Patent GB-375325-A (GB)
Title: Improvements in or relating to the supervision and/or remote control of electric power transmission equipment
IPC: H02J13/00
Filed: 1931-03-23
Abstract: 375,325. Electric signalling systems. AUTOMATIC ELECTRIC CO., Ltd., Strowger Works, BURNS, G. A., 4, Lucas Estate, Thomas Lane, Knotty Ash, both in Liverpool, RAYNER, T. R., 2, Stretton Avenue, Wallasey, Cheshire, and GUNNING, P. F., 10, Fairfield Street, Fairfield, Liverpool. March 23, 1931, No. 8919. [Class 40 (i).] Supervisory signals, indicating the positions of circuit-breakers and tap change switches and meter readings are transmitted from a substation to a main station, the meter readings and tap change switch indications being transmitted simultaneously and distinguished either by using currents of different frequencies or by using currents of different strengths and direction. A telephone line between the two stations is used as the transmission circuit, a telephone conversation taking priority over tap change indications and meter readings but is broken into when circuit-breaker indications are about to be transmitted. To prevent power currents from reaching the telephone lines an insulating barrier is placed between the internal and external parts of the system, relay contacts controlling the external circuit being operated by rods of insulating material passing through the screen. A generator in the external circuit is coupled to its driving motor by an insulating coupling. In the system described below direct current is used for all signalling but a system employing three frequencies in the audio-frequency range is fully described in the Specification. General operation. When a circuit-breaker or tap change switch at the sub-station changes its position, a sending switch is arranged to transmit a series of a fixed number of impulses to the main station which are characteristic of all circuit-breaker, tap change switch, and meter positions. If a telephone conversation is in progress when a circuit-breaker changes over, the conversation is suspended for a few seconds whilst the circuit-breaker indications are transmitted, whereupon the telephone circuit is recompleted. Transmission of the tap change switch positions and meter readings is held up until the telephone conversation has terminated. The circuit-breaker indications operate magnetic locking relays which control lamps on a panel diagram. Meter readings are received on mechanical meters whilst the tapchange switch position indications move singlemotion switches wired to lamps on which the new and old positions of the switches are indicated. In addition to the automatic operation, the supervisory train transmission may be initiated by a manual operation at the main station or may be periodically transmitted under control of a time pulse. The telephone system embodied in the system comprises manual boards at both the main and substations but dialling equipment is provided at the main office so that an automatic unit could, if desired, be installed at the sub-station. To enable the following description to be followed the figures 1 .. 12 should be arranged as indicated in Fig. 19 except that Figs. 7 and 8 should be brought together with wires 13, 14 in alignment. Figs. 13 .. 16 which shew the voice-frequency equipment are not described in the abridgment. Transmission of circuit-breaker indications. If a circuit-breaker, say 1BRC, Fig. 11, moves upwards into the closed position, a circuit is completed over 1a of BRS for BRM and CS in series. Relay CS only operates and RSR, Fig. 9, pulls up. RSR locks and shorts the high-resistance winding of CS so that BRM hunts until 1a leaves the commoned set of contacts when CS releases and SE operates to earth on 1b of BSS. Relay SE locks up and completes circuits for operating M and E and for starting the motor MTR which drives generator GNR through the insulated shaft 12. The shaft 12 passes through the insulating screen 15 which separates the internal and external signalling circuits. When the generator GNR is running at the correct speed, relay GEN pulls up, completing a circuit for BSM which interacts with slow release relay E to step BSS. Relay PV pulses in synchronism with E to repeat the impulses over the telephone circuit 13, 14 to the main station, the polarity of the pulses being controlled by RV which is connected over 2b of BSS to the circuit-breaker contacts. The first contact of 2b is unwired so that the first impulse received at the main station energizes polarized relay O and marginal relay ML but the operation of ML at this stage is without effect. Relay OUT is energized and DR pulls up. Relay S operates, and remains up for the remainder of the impulse train, and SR energizes to open the telephone circuit. When E releases, PU, O, OUT, and DR fall away in turn so that MRM de-energizes to step MRS. MRS is thus stepped in synchronism with BSS and as its wipers 1c and 2c are wired out to magnetic locking relays MLR1 .. MLR4, which are of the type described in Specification 374,432. These relays are set into positions which correspond to the positions of the respective circuit-breakers, alterations in position being indicated by a flashing signal in the usual way. When the position of all circuit-breakers has been signalled 2b reaches its thirteenth contact which is wired to positive through a contact of TE. If a telephone conversation had been in progress when signalling commenced, TE would be operated and further signalling would be suspended as described later. If however TE is back a pulse is transmitted of polarity to operate I at the main station. Wiper 2c is wired to SW at this point and this relay is energized and locks when I, and consequently IN, pull up. Switches BSS and MRS continue to step in synchronism until BSS reaches position 33 in which position wiper 5b of BSS leaves the commoning to BSM and engages commoning to CSM, which drives CSS. Similarly wiper 4c of MRS leaves the commoning to MRM and engages commoning to magnet CGM of the counting switch CGS. Setting of composite tap-change and metersending switch. A typical tap-change switch which is situated remote from the sub-station is indicated in Fig. 12. The wiper TSS, which is provided for testing purposes, connects earth to contacts 1 .. 15, each of which corresponds to a position of the switch and when closed connects a marking potential to the bank 1d of TSS. This switch controls the transmission of impulses to the sub-station to set switch TRS to a corresponding position. In the position of the apparatus shown TSC operates over 2d and TP energizes. TP and TTM interact to step TSC, the impulses being repeated over the line circuit to energize TIM at the substation. TRS is this stepped in synchronism with TTS. When 1d reaches the marked contact TCF energizes and locks, releasing TSC and stopping the interaction of TP and TTM. Relay TS energizes in series with TRM and holds during the impulse train, energizing L which, when TS releases, enables RSR to operate to initiate the signal back train. If the tap-change switch changes its position TCF releases, TP and TTM interact to step TTS to normal, but, as TSC is down, the impulses to the sub-station energize THS, instead of TIM, which allows TRS to home. When TTS regains its normal position TSC reoperates and the switches TTS, TRS are set to the new position as described above. Bank 2e of TRS is wired to bank 1f of CSS so that when 2e is marked over 4b of BSS the marking is extended, when 1f reaches the marked position, to energize PL. The contacts of 3f of CSS are wired to contact meters CNM which are of the type disclosed in Specification 356,211. Transmission of tap-change switch positions and meter readings. The mechanical meters MCH at the main station and the tap-change switch indicators, Fig. 3, remain in the positions to which they are set until a new indication is about to be recorded, the system providing that as one set of indications is being recorded, the next switches to be actuated are being reset. Consequently the first transmission from the sub-station is without effect apart from the resetting function. With switches BSS and MRS in position 23 impulsing proceeds and CSM and CGS are stepped. Wiper 6c of MRS closes homing circuits for MCH and STC in turn and no further operation is effective until 25 impulses have been transmitted when MRS steps to position 24 over 1k of CBS and PL releases to allow BSM to move BSS into position 24. In this position a circuit is completed over 4b of BSS for the coils PD1, PD2 of CNM to mark 3f of CSS and over 4b of BSS and 2e of TRS to mark 1f of CSS. Impulsing continues, the impulses energizing O and ML at the main station, relay OUT repeating the impulses received by O over 38 to STM and, as SW is now energized, the impulses received by ML step MCM over 5c of MRS. When 1f reaches its marked contact PL energizes and locks, operating RV over 2b to reverse the polarity of the transmitted pulses so that STM is no longer pulsed and STC remains in a position corresponding to 2e of TRS. One of the lamps TAP1 .. TAP15 is lit over 5h and the old setting in the switch is indicated by a flashing lamp, controlled over 5j of FTC. When 3f reaches the marked position MR pulls up and locks, energizing MG which cuts resistance Rl into the signalling circuit. This resistance is sufficient to prevent ML from pulling up so that MCM is no longer pulsed and records the setting of CNM. It is immaterial whether MR or PL energizes first. When a cycle is completed BSS and MRS step to their next positions and the next meter reading and tap-change switch position are transmitted. When the transmission is completed BSS and MRS regain their home positions and SE, S, SR and SW release. When the attendant operates key RSK, the flickering of lamps is stopped in the usual way and FTM hunts until its wipers are in alignment with those of STC. Faulty transmission. If due to faulty transmission either MRS or CGS is not normal when impulsing ceases, RP is energized over the offnormal wiper, closing