Patent GB-489000-A (GB)
Title: Improvements in or relating to electric remote indication systems
IPC: H02J13/00
Filed: 1937-01-15
Abstract: 489,000. Electric control and signalling systems. STANDARD TELEPHONES & CABLES, Ltd., McWHIRTER, E. M. S., and WARD, H. J. Jan. 15, 1937, No. 1302. [Class 40 (i)] In a system for indicating at the central station of an electrical power network the condition of apparatus located at one or several related substations of the network, common indicating equipment at the central station is adapted for individual association with the substations to display the condition of all the apparatus at the substations. The substations may be connected directly or through tandem stations to the central station and several substations may be connected on a party line. Remote control of apparatus at a substation may be effected from the central station. General operation. When a change occurs at a substation a line finder connected to the tandem junction hunts for the station line and associates a receiver with the substation. The receiver responds to a code sent in by the substation and marks a tandem sender which transmits two digits, the first of which identilies the calling party line, and the second the particular substation. The signals transmitted by the tandem sender operate apparatus at the central station to initiate the operation of a finder which associates the central station apparatus with the junction and the transmission of signals back to the substation. The reverted signals start the transmission of signals representative of the condition of all the apparatus at the substation. The central station is also provided with two sets of auxiliary supervisory equipment which, after the display of indications on the main equipment. are automatically associated in turn with substations which are closely related to the station in which the original change took place in order that indications of the condition of apparatus in the related stations may be checked. Figs. 4 and 5 show the apparatus at the central station, Figs. 6 and 7 that at a tandem station and Fig. 8 the substation equipment. Line-finder and sender operation at a tandem station. When an apparatus at the substation shown changes its position relay OC pulls up to operate relays KA, ES, PN. Relay ES operates SA which connects battery feed to the substation lines L1, L2. If the tandem, Figs. 6 and 7, is free, relay N pulls up over the lines L1, L2 to initiate hunting of a finder switch F which hunts for the lines L1, L2 and effects operation of relays TR, CO the latter of which extends the substation battery feed to relays IP, IN, Fig. 6. Relay LO2 common to all incoming lines also is operated to prevent operation of further line relays N. Relay SA initiates the operation of stepping relays X, Y of switch SS1 in the substation which steps to its 18th position. During stepping three impulses, the polarities of which are determined by the markings in banks ss2, ss3 are transmitted to effect the operation of appropriate relays in the positive or negative groups of relays A, C, E or B, D, F, Fig. 6. The operated relays select a relay S and also appropriately mark the contact bank ss23 of the tandem sender SS2. When switch SS1 reaches position 18 relay RL pulls up to effect the release of relays KA, ES, PN and SA. In the event that the line L1, L2 is a party line and is busy, relay LOI operates LOR which open circuits relay ES to prevent the transmission of signals from an incoming substation until the line is free. Moreover if the tandem is busy relay LO2 connects battery to all the incoming lines and line relays N are disconnected. The operated relay S pulls up relays CC, SA2 the former of which operates relay PP2 over wiper ss23 and the latter operates relay PN2 and connects relay L across the junction JL1, JL2 the relay L being energized, over the junction provided relay CCO, Fig. 4, is de-energized, to initiate operation of the relays XX, YY for stepping the sender switch SS2, Fig. 7. When the sender steps off normal relay AA pulls up AS to connect battery to the junction and as the switch steps over its contacts, a six pulse code of positive and negative pulses as determined by the marking of the banks ss22, ss23 is transmitted over the junction. The first three pulses are determined by the marking of relay CC and identify the calling party line and the last three pulses identify the remote substation. Reception of code at central station and reversion of checking signal. The code is received at the central station by relays 1P1, 1N1 and operates positive and negative relay chains A1 .. K1, B1 .. L1 the first three pulses selecting a relay AS1, which connects the marking corresponding to the second three impulses to a particular relay S which locks up over the contacts of a station reset key SRK, and pulls up relay ST which initiates hunting of finder F2 up to the contact marked by relay S when relay T 1 pulls up and hunting stops. Relay S also pulls up relays RA, RB, RD individual to the station. The relays RA, RB connect leads KS to the display devices DD in such a manner that the number of devices prepared for operation correspond to the number of apparatus units in the corresponding substation. Relay RD marks the switch SS over leads CML to transmit a checking code back to the substation. Relay TR pulls up CCO which connects the junction lines JL1, JL2 to the finder contacts and also initiates stepping of the sender SS, Fig. 5, which when started pulls up IS to connect battery feed to the junction and operate relay IR in the tandem station. The switch SS transmits two trains of impulses, each train comprising nine impulses and two digits, the impulses operating the relay IR to effect stepping of the switch SC, Fig. 7. At the end of the first digit relay CR releases and a relay CO is pulled up over the wipers of switch SC to switch the junction JL1, JL2 through to the lines L1, L2. The second digit of the first train is then sent via the junction and lines to operate relay 1R, Fig. 8, and the impulses are absorbed in the switch SR. The first digit of the second train further steps switch SR and operates a relay QA whilst the second digit pulls up a relay QT. A third train of impulses is then transmitted by the central station switch ST which is brought into action by the switch SS, pauses being introduced in the train in a characteristic manner according to marking determined by relay CKR to effect operation of relays AA, AK. At the termination of impulsing the selected relay CK, Fig. 8, is operated and at contact ck3 closes a self-drive circuit for the switch SS1, Fig. 8, which hunts to position 18. In the central station, at the termination of impulsing both sender switches step to the home positions and battery feed is disconnected from the junction. Consequently relay IR, QA, QT, AA, AK are released but relay CK, Fig. 8, remains locked up. Supervisory signalling. The substation switch now transmits a series of impulses to indicate the condition of all the apparatus at the substation as determined by positive markings applied to the bank SS3 by the OL relays. The positive and negative impulses transmitted operate through the intermediary of relays IP2, IN2 the central station switch SR and selected relays in a group AA ... AK are operated by the positive impulses. Indications are thus given on pairs of lamps GL, RL of the condition of all the substation apparatus. When the sending switch SS moves to its final position relay RL is pulled up to effect release of the sending and receiving switches. The condition of apparatus at any substation may be ascertained by the operation of the station key SCK to set up the connection to the station and initiate the transmission of the supervisory code. Ascertaining condition of apparatus in other substations. When the central station finder F2 is set on to a calling junction the wipers fm28, fm29, mark contacts in the banks of auxiliary finders over leads MF1, MF3. When supervision from the main station is completed potential is applied over start lead STF1 and the first auxiliary finder switch hunts to select a junction and mark sender switches similar to SS, ST which select a first related substation and initiate the transmission of supervisory signals therefrom. When this operation is completed, the second finder switch hunts and supervision of a second related station is effected. Control of substation apparatus. Apparatus at a station may be selected for operation from the central station under the control of the switches SS, ST.