Patent GB-214599-A (GB)
Title: Improvements relating to electrical control systems
IPC: H02J13/00
Filed: 1924-03-29
Abstract: 214,599. Metropolitan-Vickers Electrical Co., Ltd., (Assignees of Wensley, R. J.). April 16, 1923, [Convention date]. ,Selective distant-control systems; tell-tale apparatus.-In a system for supervising and controlling from a remote point the operation and condition of.a a number of apparatus units at each of a number of sub-stations, the automatic transmission of the supervision signals to the control office, Fig. 1, is effected by means of a 25-point finder-switch F, Fig. 2, which hunts for any apparatus unit which changes its condition, and by a code-sending switch CD which moves from its normal position in two stages to contacts marked by the setting of the finder F and in so moving transmits two corresponding sets of impulses over trunk conductors 191, 192. Each substation, Figs. 2 .. 4, is connected to the control station over a three-wire trunk 190 .. 192, associated with each end of which is a two-coordinate connector switch of the Strowger type as employed in .automatic telephony, the connector H' at the substation end being set by impulses transmitted from the control station over the trunk conductors 190, 191, to effect any desired control of the substation apparatus, whilst the connector H at the control station is set by the impulses transmitted over the conductors 191, 192 by the switch CD, and indicates the change in the substation conditions on the supervisory lamp bank. The provision of a three-wire trunk permits signals to be transmitted in either direction without interference. The substation apparatus is normally controlled automatically according to the load, for example, when a car approaches, the drop in voltage across the main bus-bars 483, 484, Fig. 4, causes a voltmeter 418 to close a circuit for a master relay 415 which operates a contact-maker 416 to start up the rotary converter RC. If, however, the converter is started up by the control operator by means of the connector H<1>, the automatic control is rendered ineffective but may be restored by a particular operation of the connector H' after the converter has first been stopped again by the operator. In addition to supervision of the starting and stopping of apparatus, supervision is also given of changes of voltage across the main bus-bars 483, 484. Means are provided for telephonic communication over the control trunks. The capacity of the system may be increased as in automatic telephony by providing two or more connectors or finders in series. The invention is also stated to be applicable to control by means of high-frequency carrier currents over high-tension power lines or by wireless. A particular example of the use of the system is described with reference to the apparatus shown in Fig. 4, in which it is assumed that a short circuit occurs on a feed-wire 491. A device 531 responds to the increased current in the auxiliary bus-bars 520 and automatically causes the closure of contact-makers 404, 405 and the opening of contactmaker 406 so that the short-circuit is now fed through the resistances 510, 511. These circuit changes are indicated to the control operator by the lamps Land the operator, by effecting the closure of contact-maker 407 and the opening of contact-maker 404 causes the short-circuit to be fed from another substation 526 over the. tiefeeder 521 the resistance of which replaces the resistances 510, 511. Signalling starting of rotary converter RC, Fig. 4. The operation of contact-maker 416 energizes a relay 411 which in turn energizes relay 410, whilst relay 409 is already locked up. A circuit 463, 461, 302, 204, 261 is thus completed for magnet 204 which steps round the finder F until the terminals 224 .. 227 corresponding to the converter RC are reached when relay 243 energizes over conductors 300, 304, and wiper 223, stops the finder, and completes circuit 280, 212, 263 for relay 242 which in turn energizes relays 240, 241. Relay 243 also completes parallel circuits 262, 249, 271 for relay 249, and 262, 201, 257, 271 for impulse relay 201, the latter relay causing the energization of relays 131, 130 at the connector H in readiness for receiving the first set of impulses. Relay 241 closes a circuit 256, 208, for relay 245 which in turn energizes relays 247, 246. Stepping magnet 250 now energizes over the circuit 268, 282, 250, 276, 272, 206 and opens the circuits of relays 201, 249, the former transmitting an impulse over the trunk conductors 191, 192 to relay 131 by which it is repeated to the vertical magnet 140, whilst relay 249 opens the circuit of the stepping magnet which on de-energizing advances the wipens 280 . . 283 of the switch CD one step and re-energizes relays 201, 249. This operation continues until wiper 281 reaches terminal 297 when relay 202 energizes over the circuit 281, 297, 226, 222, 302, 463, steps the switch CD, maintains relay 201 energized over contact 209, and de-energizes relays 247, 246, 245. The pause in the transmission of impulses causes the relapse of slow-release relay 129, Fig. 1, which remained energized throughout the vertical movement, and thus prepares a circuit for the rotary magnet 141. ' The de-energization of relay 245 closes a circuit 269, 250, 170, 283, 271 for magnet 250 which steps the switch CD round until the wipers reach their 13th contacts when magnet 250 is disconnected and relay 248 energizes over wiper 283 and unlocks relay 202 which, on de-energizing, re-energizes relays 245, 247, 246 so that the original circuit of magnet 250 is again completed. The transmission of the second series of impulses now proceeds in a similar manner, the impulses being repeated by relay 131 over the circuit 150, 139, 137, 134, to the rotary magnet 141, until wiper 281 reaches terminal 294 when relay 202 again energizes over the circuit 281, 294, 306, 468, 303, 221, 463. and operates as before to stop the transmission of impulses. The relapse of relay 128 at the end of the series connects ground to wiper 160, thereby energizing relay 103 which locks up, lights lamp 106 and extinguishes lamp 107. Upon the de-enargization of relay 245, the switch CD is stepped on as before until the twenty-fifth set of contacts is reached when relay 242 is disconnected and relay 244 energized. The subsequent release of relays 240, 241, unlocks relay 202 and opens the circuit of relay 201. The consequent release of relays 131, 130 closes a circuit 150, 139, 138 for the release magnet 142 of connector H. The operation of relay 244 energizes relay 203 which, by directly grounding conductor 301, unlocks relays 409, 410 whereby relay 243 is released. In the 25th position of wiper 283, magnet 250 energizes over contacts 269, 270, 296, 295, 283, 271 and advances the switch CD to its first (normal) position in which relay 244 is disconnected and relay 203 released. Relay 411 being still energized, relay 410 locks up. Signalling stopping of rotary converter RC. When relay 411 de-energizes, relay 409 locks up and starts the finder F as before, the code-sender operating in a similar manner, which however is modified by the de-energized condition of relay 411, to transmit series of impulses which bring the wiper 160 into engagement with a terminal such as 169, when relay 103 is short-circuited, lamp 106 extinguished and lamp 107 lit. Signalling change of voltage across bus-bars 483, 484. Relays 500, 501, 502 or a contact-making voltmeter are bridged across the bus-bars and when the voltage drops sufficiently to cause, for example, relay 500 to de-energize, a set of relays associated with its armature and similar to the relays 409, 410, 411 causes the transmission of a supervisory signal in the manner already described. Control of substation apparatus by control operator. The operator's calling device S is bridged across trunk conductors 190, 191 by closing key K and in response to two sets of impulses transmitted from the device S, the connector H<1> operates in a manner similar to that of connector H to associate its wiper 350 with a particular bank terminal. For example, if it is desired to start the converter RC, wiper 350 engages terminal 354 so that relay 414, Fig. 4, operates overconductor 550 and effects the same starting operations as did the master relay 415. The energization of relav 411 effects as before the transmissionof a supervisory signal to indicate that the desired operation has been completed. Relay 414 locks up over contacts 473, 471, thus cutting outthe automatic control through voltmeter 418. In order to stop the converter, relay 413 is energized over wiper 350 and opens the circuit of contactmaker 416. Relay 413 unlocks relay 414, but. itself locks up over contact 470. The automatic control is rendered effective again by the control operator dialling a particular code which operates relay 412 to unlock relay 413. The control of contact-makers 404 .. 408 by the control operatortakes place in a similar manner, for example, contact-maker 406 is connected to a set of relays 490<1>, 491<1>, 492 which correspond respectively torelays 412, 413, 414.