in this level. During this rotary movement the slow-release relay 204 is energized and closes a circuit 153, 220, 252, 157, 127 for the upper winding of a discriminating relay 103, Fig. 2, which locks up over the grounded. wire 156, and opens the circuit of the lower winding of a relay 102. Transmission of check signal to control station. At the end of the rotary movement of the switch E, the slow relay 204 relapses and completes a circuit 214, 218, 234, 248, 163, for the switching relay 205 and for the left-hand winding of a relay 306, Fig. 4, of the appropriate signal-sending relay set SC-19. The relay 205 locks up and directly earths the switch wiper 234, whilst the relay 306 grounds the starting wire 158 and energizes a relay 107, Fig. 2. The relay group RG<1> and the counting switch S now operate in the manner described in Specification 213,537 to send over the signal conductors 18, 19, two series of impulses corresponding to the setting of the switch E. These impulses are received by the line relay 26 of the control station signalling switch D, the wipers 53, 54 of which are set in known manner upon the ninth set of bank contacts 57, 58 in the first level. Upon the termination of the rotary motion, the slow relay 29 de-energizes and completes a flashing circuit F, 38, 42, 30, 53 for theappropriate " in " lamp L', which informs the operator of the position of the control switch E. The switching relay 30 is energized in this circuit, locks up, and prepares a circuit for a change-overrelay 31. Completion of prepared switching operation. Assuming that the operator has received the correct check signal, he now dials a further digit 1. If he desires to await an indication that starter ST has operated, he holds the key K depressed, but if he does not wish to hold the switches D, E operated during the actuation of the starter, which may take some time, he dials the last impulse and immediately releases the key K. In either case a single impulse is thereby sent over the relays 201, 204, 206, Fig. 3, the wiper 233 is grounded, and an impulse is delivered to a relay 425, Fig. 5, which locks up and initiates the operation of the starter switch ST. The starter ST is thrown in in two stages as described in the previously-mentioned Specification. Signalling operation of starter ST if key K is held depressed. As a result of the starter ST being thrown into running position, the lever 417 is moved to the left and transfers ground from the conductors 312 to the conductors 311, thereby deenergizing the cut-off relay 307, Fig. 4, of the appropriate " out " signal-sending relay set SC-10, and closing a circuit 311, 382, 383, 157, 128, 102 for the right-hand winding of the already-energized relay 306 of the " in " signal-sending relay set SC-19. The relay 102, Fig. 2, locks up to the grounded wire 156, opens the circuit of the signal switch line relay 26 at armature 114, and closes a circuit for a slow-to-act relay 101, which after a short interval grounds a cut-off conductor 160, and at armature 110 again closes the line circuit of the relay 26. In this manner a momentary impulse is sent over relays 26, 29, 31, the relay 31 knocking up, disconnecting the wiper 53 and thereby opening the flashing circuit of the lamp L<1>, and grounding the other wiper 54 over which the right-hand winding of a polarized magnet 60 is energized. The armature of this magnet 60 is now tilted to the right, opens the circuit of the " out " lamp L<2> and closes a direct current circuit for the " in " lamp L<1>. Release of switches D, E and relay groups RG, RG<1>. The grounding of the cut-off conductor 160 by the relay 101 closes a circuit for the cut-off relay 305, Fig. 4, which locks itself to the grounded conductor 311, and opens the circuits of both windings of the relay 306. Relay 306 removes earth from the starting wire 158, and the signal-sending relay group RG' is restored as described' in Specification 213,537. The disconnection of the conductor 158 also opens the circuit of relay 107, Fig. 2, which relapses but leaves the holding wire 156 grounded at armature 131 of relay 108. After an interval sufficient to permit the magnet 60, Fig. 1, to be operated, the circuit of the line relay 26 is opened at the relay group RG<1>, and upon the relapse of the slow-release relay 27 a circuit is closed for the release magnet 33. The switch D now restores and the wiper 54 is disconnected, but the armature of the signal magnet 60 is held tilted to th