Patent GB-612724-A (GB)
Title: Improvements in or relating to electrical remote control and/or supervisory systems
IPC: H02J13/00
Filed: 1946-02-01
Abstract: 612,724. Electric selective signalling systems. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., and BURNS, G. A. Feb. 1, 1946, No. 3216. [Class 40 (i)] A remote control and/or supervisory system for an electric power network in which the position of circuit-breakers at substations is signalled to a control station by an impulsing device employing a spring-driven gear train, the impulsing devices being in series in the line and interference being prevented if more than one is required to transmit simultaneously. General description.- A central station is connected in series with a number of sub-stations; the operation of a circuitbreaker at a sub-station causes the transmission of a characteristic signal which actuates a corresponding indicator at the central station; provision is made to prevent any sub - station signalling until the line is clear; where the line current is D.C. (Figs. 1 and 2), the central station can signal back by reversing line current to actuate. equipment at the sub-stations, but where the line current is A.C., the central station cannot signal back (Figs. 3, 4 and 5). Signalling from a sub-station when line current is D.C.-The operation of the circuit-breaker at a sub-station SS, Fig. 2, energizes trip magnet TM to release a clock-work driven characteristic impulsing wheel IW; contacts ON are also opened mechanically so that windings MSC are energized to maintain contacts ON open during the test period corresponding to the long first tooth on the wheel IW; if, during this period, the line current is interrupted by another substation, windings MSC are de-energized and contacts ON close and are held closed since the armature falls away to a position from which it cannot be attracted by windings MSC so that no signals are emitted by the opening of contacts IMP; after the wheel IW has made one complete rotation however, contacts ON are opened mechanically again for a further test; if no other sub-station is signalling, contacts ON remain open, and the impulse wheel opens and closes contacts IMP to send a signal consisting of a characteristic number of pulses terminating in a long pulse and thereafter the contacts ON close. At the central station CR, Fig. 1, the signals intermittently de-energize relay L, Fig. 1, to intermittently energize relay LA, slow-release relay C remaining energized until the final impulse is received; relay LA energizes slow-release relay B to open at B1 the homing circuit of wipers R2, R1, and energizes relay RM to step on the wipers R1, R2; the final long pulse allows relay C to de-energize to connect wiper R1 to positive at C1 and energize a relay 5R which holds on over 5R1, lights the corresponding indicating'lamp L5, and opens contacts 5R3 to prevent the transmission of a signal from the central station. When relay L is steadily energized, relay LA remains released so that relay B falls off to close at contacts B1 the homing circuit for wipers R1, R2. Manually-operated key 5KR allows relay 5R to be de-energized. Signalling from the central station, line current being D.C.-A key KS, Fig. 1, is closed corresponding to the sub-station to be controlled; relay SD energizes over its upper winding to hold on over contacts SD1, to mark a contact on bank S1 over contacts SD2, and to connect wiper S2 to positive; relays E, RV and PCX are thus energized. Relay RV reverses the line current at RV1, RV2. Relay E actuates line pulsing contacts E3, energizes the stepping magnet SM over contacts E 1 and actuates relay BP over contacts E2, which opens the circuit of relay E at BP 1 to open the circuit of the stepping magnet SM and step on wipers S1, S2, S4. Relays E and BP thus interact until wiper S1 reaches the marked contact. Relay PCX is slow to act and releases the short circuit of relay PC so that relay PC is energized when S reaches the marked contact; relay BP energizes over contact PC1 and the interaction of relays BP and E is stopped and a long pulse is transmitted over the line. Relay PC also de-energizes relay PCX which short circuits relay PC. When wiper S1 reaches the marked contact, the lower winding of relay SD is energized to counteract the effect of the upper winding, but the opening of contacts SD3 has no effect on relays E, BP since wiper S2 is on its arc. Relays E and BP again interact sending impulses until the wipers S1, S2, S4 reach their'starting positions. At the sub-stations, relays LS, Fig. 2, are energized by the reversed line current to energize slow release relay SC which short circuits windings MSC at SC3 and prepares circuits for relay SB (at SC1), stepping magnet SRM (at SC2) and opens the circuit of wiper SR2 (at SC4). Incoming signals actuate relay LSA which energizes slow release relay SB, connects wiper SR2 to positive and energizes the stepping magnet SRM to step on the wiper SR1, SR2, SR3. Relay SB disconnects wiper SR1 from positive and energizes relay SBX which disconnects wiper SR3 from positive at contacts SBX1 and prepares a holding circuit for relay IR at contacts SBX2. When the long signal is received, relay SC releases to close contacts SC4 and energize relay IR over the bank contact; relay IR holds on over IR2 and lights a lamp, and closes contact IR1 preparing a circuit for the controller energized from lead 19. Relay SC also releases relay SB which completes the circuit at SB1 of the controller energized from lead 19. The subsequent signals step the wipers SR1, SR2, SR3 back to normal. Modification employing A.C. line current.- In this modification, signalling can only occur from the sub-stations, Figs. 4 and 5, to the central station, Fig. 3. Each sub-station, Fig. 4, has two circuit-breakers which respectively reverse contacts 1CB, 2CB, open contacts ON and start the clock-work for driving the impulse wheel IW. Testing for a clear line proceeds during the first long (test) impulse as described above. Assuming that no other substation is transmitting, the wheel IW rotates to open the line at IMP and to step on wiper AD. At the central station, Fig. 3, relays N, R release when the line circuit is opened at IMP completing circuits for relays NN, RR which close contacts NN1, RR1 to energize stepping magnet RM to step on wipers R1, R2; relays NN, RR also change contacts NN2, RR2, but produce no effect on relays CON connected to bank contacts R1. Release of relays N, R also energizes slow release relay B over N1, R1 which maintains a circuit prepared at B for relays NN, RR. When the wiper AD, Fig. 4, reaches the bank contact connected to ICB, the inclusion of rectifier MRD in the line circuit ensures that only relay N, Fig. 3, operates so that only relay NN operates and contact NN2 is changed to energize the corresponding CON relay in such a direction that it does not change its contacts CON1 to change the indicating lamp LC to LO. If contacts ICB, Fig. 4, had been changed, relay R, Fig. 3, would have operated to cause contact RR2 to change to energize a relay CON to change its contacts CON1 to energize a lamp LO in place of a lamp LC. The signal terminates in a long interruption to release relays N, R, for sufficient time to allow relay B to release to close contact B2 and complete a homing circuit for wipers R1, R2.