Patent GB-258178-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: 1925-06-12
Abstract: 258,178. Automatic Telephone Manufacturing Co., Ltd., and Remington, C. June 12, 1925. Selective distant-control systems ; tell-tale apparatus.-In a system for supervising and controlling from a remote point, the operation and condition of apparatus units at a substation, each time an apparatus unit e.g. a circuit breaker changes its position, the circuit of a relay is closed to initiate the transmission of a supervisory signal to the transmitting station and is opened at the commencement of the transmission so that. it may be re-energized to iritiate a second signal at the conclusion of the first, in the event of a second unit changing its position during the transmission of the first signal. Means are also provided to ensure that should a unit change its position twice in rapid succession, signals of both conditions are transmitted. The apparatus units of the substation are selected by a constant number of impulses which are transmitted under the control of a step-bv-step switch at the control station. The selection is determined by the position on the impulse train of an impulse of distinctive character and is checked at the control station prior to the operation of the selected unit. The supervisory signals of the condition of the apparatus are transmitted to the control station by a step-by-step switch, the contacts of which are marked in accordance with the positions of the units. Thus when a supervisory operation is initiated a train of impulses which is characteristic of the positions of all the units is transmitted. The impulses operate a step-by-step switch at the control station, the contacts of the switch being associated with the supervisory lamps. The selecting and supervisory signals are transmitted over two line wires. After selection a circuit for operating the selected unit is prepared over a third line. Fig. 3 shows the supervisory signal transmitting apparatus at the substation. Associated with each circuit breaker is a contact such as CB2 and a group of relays such as OR2, ORB, IR2. When a unit changes its position either automatically or under the control of the operator at the control office a relay OR2 is energized or de-energized according to the final position of the unit to connect or disconnect battery from the corresponding contact of the step-by-step switch RLS5. The relay OR2 also energizes the relay QR5 over a circuit which is opened after an interval by the operation of relays ORB, IR2 but the relay QR5 locks up over the wiper W5D and operates a relay SR5. The relay SR5 causes the step-bystep rotation of the switch RLS5 which transmits a train of impulses over the lines which is ' characteristic of the positions of all the circuit breakers. The locking circuit of the relav SR5 is opened at the first step of the wiper W5D so that if another circuit breaker opens during the signalling operation, the relay is again energized and locked up over the wiper W5D to again initiate the supervisory operations after the completion of the first complete operation of the switch RLSS. Fig. 5 shows a modification wherein tEe three relays, Fig. 3, individual to each circuit breaker are replaced by brushes operated by the breakers. The circuit breakers control brushes BA1, BA2, BA3, which cooperate with contacts SA1, SB1, SC1; SA2, SB2, SC2; and SA3, SB3, SC3 respectively. When a circuit breaker changes its position a circuit is momentarily completed between contacts such as SB1, SC1, for the relay QR5 and the supervisory signalling operation is initiated in the manner previously described. The contacts such as SA1 are used for making the contacts of the rotary transmitting switch. The apparatus also makes provision for notifying the dispatcher of the closure of a circuit breaker even if it should open immediately afterwards due to an overload. For this purpose relays RR1, RR2, RR3 are associated with the circuit breakers. In the apparatus shown in Fig. 3 an additional relay for each circuit breaker is necessary. When a circuit breaker is closed, a relay, such as RR1, is energized over the contacts SB1, SA1 and locks up. An indication of the " closed " position is transmitted to the control station in the manner previously described. The relay RR1, however, operates the relay AR1 which energizes a slowacting relay SAR1 and thereby prepares circuits to contacts SC1, SC2, SC3. When the stepping switch reaches its normal position, the relay RR1 is de-energized to open the circuit of the relay AR1 and thereby cause a second operation of the relay QR5. The relay QR5; causes the switch RLS5 to make a second revolution and transmit the indication of any changed conditions. The system described is identical with that described in Specifications 252,230, 252,231, 258,012, and 258,179 which are referred to.