Improvements in or relating to systems of electrical remote control or supervision

Abstract

Abstract 359,576. Distant control systems. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London, and SMART, N. C., of General Electric Co., Stoke, Coventry. Dec. 3, 1930, No. 7061. [Class 40 (i).] In a system of remote control or supervision having selective switching apparatus controlled from a remote point by signals transmitted over line wires to energize desired circuits, in which signals may be originated from different groups of circuits having different orders of priority so that if, at the same time, two or more signals are prepared for transmission from different groups, the signals are transmitted in the order of their relative group priority, during transmission the signals are automatically checked back over the same line wires. The invention is described with reference to Figs. 1 to 6, which should be arranged as shown in Fig. 6, Figs.l to 3 representing control station apparatus, and Figs. 4 to 6 apparatus at a substation. The control station is provided with the following selectors-a sending group selector SGS, a number of selectors SSA, SSB, &c., adapted to be selected by the selector SGS, and controlling the transmission of different groups of signals, a receiving group selector RGS, and a number of receiving selectors such as RSA, these receiving selectors and receiving group selector being provided as a check against faulty signalling, a sending sequence selector SQ and a receiving sequence selector RQ. The substation is provided with a sending group selector SSGS, a number of sending selectors such as SSSA, a receiving group selector SRGS, a number of receiving selectors such as SRSA, a sequence sending selector SSQ, and a sequence receiving selector SRQ. The selectors are driven by magnets when de-energized. The magnets of the sequence switches have self-interrupting contacts. The control station has a line relay L adapted to be connected through lines 4, 5 to a line relay SL at the substation. Each of these relays has two windings, and when the currents in the two windings are equal the relay is inoperative. These relays are adapted to co-operate with the sequence selectors in the control of the sending and receiving selectors. Actuation of substation apparatus. The operation of moving a control key, Fig. 3, from the " open " to the " close " position causes the operation of relay SF to mark the 3rd contact in the bank of wiper SGS5. The 21st contact in the bank of wiper SSC3 is also marked by way of line 51. Relay SF initiates the operation of sequence switch SQ and through this switch, the operation of sequence switch SRQ. These switches control the group selectors and the sending and receiving selectors, so that the group selectors SGS and SRGS step round until the 3rd contact is reached whereupon the group selectors are caused to cease stepping and the selectors SSC, SRSC now step round until the 21st bank contacts are reached. The sequence switch SQ then steps from the 8th to the 9th position and initiates the operation of the checking selectors. The sending group selector SSGS at the substation and the receiving group selector RGS at the control station step round until the 3rd contact is reached when, owing to the fact that the bank of contacts associated with wiper SRGS3 is connected to corresponding points in the bank of contacts associated with wiper SSGS3, a circuit is complete through the 3rd bank contact of wipers SSGS3 and SRGS3 to cause the sequence switch SRQ to step to its 9th position, whereby the group selectors are caused to cease to step. Impulsing is now commenced by selectors SSSC and RSC, these selectors stepping round until the 21st bank contact is reached, when impulsing ceases, this result arising from the fact that the corresponding bank contacts associated with wipers SRSC2 and SSSC2 are connected. The sequence switch SRQ steps through its 13th position, in which position wiper SRQ2 causes relay SSO to be energized. If synchronism has existed in the stepping of corresponding selectors a circuit is complete for the sequence switch SQ which then moves from the 15th to the 17th position, causing the switch SRQ to step from its 14th to its 15th position. A circuit is then complete from earth through contacts SH1, wiper SRQ3 and 15th bank contact, wiper SRGS5 and its 3rd bank contact, operated contacts SSO1, wiper SRSC4 and its 21st bank contact, lead 201 to the operating coil SCBC which operates to close the circuit-breaker corresponding to the operated control key. Contacts SCBC1 are closed by means of which the sequence switches SQ, SRQ are caused to step to normal position and the winding of relay P, Fig. 3, is operated to extinguish a green lamp GL and light a red lamp RL, indicating that the circuitbreaker has closed. Operation of substation apparatus automatically or manually at the substation. Assuming that the circuit-breaker shown in Fig. 6 has closed automatically or by manual control contacts SCBC1 mark the 21st bank contact of wiper SSSC3, and contacts SCBC2 operate to energize relay SSF. Contacts SSF1 connect earth to the 3rd contact of the wiper SSGS5. Contacts SSF2 cause the stepping of switch SSQ to its 2nd position, which initiate the operation of the sequence switch RQ and the group selectors SSGS and RGS. The group selectors step round until the 3rd bank contacts are reached. Under the control of the sequence switches the selectors SSSC and RSC then step round until the 21st bank contacts are reached. The group selectors SGS and SRGS are next caused to step round until the 3rd bank contacts are reached. Selectors SSC and SRSC then step together until the 21st bank contacts are reached. If the various corresponding selectors are in synchronism sequence switch SSQ steps to its 17th position and operates relay L which acts to step sequence switch RQ to its 15th position. A circuit is then completed from earth, through contacts H1, wiper RQ3 and its 15th bank contact, wiper RGS5 and its 3rd bank contact, lead 15, wiper RSC3 and its 21st bank contact, lead 53 to the " close " coil of relay P. This relay operates and at contacts P2 extinguishes the green lamp GL and lights the red lamp RL, indicating the closure of the circuitbreaker. The sequence switches RQ, SSQ step round to home positions. While the wiper RQ3 is resting on the 23rd and 24th contacts a circuit is completed through relay PA which locks up and at contacts PA2 closes circuits to cause the operation of the alarm buzzer AB and the lighting of lamp PA, these signals being rendered inoperative when the operator at the control station moves the control key to the " close " position. Telephone communication. The telephone instrument at the control station is connected between leads 403 and 404, and when the receiver is lifted a loop circuit of low ohmic resistance is completed to operate relay TH. Contacts TH4 operate relay C, contacts TH3 cause relay SF, Fig. 3, to operate, and contacts TH2 mark a contact on the bank of wiper SSC3. The resulting operations are similar to those described as resulting from the operation of the control key shown in Fig. 3, but in this case relays STC and TC are operated. Contacts STC4, Fig.5, complete a circuit for a vibratory relay SRV which at contacts SRV1 causes relays SRH and SR to operate. SRH at contacts SRH1 opens the circuit of relay SRV causing this relay to vibrate. Relay SR follows the vibrations but slow-release relay SRH holds over the vibrations. A circuit is then complete which includes the leads 401, 402 to the telephone instrument, and the contact SR1, the latter moving in accordance with the vibrations of the relay SRV and thereby causing the telephone bell to ring. When the receiver is lifted the bell and a condenser are short-circuited by a lowresistance loop so that current through one coil of relay STH causes the relay to operate. Contacts STH3 cause the energization of relay MF, and contacts STH4 release relays SR and SRH. Contacts SRH2 connect earth through the second coil of relay STH to the telephone circuit. Contacts STH4 also operate relay SC which at contacts SC4 disconnects relay SRV and locks through contacts SC1 to contacts STC4. Conversation can now be carried on, which does not interfere with signals sent over the main lines, but impulsing on these lines will be heard in the receivers and will therefore delay conversation until the impulsing has ceased. When conversation has finished, assuming that the substation receiver is hung up first, relay STH releases and at contacts STH2 completes a circuit through relay SSF. At contacts STH1 it marks a contact on the bank of wiper SSSC3. Impulsing proceeds as described with respect to the automatic operation of a circuit-breaker. Ultimately relays STC and TC are released and since the control station receiver is hung up relays TH and C also release. If a call is initiated at the substation the relays RV, R, and RH, Fig. 2, act to supply ringing current in a manner similar to that of the relays SRV, SR, and SRH. Indicating change in the position of a tapchanging switch. Contact arm TG3, Fig. 6, is connected to the main shaft of the tap-changing switch and moves with it over the contacts shown. Each contact is wired to one contact of the bank of a sending selector SSSB. Assuming that the tap-changing switch steps from the contact connected to lead 217 to the contact connected to lead 216, relay RF, which has operated and has locked up through contacts RF2 and contact arm TG3, releases and at contacts RF3 (shown operated) completes a start circuit over leads 209, 210. Contacts RF1 (shown operated) extend earth through normal contacts SSF1 to mark the 2nd contact of bank SSGS5. Such marking can only be given if SSF is normal, so that if any signal is sent by any selector associated with the " C " group of signals, after the tap-changing switch signal has been started but before the sending group selector has reached the marked point, the marking earth is

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