Patent GB-409472-A (GB)
Title: Improvements in or relating to electrical systems of remote control and supervision
IPC: H02J13/00
Filed: 1933-01-31
Abstract: 409,472. Electric signalling and distant-control systems. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London, and SMART, N. C., c/o General Electric Co., Stoke, Coventry. Jan 31, 1933, No. 2982. [Class 40 (i).] In a system for remote control and supervision of apparatus units comprising at least two signalling channels between a controlling and controlled station, selectors are connected at each end of two channels and have groups of contacts allotted to the apparatus units, the number in a group corresponding to the number of positions the unit may occupy, and a change occurring at either station resulting in signalling over both channels so that the selectors of one channel are set in the required group and according to the change while the selectors of the other channel are set to the required group. If a change is to be effected from the controlling station, the selectors of the two channels are set respectively in the position indicating the change and in the position indicating the existing condition. The correctness of the selection is checked and the operate signal is then sent over one of the channels or over an additional channel, and when the change has taken place the selectors of the second channel step on to the new position and a supervisory signal is given. In a complete system only units of major importance, e.g. circuit breakers, are allotted the full number of contacts according to the positions they may occupy. Other units such as meters and tap-changing switches, which would incidentally require a large number of contacts, are normally in effective connection with only part of a full group but are put into effective connection with necessary additional contacts on receipt of a special signal. The additional contacts may be available in common to these apparatus units and also to major units. When a change occurs at the controlled station, the condition of the whole of the units of major importance is signalled by a series of successive operations of the selectors. The expression " two channels " includes duplex signalling over a single physical channel, and by using voice and carrier frequencies the signalling in the two directions may be simultaneous. As described, D.C. impulses are used over a single metallic circuit, the signalling for the two directions or " channels " taking place in succession. Circuit breaker control and supervision, Figs- 2, 1, 5 and 6 arranged in the order specified. It will be assumed that the circuit breaker, Fig. 6, is open and it is desired to close it. Key TW of the controlling apparatus Fig. 2, individual to the circuit breaker, is thrown to the left operating CS in the common controlling circuit, Fig. 1, and marking one of a pair of contacts (" open " and " close ") in bank S of the sending switch. The circuit of CS may include a manual start key. SA pulls up over home contacts of the sending and receiving switches, and operates M and Y, Z to prepare the impulsing group X-Z of which X (slow-to-operate) impulses the line. SA also shorts the high resistance relay SK so that line relay L pulls up in series with relay LX in the common apparatus, Fig. 5, at the controlled station. Relay B pulls up and releases Z to start the impulsing and BX at the controlled station operates YX of the impulsing group, XX-ZX, ZX and VX being left normally operated in series at the termination of control or supervisory operation as will be seen later. The sending switch S and distant receiving switch RX are now synchronously stepped by relay X until S arrives at the contact marked in S1, when Z is held in series SS which prepares a stepping circuit for the receiving switch at the controlling station. At the controlled station, CX operated in parallel with magnet RX during impulsing to hold VX, ZX when RX moved off normal. CX now falls back, the group XX-ZX starts impulsing and relay XX synchronously steps SX at the controlled station and R at the controlling station until ZX holds in series with VX over SX1 circuit breaker contacts PI, and bank RX2. It will be seen that SX and R are positioned according to the condition of the circuit-breaker whereas S and RX are positioned in accordance with the condition the circuit breaker is desired to assume. At the controlling station, C operated during impulsing relapses and lights lamp SL, or one of a pair if two are used as shown, to indicate correct selection of the circuit breaker. One coil of the two position indicator D is also energized but is ineffective. The " operation " key K is now thrown to energize OD which releases M to extinguish lamp SL and reverses the line current to operate EX at the controlled station which holds the impulsing group and operates FX which energizes the " close " coil of the circuit breaker. Circuit-breaker contacts P1 change over to alter the marking in SX1 while contacts CW also wipe over a circuit but this is ineffective since FX is operated. The operator restores key K to release OP, EX, and impulsing at the controlled station recommences to step SX and R until SX arrives at the changed marking. At the controlling station C falls back and energizes the other coil of indicator D which thereupon changes over, and lights lamp ML which the operator extinguishes by reversing MR. An alarm may be used in addition to ML. Key TW is now restored to normal to release CS, SS and Z. The controlling station starts impulsing and S, RX step home where Z again holds over SS, S1 (normal) R3 (off normal), S3 (normal). Relay CX operated during impulsing to hold the group XX-ZX at the controlled station relapses, the group impulses, and SX, R go home where ZX, VX hold over normal positions of SX1, RX2. At the controlling station, SA is now short-circuited, removes the short circuit on SK and all apparatus is normal. Signalling changes from controlled station. Assuming circuit breaker, Fig. 6, trips out, contact CW momentarily operates AX, DX follows, releases AX and falls back slowly. The momentary break of the line by DX releases SK at the controlling station so that CK and SA pull up and the latter locks up. Relays X-Z impulse as before and S, RX advance until Z holds over SS S1, R2 and a contact of CK. Whenever an item of major importance at the controlled station changes over, the condition of the whole of such items is checked, these items are represented by cross-connections between S1 and R2 and circuit breaker, Fig. 6, is the first of these. On cessation of impulsing, impulses are sent as previously described from the controlled station indicative of the position of the circuit breaker. The indicator D operates, as will be understood from previous description, if the circuit breaker has changed position. During the impulsing from the controlled station, relay group at the controlling station was held by C. This relay now falls back and impulsing proceeds until S1 reaches the contact cross-connected to the group (2) on which R2 was left standing. The supervisory impulses from the controlled station then step R2 on to a position in a new group indicative of the position of the next item at the controlled station. Although the tap-changing switch, Fig to be described later, it not as shown arranged as an item of major importance, it could be arranged that wiper NX, when moving as the result of a tap change, could give a start signal similar to the momentary signal over CW in the case of the circuit breaker. Meter readings. To obtain a reading of the supply 52, Fig. 7, the operator at the control station throws key SW, Fig. 3, of equipment individual to the controlled apparatus shown in Fig. 7. Relay CS operates and switches S, RX step as before until S1 reaches the contact marked by SW. Switches SX and R are positioned as before and lamp ML lights if the selection is correct, the switches being all on contact 4. The read key RK is momentarily thrown to operate OP which releases M and reverses the line current to energize EX so that HX, Fig. 7, pulls up, locks and connects the supply to a power driven transmitter which is set in accordance with the supply. There is now an effective connection between contact 4 of RX2 over the contacts of TX to bank SX1 which is thus provided with a new marking to which SX is stepped while EX relapses to start the impulsing group XX-ZX. R, Fig. 1, steps in synchronism, and when C relapses at the end of the train, the unlocking coil LE of meter ME is energized and the meter reads in accordance with the setting of the potentiometer bank R4. All the meters are connected in series, but only ME is unlocked. Switches SX and R follow the movements of TX, Fig. 7, so long as key SW is thrown so that continuous observation is provided. Tap changing. Indicator key N1, Fig. 4, is first thrown to operate CS and mark S1 whereupon the two pairs of switches step as before to a position corresponding to the apparatus selected. The momentary throwing of SH operates OP, EX and also SX, Fig. 5, at the tap changer represented by switch NX. Contacts j<x> change the marking in SX1 to a position dependent on the wiper of NX, switches SX and R re-position themselves and the position of NX is signalled to meter TP over the potentiometer bank R4. Key N1 in the control apparatus is returned to normal, but if it is desired to change the position of the tap, AR is thrown and N1 is subsequently released. This changes the marking in S1 and all the switches are re-set so that RX is standing on 67 and other switches correspond. Lamp RA lights up. JX has now relapsed. Key RL is then thrown to operate OP, EX and the " raise relay MX which closes a circuit to drive NX one step up. JX also re-operates in series with MX and the synchronous switches position themselves in accordance with the new setting of NX which is then indicated on meter TP. Further upward steps may be made by repeated operation of key RL with key AR thrown. Stepping down is correspondingly effected by key OL and relay KX, Fig