Patent GB-282858-A (GB)
Title: Improvements relating to electrical remote control systems
IPC: H02J13/00
Filed: 1926-09-24
Abstract: 282,858. General Electric Co., Ltd., and Smart, N. C. Sept. 24, 1926. Selective distant control systems; tell-tale apparatus.-In a system for controlling and supervising the operation of apparatus at a remote station in which after a selective operation, checking signals depending upon the selection are transmitted back to the control point, means are provided for automatically restarting the selective operations if the checking signals indicate that an incorrect selection has been made. The operation is repeated until a correct indication is given when further means are operated to automatically operate the selected apparatus. Figs. 1 and 2 show the apparatus at the control station and Figs. 3 and 4 show the substation equipment. Circuit breakers such as 21, Fig. 4, are controlled by coresponding selecting keys, such as 3, Fig. 1, any one of which when operated marks in a characteristic manner a step-by-step switch CS which controls the transmission of impulses over the line wires 1, 2. Instead of the line 2 an earth return may be utilized. The impulses operate a switch SC at the substation and thereby select the circuit corresponding to the operated key. Prior to closing the selected circuit, the answer back signal checking the selection is transmitted to the control station. The selecting switch SC marks the switch SI and initiates the transmission of a characteristic impulse code which operates the switch IS at the control station. If the selection is correctly performed the switches IS, CS occupy complementary positions and a further impulse is transmitted to perform the operation. Supervisory signal lamps, such as 4, 5, are operated over the contacts of the switch IS to indicate the nature of the operation. Should, however, the switches IS', CS not be in agreement due to a faulty selecting operation stepping continues and correcting means are operated to bring all four switches into synchronism and into positions corresponding to the required setting. Operation of the appropriate apparatus is then effected automatically. The arrangement is such that the switches do not restore to a normal setting when a selection has been completely performed. Selection of circuit breaker. The appropriate key 3 is operated to energize a relay 54 over line key contacts and contacts of a normally energized relay 51. The relay 54 energizes the stepping magnet 59 of the switch CS and the relay 57. The relay 57 closes the line circuit from battery at the control station over the upper windings of the line relays 56, 502. Each of these relays is differentially wound so that when both windings are energized the relay remains inoperative but when one or other winding is energized the relay pulls up. The relay 57 also closes a local circuit over the winding 63 of the line relay 56 so that this relay remains inoperative. The substation relay 502, however, has current flowing in winding 501 only so that it is operated to energize relay 506 and stepping magnet 507 of switch SC. The relay 506 opens a short circuit across the winding 503 of relay 502 at the contact 603 and connects battery in a local circuit to energize winding 503. This battery also opposes battery at the control station so that the current in windings 63, 501 of the line relays ceases thereby causing the operation of the line relay 56, the relay 502 remaining energized in its local circuit. The line relay 56 de-energizes the relay 57 and the driving magnet 59 and in consequence the switch CS moves one step forward. Upon deenergization of the relay 57, the winding 63 is short circuited and relay 56 remains energized over this line circuit, the current in the line causing the energization of winding 501 of relay 502 and in consequence the release of relay 502 which opens the circuit of the driving magnet 507 and thereby allows the switch SC to moveone step forward. The relay 506 is also de-energized to permit the release of the line relay 56 at the control station. When the relay 56 releases, the relay 57 and the drive magnet 59 are again energized. Relay 57 causes the operation of line relay 502 which again operates relay 506 and drive magnet 507. Relay 506 energizes line relay 55 which releases relay 57 and causes the switch to move forward through a further step. Deenergization of relay 57 releases relay 502 to permit the switch SC to move forward another step and the relay 506 to release and thereby release the relay 56 to start another similar cycle of operations. The interaction of the line relays thus causes the alternate operation of the switches CS, SC into corresponding positions, the stepping operation at each station being dependent on the reception of an impulse from the other station, indicating that the required step in the cycle of operations has been correctly performed. Operation of the key 3 marks the contact 111 in the bank 69 of the switch CS and when during stepping the wiper 65 makes contact therewith the circuit of a relay 50, which stops the stepping of switches CS, SC, is completed. The relay 50 opens the circuits of the relay 57 and drive magnet 59 so that line impulsing ceases and the switches remain in their selective, positions. Checking signal. In order to ensure that faulty stepping does not result in incorrect selection, the position of the switch &c. is signalled back to the control station prior to operation of the selected unit. Upon release of a relay 508, which has been maintained energized during impulsing, a relay 519 is operated to mark a contact in the bank of contact 523 of switch SI over the wiper 512 of switch 56 and operate a relay 505 which energizes the relay 506 and the driving magnet 529 of the switch SI. The relay 506 re-starts a cycle of impulsing operations similar to that previously described and the switches SI, IS are operated until the switch SI reaches the marked contact and a relay 504 is energized to open at the contact 604 the circuits of the drive magnets 529 and the relay 506 to prevent further impulsing. When impulsing ceases relays 68 and 508 at the control station and substation respectively are released to cause the operation of relays 73, 530. Operation of selected unit and supervising signalling. Assuming that the operation has been performed correctly and all the switches rest upon corresponding contacts, a circuit is then closed over the wiper 82 of switch IS, wiper 67 of switch CS, relay 74, contact of relay 73, line 1, operated contact of relay 530 to relay 531. Relays 74, 531 operate. At the substation the relays 531, closes at the contact 619, the selected circuit over the wiper 511. One or other of the relays 22, 23 is thus energized to operate the associated circuit breaker. The relay 74 at the control station operates a relay 12 over the wiper 80 to remove the marking on the switch CS and reverse the indications of the supervisory lamps 4. 5. The operating circuit of the circuit breaker is maintained for a period sufficient to allow operation by the action of the vibrating relay 76 at the control staion. The relay 73 is held energized to maintain the line circuit by a relay 88 operated by a contact 56 which vibrates upon de-energization of the relay 76 when impulsing ceases. Synchronizing arrangements.-If due to faulty stepping the switches do not occupy similar settings at the termination of impulsing, relays 74, 531 do not operate and relays 73, 530 together with the other operated relays release. Since, however, the key 3 is still operated, the switches continue to step until synchronizing means are operated to bring the switches into their correct relationship. One position on each switch is allocated as a synchronizing position and the arrangement is such that the switches are brought into step on these contacts. The switches CS, SC, IS, SI are provided with synchronizing banks of contacts 70, 516, 84, 524 and synchronizing contacts 132, 633, 133, 634. Assuming the switch CS in advance of the switch SC, stepping continues until the wiper 66 engages the contact 135 and thereby energizes relay 89. When the wiper 66 engages the next contact, relay 58 is operated to open the circuit of the stepping magnet 59. Impulsing continues, but the switch CS rests. on the synchronizing contact. The switch SC continues to step until wiper 513 engages the contact 633 when a relay 518 is energized to disconnect the line relay 502 from the line and thus' prevent further impulsing and also close the circuit over the line 1 for relay 56 which releases relay 68 and therefore relay 58 to restore the driving circuit of magnet 59. Since at the sub-station relay 502 is disconnected from the line, relay 508 releases'. This causes the reconnection of relay 502 to line 1 and the normal cycle of impulsing is continued, the switches CS and SC now being in step. The operation of bringing the switches SI, IS into step is similar. Signalling automatic change of circuit breaker. When the circuit breaker 21 is moved into its " closed " position, the relay 536, is operated over a wiper 525 of switch SI and locked. When the breaker trips out a circuit is established for relay 505 over the contacts 24 and operates contacts of relay 536. The relay 505 operates relay 506 and energizes the drive magnet 529 and impulsing is initiated to drive the switches SI, IS. The contact 25 on the circuit breaker marks the appropriate contact on the bank 523 of switch SI so that when the wiper 526 engages therewith relay 504 is energized. Relay 504 opens the driving circuit and prevents further impulsing. Upon the cessation of impulsing relay 68 releases and causes the operation of relay 72 which closes a circuit over wiper 80 of switch IS for unlatching winding 10 of relay 12 which releases and changes the lamp indications. A circuit for the pilot lamp 16 and alarm bell 20 is also closed and maintained by the relay 72 until the attendant throws the key 3 into a position corresponding with that