Patent GB-263099-A (GB)
Title: Improvements in electrical supervisory control systems
IPC: H02J13/00
Filed: 1926-10-26
Abstract: 263,099. Metropolitan-Vickers Electrical Co., Ltd., (Assignees of White, T. U.). Dec. 17, 1925, [Convention date]. Selective distant control systems; tell-tale apparatus.-In a system for supervising and controlling from a remote point, the condition and operation of apparatus units, such as circuit breakers, at. a substation, the units are successively associated with corresponding control keys and supervisory lamps over common control and signalling lines, by synchronously driven step-bystep selector switches at each station. Fig. 1 shows the apparatus at the control stations and Fig. 2, the substation apparatus. The circuit breaker, such as B, and the corresponding control keys eg. K<1> are respectively associated by the wipers of the bank contacts C<1>, C<2> of rotary switches with the common control line c. The supervisory signals such as S91, S92 associated with each unit are operated over the line s through the bank contacts S<1>, S<2> of the rotary switches. The switch at the control station is driven stepby-step by two groups of relays 14, 15, 16 and 17, 18, 19 and that at the substation by the groups of relays 217, 218, 219 and 220, 221, 222. These groups are alternately operated over the bank contacts D<1>, D<2> and the common line d by impulses of opposite polarity to operate the stepping electromagnets 9, 216. This arrangement ensures the correct operation of the switches at each station for if the switches are out of step, the proper control relays at one station are not associated with the corresponding control relays at the other station and in consequence, the stepping electromagnets are not operated and the selecting operation is held up. The operation of the selecting switches is initiated by a " start " key K<10>. When the switches engage the contacts associated with the operated key the. desired operation is effected and the appropriate supervisory signal is transmitted back to the control office. A key such as KS<2> is also associated with each unit to enable the operator to stop the switches in the corresponding selecting positions and thereby remain in connection with the selected apparatus. By depressing the apparatus key indications of the voltage across the line at the substation may be given on a meter 51. The voltage is transformed into current variations, which are transmitted over the line c, by a. Kelvin balance 260 and a resistance 274. Normal condition of apparatus. When the apparatus is inoperative, a relay 4, Fig. 1, is energized in series with a relay 210. Fig. 2, over the first contacts on the banks C', C<2> of the rotary stepping switches and the line c. Operation of circuit breaker. The appropriate control key is operated in a direction depending upon the operation to be effected and the "start" key 10 is moved to close its upper contacts. The key K<10> energizes a relav 6 which closes a series circuit over the relays 5, 6. This circuit has no effect so long as the relay 5 is short-circuited by the key K<10>. When this key is released the relay 5 opens the series circuit over the normally energized relays 4, 210. De-energization of the relay 4 opens the circuit of the relay 7 and in consequence the relay 12 is de-energized to prepare the driving circuit for the switches over the line d. Similarly at the substation de-energization of the relay 210 opens the circuit of the relay 224 and the driving circuit is completed from positive battery at the sub-station relay 217, switch D<2>, line d, switch D<1>, relay 14 to negative battery. The relays 14, 217 energize the stepping magnets 9, 216 and the relays 16, 219 which prepare the energizing circuit of the relays 15, 218. The stepping magnet 9 operates a relay 10 which opens the driving circuit at the armature 26 to release the relays 14, 217. Upon release, the relays 15, 218 are energized to open the circuits of the magnets 9, 216 and permit the selector switches at each station to move one step. When the switch at the control station occupies its initial position a relay 13 is energized over a resistance 33, but when the switch is operated, this relay is short-circuited over the first contact in the group B' and in consequence a relay 11 opens the locking circuit of the relay 10 to again close the driving circuit. Since, however, the switches at each station now engage the second contacts in the groups C', C<2>, the relays 17, 220 are energized in series over the line d from positive battery at the control station to negative battery at the substation. The relays 17, 220 energize the stepping magnets 9, 216, the former of which operates the relay 10 to again open the line circuit d and cause the switches to move through a second step. The control relays 14, 217 are connected to odd contacts, in the bank D<1> and the relays 17, 220 to even contacts so that during rotation of the switches the relays at each station are alternately connected in series. Each set of control relays is energized by impulses of opposite polarity to ensure that in the event of disagreement of the position of the wipers of the banks D<1>, D<2>, no current flows in the driving circuit and the operation is stopped when the wiper of the contacts C' arrives. At the contact marked by the operated control key a circuit is completed over the control wire c for operating the associated apparatus unit. If, for example, it is desired to close the circuit breaker 13 a circuit is established over the master key MC, key K<1>, second contact in the bank c', line c, second contact in the bank C<2> and relay 201. The relay 201 operates a relay 204 which energizes the closing coil of the circuit breaker. The connection between a control key and an apparatus unit may be maintained since by opening the contacts of the corresponding " stop " key, such as KS<22>, the relay 13 is still maintained energized when the wiper of the bank B<1> steps on to the appropriate contact, and in consequence the relay 10 is held locked to open the line circuit d and thus prevent further stepping of the selector switches until the " stop " key is restored. Supervisory signalling. When the circuit breaker closes, the relay 209 is de-energized to open two circuits of the relays 208, 207 and thereby complete a circuit over a contact on the bank S<2>, line s, contact in bank S<1> and relay 46 to operate the indicator S". The indicator operates a relay 48 to prepare the circuit of the indicator S<92> associated with the " open condition of the circuit breaker. Signalling automatic operation of circuit breaker. Upon automatic operation of the circuit breaker, a relay 211 is energized to open the normally closed circuit over the relays 4, 210 to initiate the stepping operation in the manner previously described. The Specification as open to inspection under Sect. 91 (3) (a) states that the system may be applied to telephony, telegraphy, fire alarms sys. tems, railway signalling and street lighting. This subject-matter does not appear in the Specification as accepted.