Patent GB-213537-A (GB)
Title: Improvements in or relating to the control of apparatus at an electric power substation from a central control office
IPC: H02J13/00
Filed: 1924-01-08
Abstract: 213,537. Automatic Telephone Manufacturing Co., Ltd., (Assignees of Richardson, R. G., and Bellamy, J. I.). March 30, 1923, [Convention date]. Selective distant control systems; order apparatus.-A system for the distant control and supervision of an automatic power substation comprises means for selectively controlling the machines thereat by impulses transmitted from the control station, and for indicating at the control station the stopping or starting of each machine or any other desired changes of condition. After the operator at the control station has transmitted a control signal, a checking indication is sent back to him, and a further signal must be sent to the substation before the required operation is effected. Means are also provided whereby the operator can check the condition of any piece of apparatus at the substation. The invention is described as applied to the distant control of an automatic power substation at which a motor generator MG, Fig. 2, transforms threephase alternating current, supplied over the leads 215 - - 217 ,and the starter S, into direct current which is fed to the bus-bar 260 over a circuit breaker CB. The various controlling operations are selected at the substation by a switch E, Fig. 2, which is operated by dialling impulses sent over control leads 47, 48, extending from the control station. A signalsending relay set, such as the relays 301 - - 303, Fig. 3, is provided for each position of the switch E, and according to the setting of this switch a corresponding relay set is actuated over the upper wiper 85, and through the medium of a counting switch CS and relay group RG controls the transmission of checking impulses over two signal conductors 49, 50, terminating at the control station in a switch D, Fig. 1, which effects the operation of signal lamps such as L<1>, L<2>. Two lamps are provided for each piece of apparatus, one indicative of its operated condition and the other indicative of its normal condition. By sending a further controlling impulse over the leads 47, 48 the operator can then ground the lower wiper 86 of the switch E and cause the desired operation to be carried out. Each apparatus unit, such as the starter S, is arranged to ground, according to its operated or non-operated condition, one of two conductors 118, 119, associated with corresponding signal-sending relay sets 301 - - 303, in order that when a change takes place (due either to control by the operator or to automatic control within the substation) a corresponding indication is given to the operator by means of the counting switch CS, relay group RG and switch D. The selecting switches D, E, are twocoordinate step-by-step selectors of the wellknown Strowger type. Control of motor generators MG, Fig. 2, from the control station; preparation of control. The operator first presses the key K, Fig. 1, closing circuits for a slow-release relay 17 and a slow-to-act relay 16. The relay 17 closes a bridge across the control conductors 47, 48 and is shortly afterwards de-energized on the response of the relay 16, which places a further bridge across the conductors 47, 48, and at armature 19 prepares a circuit for the lower winding of a relay 24 which is energized on the relapse of the slow-release relay 17. The relay 24 connects up the wiper 22 and opens the circuit of a warning relay 10, in this manner preparing the switch D for operation as a checking switch. The delay in the response of this relay due to the above operation of the relays 16, 17, permits the switch D to complete the indication of any signal the transmission of which from the substation may have been started. The closure of the bridge across the conductors 47, 48 energizes the line relay 60 of the control switch E, Fig. 2, at the substation. The operator now dials the number 11 on the impulse transmitter CD, to set the contral switch E to the position in which the operation of the starter S is prepared. The switch E operates in well-known manner, the first digit raising the wipers 85, 86, to the first level of contacts and the second digit rotating them to engage the first contacts 87, 88 in this level. Transmission of check signal to control station. At the termination of the rotary motion, when the slow-release series relay 63 relapses, a circuit (159, Fig. 3, 123, 87, 110), is completed over the wiper 85 for a relay 64, and for a relay 303, Fig. 3, of the check signal relay set 301 - - 303. The relay 64 looks up over its upper winding and applies direct earth to the wiper 85, whilst the relay 303 locks up over its armature 307 and connects first and second digit stop conductors 128, 127 over its armatures 309, 310 to appropriate contacts of the counting switch CS. In the present instance, since the switch E has been set to its eleventh position both conductors 128, 127 are connected to the first impulse lead 181. The relay 303 also grounds the lead 126 at armature 311, energizing the relays 140, 141, 142, 143, 144. The. relay 140, which is rendered slow to act by being highly inductive and stiffly adjusted, energizes a cut-off relay 301. Relay 142 at armature 162 closes a bridge across the signalsending conductors 49, 50, causing the response of the line relay 29, Fig. 1, of the checking switch D, which is prepared in known manner, whilst the impulsing relay 144, begins to vibrate under the control of the interrupter I. On the first response of the relay 144, the counting switch stepping magnet 176 is energized, and on its relapse, moves the wipers 178, 179 to a sub-normal contact set, in which position a relay 145 is energized over the wiper 178, and at armature 167 removes a short-circuit from - across the impulsing armature 165. Subse- - quent energizations of the relay 144 are thereby effective to open the bridge across the signal conductors 49, 50 and control the vertical movement of the switch D. In the present case when one impulse has been sent and the wipers 178, 179 moved to the second contact set, a stopping circuit is completed over the conductors 128, 181 and the wiper 179, for a relay 146, which locks up, disconnects the sending relay 144, and closes a restoring circuit for the switch CS. A circuit is also closed for a relay 136, which completes a circuit for a change-over relay 137, which, however, does not pull up until a shunt across it is removed on the wiper 179 regaining its normal position and the relays 145, 146 relapsing. The relay 137 transfers ground at armature 151 to the second digit stop conductor 127 and the operation is repeated, impulses in accordance with the second digit, in this case also one impulse, being sent to the switch D to control its rotary movement. On the restoration of the switch CS after the transmission of the second digit, the relay 139 pulls up, de-energizes the relay 142 and at armature 155 closes a circuit over conductor 122 for a relay 135, which places a holding bridge across the conductors 49, 50. The relapse of relay 142 de-energizes the relay 143 and unlocks the relay 303; ground thus being removed from the conductor 126 at both armatures 311, 163, and the relays 136 - - 141 being de-energized. In response to the two series of check signal impulses, the switch D, Fig. 1, in known manner sets its wipers 22, 23 upon the first set of bank contacts 8, 9 in the first level, and on the relapse of the slow-release relay 26, the flasher F is connected over the wiper 22 to the signal lamp L<2>. If the wrong lamp flashes, indicating that the control switch E is incorrectly set, the operator releases the key K, thereby de-energizing the relay 16, which opens the bridge across the conductors 47, 48 and causes the relapse of the line relay 60 of the switch E. Relay 63 energizes and opens the circuit of the holding relay 135, Fig. 3, which opens the bridge across the conductors 49, 50 and de-energizes the line relay 29 of the switch E. The switches D, E restore in known manner. Completion of the prepared switching operation. Assuming that the operator has received the correct check signal, he now dials a further digit 1 and releases the key K. A single impulse is sent to the relay 63, and when the line relay 60 again pulls up, a circuit is completed for a relay 65 which grounds the wiper 86 to operate the starter S. The response of the relay 63 unlocks the holding .relay 135 which opens the bridge across the conductors 49, 50 and releases the switch D. In the normal position of the dial CD, the off-normal springs 15 are opened and the relay 16 de-energizes permanently opening the bridge across the conductors 47, 48 and causing the release of the switch E. The grounding of the wiper 86 energizes a relay 241 which locks up, closes a circuit for a slow-to-act relay 240, and energizes a solenoid 230. The solenoid 230 attracts its plunger 228 and rotates the lever 226, causing all the switch-arms 218 - - 223 to engage their left-hand contacts. The three-phase supply leads 215 - - 217 are thereby connected over the reduced potential taps of the auto-transformer to the motor generator MG, which in starting draws a heavy current sufficient to operate a relay 238 shunted across a resistance 224 in one of the leads. The relay 238 opens the circuit of the relay 240 before it has had time to pull up, but when the motor generator MG has picked up sufficient speed to approach synchronism, the reduced intake of current permits the marginally-adjusted relay 238 to fall away, and the relay 240 responds, de-energizing the solenoid 230 and energizing the solenoid 231, which rotates the lever 226 and causes the switch-arms 218 - - 223 to engage their righthand contact, thereby directly connecting the supply leads 215 - - 217 to the motor generator MG. A holding magnet 233 is now energized across a resistance. 228<1>, its armature breaking the locking circuit of the relay 241 and holding the lever 226 in its operated position. The relay 241 de-energ