Patent GB-234111-A (GB)
Title: Improvements relating to electrical control systems
IPC: H04Q9/04
Filed: 1925-05-13
Abstract: 234,111. Metropolitan-Vickers Electrical Co., Ltd., (Assignees of Wensley, R. J., and White, T. U.). May 15, 1924, [Convention date]. Tell-tale apparatus.-In a control system wherein the apparatus at a substation is controlled from a central station, means are provided whereby the operator at the central station may obtain indications of the voltage, current, power, &c. at the substation. Figs. 1 to 4 show the central station, and Figs. 5 to 10 the apparatus at the substation. The central station is provided with a key K for. operating each unit, e.g. a circuit breaker C, Fig. 10, at the substation and one or more groups of keys K<1> - - K<10> corresponding to the various indications to be obtained. Each group of relays 300 - - - 309 associated with these keys can be connected by a switching relay, such as 310, to the contacts of a single group of counting relays, 101 - - - 124 common to the several groups of keys K<1> - - - K<10>. A synchronoscope 253 and meters 254, 255, 256 are selectively connected by the corresponding relays in the group- 300 - - - 309 to lines 41, 42 leading to the substation where they may be extended selectively by corresponding relays in the group 500 - - - 509 to voltage indicating apparatus, Fig. 8, current and power indicating apparatus, Fig. 9, or to a synchronizing transformer, Fig. 10. When a meter reading is desired, the appropriate key in one or other of the groups of keys K<1> - - - K<10> is operated, and a " start " key K<11> is operated to initiate the operation of controlling apparatus which actuates the counting relays 101 - - - 124, 700 - - - 723 synchronously. The selective control of these relays is effected over the line 40 by pairs of relays 413, 614 and 410, 617, Figs. 4 and 6, which are connected alternately to the line. The counting relays operate the selecting relay chains at both stations in sequence until the relays corresponding to the operated key are reached. If the operated key is not in the first group the first group of selecting relays will be operated without effect, and then the second and following groups will be operated by the counting relays until the relays corresponding to the operated key are reached. When these relays are operated, the lines 41, 42 are automatically taken into use for transmitting meter indications or for operating apparatus units at the substation and obtaining corresponding supervisory signals. Unless the selecting relays operate in the proper sequence. under the control of the counting relays, the pairs of relays 413, 614 and 410, 617 are not energized alternately and the operation of the control circuit is interrupted. Signalling voltage on a phase. In order to ascertain the voltage across one phase 890, Fig. 8, the relay 815 must be selected. This is accomplished by operating the appropriate key K<10> to open its contacts and the " start " key K<11>. Normally, the circuit of the relays 210, Fig. 2, and 801, Fig. 8, is completed over the trunk line 40. The relay 210 energizes the relay 209 and prepares the circuit of the starting relay 206. When the key K11 is depressed, the relay 206, prepares the circuit of the relay 207 but the latter is not energized since it is shortcircuited by the key K<11>. As soon as the key is released the relay 207 is energized and the circuit of the relays 210, 801 is opened. When the relay 210 is de-energized, the relay 203 is energized to (1) switch the line relay 413 on to the trunk line 40, and (2) energize the relay 211 and consequently the relay 310 to connect the selecting relays 300 - - 309 to the counting relays 101 - - 124. At the substation, the relay 801 is de-energized and the relay 800 is energized to connect the line relay 614 in series with relay 413 and associate the counting relays 700 - - 723 with the selecting relays 500 - - 509. The line relays 413, 614 are thus energized. The relay 413 energizes the relay 403 which causes the operation of the relay 408 and completes a circuit to the counting relay 112. The relay 112 prepares the relay 111 which operates, due to the removal of the short-circuit caused by the energizing circuit of the relay 112, when the line circuit is opened at armature 438 of the relay 408. The counting relay 111 energizes the selecting relay 309 to (1) light a signalling lamp 327, (2) prepare a signalling circuit over the line 41, and (3) prepare the circuit of the relay 417. The circuit of the relay 417 is, at this time, open at the contacts of the key K<10> and in consequence the circuit of the relay 408 cannot be opened to restore the line circuit until the key is released.. A signalling-lamp is associated with each selecting relay at the control station. Similarly at ther substation, the control circuit operates the select. ing relay 500 which completes the circuit of therelay 815, prepares a circuit over the line 41 and operates a relay to prepare the circuit of a second line relay 617. The circuit of the relay 815 includes a slow-to-act relay 565 and after a short interval the relay 815 connects thesecondary of a transformer 890. to a metering device consisting of a Kelvin balance 818. According to the voltage of the phase 890, a motor 835 is rotated in one or other direction to vary a resistance 833, which is now included in the line 41, and cause a corresponding deflection of a. voltmeter 255 at the control station. A galvanometer 832 is included in the line and actsto restore the balance 818 to its normal position during the signalling operation. During thesignalling operation the control circuit over the line 40 is maintained open by the relay 408 at the control station. In order to ascertain the voltage across another phase, the operator actuates the key K<9> and restores the key K<10>. When the key K 10 is restored the relay 417 is operated and in consequence the relay 409 is energized and the relay 408 is de-energized to complete the control circuit over the line 40 and the second pair of line relays 410, 617. The relay 410 operates in a similar manner to the line relay 413 to energize the counting relay 124 and disconnect the selecting relay 309. The relay 408 then operates to open the control circuit. This has the effect of de-energizing the line relay 410 to allow the counting relay 123, the circuit of which has been prepared by the relay 124, to prepare the circuit of the counting relay 110 and operate the selecting relay 308. At the substation, the operation of the line relay 617 causes the selecting relay 500 to disconnect the transformer 890 from the balance 818 and the line circuit to be broken at armature 619. The relay 617 is thus. de-energized to permit the counting relay 713 to. close the selecting relay 501 and prepare thecircuit of the next counting relay 702. Operation of the relay 501 prepares the circuit of theline relay 614 and causes relay 816 to connect the transformer 821 to the balance 818. The balance operates in a manner similar to that described' above and the voltmeter 255 gives an indication of the voltage across the selected phase 890. If it is desired to ascertain the resultant voltage on the three phases 890, the operator actuates the key K<8> and restores the key K<9>. The key k<9> operates the relay 416 and thereby causes the control circuit to select the relay 817 through the contacts of the selecting relay 502.. The relay connects the transformer 824 to the metering device and the signalling circuit is closed and an indication of the resultant. voltage is given on the voltmeter 255. Signalling current in a phase. This is accom- ,plished by operating the key K<7> to bring about the energization of the relays 306, 503 at the -control station and substation respectively. At the substation, the circuit of a relay 900, Fig. 9, ,is completed to connect a current transformer 912 to the metering device 906 and cause the variation of the resistance 942. This produces an indication on the ammeter 256 at the control station. In a similar manner, the current in another phase may be indicated by the ammeter 256 by the operation of the appropriate selecting key. Signalling current and voltage simultaneously. This is accomplished by operating the key K5 to select the relays 902, 903, Fig. 9, and cause both transmitters 833, 942 to transmit over the signalling lines 41, 42 and thereby operate the ammeter 256 and voltmeter 255. Signalling power of the phases. The wattmeter 254 at the central station is connected to the phases 890 when the relays 904, 905 are selected by operation of the key K<4>. Signalling synchronism of machines G, G<1>, Fig. 10. In order to ascertain when the machines are generating in phase, the key K<3> is operated to select the relays 302, 507. These relays connect the windings 1008, 1009, Fig. 10, of the transformer 1015 which is associated with the machines, through the trunk conductors 41, 42 to the synchronoscope 253 at the control station. Parallelling the machines G, G<1>. 'When the two voltages are in synchronism the key K<3> is released and the control circuit functions to energize the selecting relays 301, 508. A circuit is established from the control key K, lines 270, 41, 595 to the relay 1002, which energizes a closing coil 1003 of a circuit breaker C to connect two feeders 1020, 1021 together. The circuit breaker also energizes the relay 1000 to prepare the opening coil relay 1001, and complete a circuit over lines 596, 42, 272 to relay 239. The operation of the relay 239 causes (1) the extinction of supervisory lamp 247 and the illumination of the lamp 246, (2) the initiation of the control circuit and the selection of the relays 300, 509 which in the apparatus illustrated are not associated with an apparatus unit or metering device. A key K is provided for each apparatus unit and is associated with a corresponding selecting relay. Associating subsequent groups of selecting relays with the counting relays. When at length the last