Patent GB-362485-A (GB)
IPC: H02J13/00
Abstract: 362,485. Electric distant control and supervisory systems. SIEMENS BROS. & CO., Ltd., Caxton House, Tothill Street, and HUMPHRIES, H. E., 474, Lewisham Hill, both in London. Aug< >29, 1930, No. 25852. [Class 40 (i).] In a system in which circuit-breakers &c. at remote substations are selectively controlled by stepping-apparatus which operates freely (as distinct from apparatus involving reciprocal step by step control between the transmitter and receiver) the executive signal which follows the selecting signal cannot be sent until a confirmatory signal has been reverted indicating that the selecting operation has been correctly performed. Other features of the system are claimed in Specification 362,484. Specification 280,254, [Class 40 (i), Electric signalling systems &c.], is referred to in the Provisonal Specification. General operation. In the installation described, a control station (Sheets 1 to 7) controls, ten substations on a common four-wire line, one substation being shown (Sheets 8 to 11). Provision is made for operating in one sense or the other ten units (such as circuit breakers) at each substation, or the capacity of a substation may be extended. Each unit is represented by a pair of executive relays FA and an indication relay FZ. To change the condition of a unit, the controller throws a key KOL, individual to the unit, in the appropriate direction. Switches ASF, EOF (the latter individual to a substation) are set to positions identifying the key and its direction of throw and control the transmission of two digits. The first digit (1 to 10) operates switchesBSM at all substations, At the wanted substation the second digit (1 to 20) sets a switch BOP, which selects the unit and according to the odd or even value of the digit determines the sense of operation, The normally energized relay FZ individual to the unit is de-energized and controls the setting of a storage switch CIF, and a 3-digit confirmatory signal is sent back to the control station. The first digit (4 or 6) denotes the sense of the prepared operation and sets a switch DTM. The second digit (2 to 11) identifies the substation and sets a switch DSM. The third digit (1 to 20) identifies the unit and (by its odd or even value) the existing condition of the unit, and sets a switch EOM (individual to the substation). If the reverted signal is correct a third (executive) train of impulses can now be sent from the control station, either automatically or at the will of the controller, and energizes the selected relay FA. Provision is also made for the following operations :-(1) To perform an emergency operation at a combination of substations, the controller throws a key KOLC (not shown) which results in the transmission of a two-digit signal of which the first digit is 24. Switches BSM being set to position 24, the second digit operates switches-BMM which, at the required substations, select executive relays FA(c). In this case no confirmatory signalsare reverted and the executive train is sent without delay. (2) The condition of each unit at each substation is indicated at the control station by a red or green lamp glowing. These and all other supervisory lamps as well as all control keys are situated on a mimic diagram board before the controller. If the unit changes condition its FZ relay is de-energized and, as in the case of a confirmatory signal, causes a 3-digit signal to be transmitted, the first digit, however, being 2 instead of 4 or 6. At the control station this signal causes the growing lamp to go out and the other lamp to flash, the flash being converted to a steady glow when the controller presses an acknowledgment key. To confirm the position of any unit the controller operates the corresponding key KOL and observes the flicker due to the reverted confirmation signal, but refrains from sending an executive train. (3) If the controller desires to read,say the voltage of a particular machine at a particular substation, he throws a key KON individual to the machine. This results in connection of the appropriate meter to a metering line (which may be one of the signalling lines) and transmission of a 2-digit signal. The first digit, identifying the substation, has 10 more impulses than when the same substation is selected for operation of a unit, so that the substation switches BSM are set to .such a position that, at the wanted substation, the second digit sets a switch BMM to select a relay FB individual to the wanted machine. The relay FB in conjunction with a common relay BM connects the bus-bars of the machine to the metering line. If the controller after reading the meter wishes to raise or lower the voltage of the machine, he throws a key KRL (Sheet 2) up or down, whereby one impulse or two are sent to line, followed after a pause by a train which continues as long as the key remains thrown. The one impulse or two operate a switch BPC so as to energize or not to energize a relay BR, and the subsequent train energizes a relay FA(r) or F A(l) accordingly. Having read the voltage &c. of a particular machine, and if necessary raised or lowered it to correct value, the controller may wish to perform an executive operation in respect of the machine. For this purpose he momentarily presses a key KMP, which results in the reversal of the line current; a polarized relay BP, from which a short-circuit has been removed at the selected substation, is energized and operates relay FA(p). (4) Momentary depression of a key KRS initiates a routine test by sending out a signal 23-23, which operates switches BSM, BOP at all substations to energize a relay CW, which causes the reversion of a 3-digit confirmation signal of which the first digit is 2, the second denotes the substation, and the third is 23. The substations one after the other send in these signals to light lamps (one for each substation) at the control station. (5) When the controller lifts his telephone receiver, a one-digit signal 22 is sent to line to bring all substations into a condition in which their call bells may be rung by subsequent impulse trains which are despatched under control of a code ringing key KR. The intervention of the controller is necessary for conversation between two substations. Line and impulsing conditions ; prevention of simultaneous signals from different substations. All signals from the control station to substations are sent over an output line, and all signals except telephone calls from substations to the control station are sent over an input line. Each of these lines is a loop circuit extending through all substations and is normally supplied with current from the control station. The telephone speaking circuit is over the b-wires of the two lines. The normally energized condition of the lines allows faults to be signalled. A telephone call from a substation is given by opening the output line, while prolonged opening of the output line at the control station causes restoration of the signalling and control apparatus at the substations. Output signals consist of trains of interruptions separated by prolonged closures, and are received at the substations by series relays BL. The current in the line is normally insufficient to energize these relays but is increased prior to signal transmission, to prepare the substations. Impulsing is effected by contact az2 (Sheet 3) in positions 2, 5, 9 of AOC(B), and is reinforced by arranging that a relay AE and choke ARC in the impulsing circuit are locally energized over ag2 and the back contact of az2, so that forward movement of az2 sends an inductive surge to line over condenser QS prior to the closure of the line at the front contact. The output line at each substation also includes a polarized relay BP, which may be energized by reversal of the line current to perform an auxiliary control. In the case of input signals it is necessary to prevent two substations from signalling at the same time. This is effected by including in the input line at each substation a relay CL, the de-energization of which energizes a relay CV, which busies the line by opening the energizing circuit of relays CNA, CNB, which must be energized before a signal can be transmitted. Before any signal is sent, relays CNA, CNB at the sending substation open the line to further substations, so as to energize their relays CV. The first interruption of the signal de-energizes CL and energizes CV at the sending substation and at all nearer substations, and CV remains energized until the signal is completed. That this may be so, it is necessary that the interdigital pauses of an input signal should be prolonged breaks, not prolonged makes, and the substation sending apparatus is designed accordingly. At the termination of the signal the final prolonged break is further prolonged by opening the line at DDS(D) at the control station, and the line remains open until the apparatus at the control station has been restored. Any other substation which has meanwhile prepared a signal for transmission keeps the signal stored until the line falls clear, whereupon relays CV relapse and CNA, CNB at the waiting substation become energized and start transmission. If two substations energize their CNA, CNB relays almost simultaneously, there is a possibility that the further substation may send a mutilated impulse to line before it is shut out by the nearer substation, in which case the nearer substation will appear to have sent one impulse too many in its first train. This is remedied by arranging that an odd value of the first digit always produces the same effect as the next lower even value, which is the number normally sent. Meter readings may be taken over the input line, and while they are in course the relays CL are shortcircuited. Operating a selected unit at a selected substation ; storage and transmission of signal. A key KOL (Sheet 7) individual to the unit is thrown in the approp