Patent GB-650755-A (GB)
Title: Arrangement for checking the train of reply impulses in selector systems for remote control
IPC: G08C25/02
Filed: 1946-04-29
Abstract: 650,755. Electric selective signalling. ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET. April 29, 1946, No. 12816. Convention date, May 9, '1945. [Class 40 (i)] The invention relates to a system for the remote control or indication of the position, "open," or "closed," of circuit-breakers or other apparatus in one or more substations, in which an initiating impulse train consisting of two kinds of impulses (e.g. positive and negative or short and long), is transmitted from one station to another, there being one impulse in the train for each position " open, " and " closed," of each circuit breaker at the operative station, impulses of one kind, e.g. long, being transmitted when a control operation or indication is to be effected and of the other kind, e.g. short, where no control operation or indication is to be effected, and wherein a corresponding reply impulse train is reverted to the first station for comparison with the initial impulse train before the executive signal to effect the control or indication is sent. According to the invention each station comprises a sender and receiver selector with corresponding positions mutually interconnected, an impulse determining member for each position of the transmitting selector, and a member co-acting with the receiving selector in the initiating station which interrupts stepping of the selectors and zeroizes them if the initiating and reply impulse trains do not correspond. The system is described for one substation only but may be extended in known manner to cater for several substations connected to one control station. Control signal, operation, Figs. 1, 3. To open the circuit breaker associated, e.g. with contacts 1, 2 of the selectors SS, MS, at the substation, Fig. 3, contact 1 being for " close " control and contact 2 for " open " control, register relay R1<SP>11</SP> associated with contact 2 of the selectors SC, MC at the control station, Fig. 1, is energized by closing a corresponding switch R1<SP>11</SP>b and locks over R1<SP>11</SP>a. This initiates transmission of an impulse train, e.g. as described in Specification 650,756 and, in a manner not shown, stepping of the control station sender selector SC and substation receiver selector MS is effected synchronously with the impulses. Short impulses are sent for each selector SC contact associated with an unoperated register relay. In position 2, however, as the associated register relay R1<SP>11</SP> is energized, a relay SMIC pulls up and causes a long impulse to be sent. Long impulses are thus sent only in those selector positions for which a control operation is required. At the substation a relay is operated by long impulses only to close contacts MM1<SP>s</SP>a which connect positive over the associated bank contact of the receiver selector MS to operate the associated register relay R2<SP>1</SP>, R2<SP>11</SP>, &c. In the example quoted register relay R2<SP>11</SP> connected to contact 2 of selector MS will be operated and locks over contacts R2<SP>11</SP>a, OMaS. The reply impulse train is initiated as described in Specification 650,756, and the substation sender selector SS and control station receiver selector MC step synchronously therewith. Short impulses are sent for all contacts of the sender selector SS except for those marked with +ve by an operated register relay such as R2<SP>11</SP> when a relay -SM1S is energized to send a long impulse, as for impulse transmission from the control station. At the control station, Fig. 1, each impulse of the reply train is checked as to its length against the position " energized " or " de-energized," of the corresponding register relay by analysing relays MM1, MK1 (not shown). For short signals relay MK1 only is energized and closes contacts MK1c to energize a reply check relay FKC2 in series with the associated unoperated register relay. The current flow in this case is insufficient to operate the register relay but the check relay operates to indicate correspondence of the position of the respective register relays concerned. For long impulses the relay MM1 only is operated and the check relay winding FKC1 is energized from the positive locking the associated energized register relay, over contact R1<SP>11</SP>a for example in the case quoted above. In the event of lack of correspondence between a reply checking impulse and the position of the associated register relay, neither of the check relay windings FKC1 or FKC2 is operated, whereupon, in a manner not shown, the selectors are zeroized and a fresh cycle initiated. Indication signal, operation, Fig. 2. Position indicating relays A1, A2 at the substation each have two pairs of serially connected windings, a pair 1-2, 3-4, for each position, e.g. the " on " and " off " positions of the associated circuit-breaker. One winding 1, 3 of each pair serves for changing the indication, the other winding 2, 4 serving to lock the first relay in the associated position. The circuit breakers or other controlled objects at the substation control two-way contacts 1K1, 1K2 ..., according to their position. If contacts 1K1, for example, are now changed over by operation of the associated circuit-breaker, the windings 1, 2 of relay A1 are de-energized to initiate stepping of the sender selector S2S synchronously with the transmission of an impulse train to the control station. The only contacts of the selector marked by + ve from 1K contacts are those where a change of state is to be indicated. Thus short impulses are sent where no change is to be indicated but in position 2 of the selector a relay SM12<SP>s</SP> is energized to send a long pulse as previously described. At the control station a reply impulse train is, as above described, sent in response to the received train. The reply impulse train steps the receiver selector M2S and is analysed by relays MM1, MK1 (not shown), responsive to long and short impulses respectively as previously described for control impulses. Short impulses cause the check relay FKS3 to be energized over the associated selector contact and resistor M1, or M2 provided that the corresponding indicating relay A1, A2 ..., is energized. Long pulses cause the check relay windings FKS1, FKS2 to be energized over the associated selector contact in series with the corresponding position indication relay winding. In the example quoted the winding Al 3  would be connected in series with the check relays in position 2 of the selector and after the check relay had shortcircuited its winding FKS 2  to increase the current flow, the winding Al 3  would operate the position indicating relay to the position corresponding to the new position of the associated circuit-breaker, where it is locked by the winding Al 4  in series therewith. Should any impulse of the reply train fail to agree with the " position " of the associated circuitbreaker the procedure is interrupted and a fresh cycle initiated.