US1638880A - Automatic reclosing-circuit interrupter - Google Patents

Description

1,638,880 1927- E. REAGAN I AUTOMATIC RECLOSING CIRCUIT'INTERHUPTER Filed NOV. 20, 1923 A Erin/ha! Va/fage INV'ENTOR WITNESSES: Maurlce E. Reag n- Patented Aug. 16, 1 927.

UNITED STATES PATENT OFFICE.

MAURICE E REAGAN, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, CORPORATION OF PENNSYL- VANIA.

AUTOMATIC RECLOSING-CIRCUIT INTERRUPTER.

Application filed November 20, 1923. Serial No. 675,834.

My invention relates to electrical transmission systems and particularly to reclosing circuit interrupters therefor.

One object of my invention is to provide areclosing circuit interrupter that shall operate in accordance with the characteristic curve of a shunt-wound direct-current generator.

Another object of my invention is to pro'-' vide a reclosing circuit interrupter that shall operate in accordance with the eflectof the resistance of a detached section of a transmission line upon a shunt-wound directcurrent generator.

It is also an object of my invention to provide a reclosing-circuit-interrupter system having a plurality of dynamo-electric machines for selective operation, either as a motor or as generator, during the reclosing operation of a circuit interrupter, in accordance with the resistance 01. that portion of a transmission line that is detached from the main line and which it is desired to connect to the main transmission line.

In the prior art, reclosing circuit interrupters have been operated to reclose by devices responsive to the direct measurement of the potential drop, as indicative of the resistance in a detached portion 01" a transmission line, such as by a lVheatstone bridge. But, so far as I know, I am the first to utilize the characteristics of a shunt-wound direct-current generator in combination with the resistance of a detached section of a transmission line for controlling the connection of a detached section to the main transmission line. i l

It is a well known fact that the terminal voltage Off a shunt-wound direct-current gencircuit therewith and that, if the resistance in the circuit remains abnormally low, it is impossible to increase the terminal voltage erator is dependent upon the resistance in age in. a shunt-wound direct-current generator in order to operate suitable devices for controlling a circuit interrupter in the detached section of the transmission line.

In the accompanying drawings,

Figure 1 is a diagrammatic view of apparatus and circuits embodying my inven tion, as applied to a sectionalizing switch for connecting two sections of a transmission line. i

Fig. 2 is a. diagrammatic view of apparatus and circuits embodyingmy invention, as applied to a reclosing circuit interrupter for connecting a distributing feeder to a main-transmission line.

Fig; 3 is 'a curve illustrating teristic of a shunt-wound, direct-current generator.

In the several figures of the drawing,

similar reference numerals indicate like parts.

In the embodiment of my invention shown in Fig.1, a direct-current transmission line comprises the sections 1 and 2 that are separated by a sectionalizing insulator 3 and a grounded conductor 5 that may be in the form of a railroad rail. A circuit interrupter l is connected around the section insulator 3, and the operating coil of an overload relay 6 for the interrupter is placed in circuit with either of the sections 1 and 2.

The circuit interrupter 4 comprises a pair of main stationary contact members 7 and auxillary contact members 8 and 9, an operating coil 11 and an armature member 12 that carries a main bridging contact memauxiliary bridging members 8 and 9 are adapted for controlling auxiliary circuits hereinafter described.

A pair of dynamo- electric machines 17 and 18 are mechanically connected, as at 19, and have one of their terminals connected to the h m s ste med cond t r he the characdynamo- electric machines 17 and 18 are provided, respectively, with shunt-connected field windings 21 and 22, that are connected in parallel with the operating coils 23 and 24 of the auxiliary switches 25 and 26, respectively.

The auxiliary switch 25 is provided with bridging contact members 27, 28 and 29 Which co-operate with the pairs of stationary contact members 31, 32 and 33, respectively. The auxiliary switch 26 comprises bridging contact members 34, 35 and 36, which co-operate with the pairs of stationary contact members 37, 38 and 39, respectively.

Another auxiliary switch 41 is associated with the auxiliary switch 25 and comprises an operating coil 42 and bridging contact members 43, 44 and 45, the latter co-operating with the pairs of stationary contact members 46, 47 and 48, respectively. A resistor 49 is connected'in circuit with one terminal. of the operating coil 42, and the other terminal thereofis connected to one of the stationary contact members 33 and 48.

A similar auxiliary switch 51 co-operates with the auxiliary switch 26 and comprises an operating coil 52 and bridging contact members 53 and 54 which co-operate with the pairs of stationary contact members 56, 57 and 58, respectively. A resistor 59 is connected to one terminal of the operating coil 52, and the other terminal of the coil 52 is connected to one of the stationary contact members 39 and 58.

A resistor 61 is connected in circuit between one of the stationary contact members 8 and a terminal 62 of the dynamo-electric machine 18. The bridging contact member 27 and the pair of stationary contact members 31 are adapted to form a short-circuit around the resistor 61, under conditions hereinafter described. A resistor 63 is connected to one of the stationary contact memhers 9 and the terminal 64 of the dynamoelectric machine 17. The resistor 63 is adapted to be short-circuited by the bridging contact member 34 and the pair of stationary contact members 37, under conditions to be hereinafter described. A resistor 66 is placed in circuit with the switches 41 and 51.

The overload relay 6 is adapted to operate auxiliary pilot switches 71 and 72 which are in circuit with the holding coils 42 and 52 of the switches 41 and 51, respectively. The switches 71 and72 may be associated with the overload relay 6 by any mechanical means, although I have shown them as attacheddirectly to the bridging member 16.

The embodiment of my invention shownin Fig. 1, is intended to be usedas a sectionalizing switch. In the drawing, it is assumed that the section 2 of the transmission line has been unduly loaded, either by excessive power demands or by a shortcircuit, and the circuit interrupter 4 has been operated, either by the action of the overload relay 6 or by the inability of the operating coil 11 to keep the circuitinterrupter 4 in its closed position by reason of a voltage drop accompanying the excessive power demand.

The circuit interrupter 4, in moving to its open position, separates the bridging contact member 13 from the pair of stationary contact members 7, thereby disconnecting the section 2 of the transmission line from the section 1. Simultaneously, circuits are completed between the bridging contact members 14 and 15, and the pairs of stationary contact members 8 and 9, respectively. One of these circuits extends from the section 1 of the transmission line through the stationary contact member 9 and the bridging contact member 15, the resistor 63 and the terminal 64 of the dynamo-electric machine 17, to the grounded conductor 5. The second circuit extends from the section 2 of the transmission line, through the bridging contact member 14, the stationary contact members 8, the resistor 61 and the terminal 62 of the dynamo-electric machine 18, to the grounded conductor 5.

It is to be observed that, during the opera ing movement of the circuit interrupter 4, a circuit is completed from each of the sections 1 and 2 to one of the dynamo-electric machines 1.7 and 18.

By virtue of these connections, the dynamo-electric machine that is connected to that portion of the transmission line which is Still energized is caused to operate as a motor, while the dynamo-electric machine which is connected to the detached or de-energized portion of the transmission line initially remains electrically inactive. It will thus be seen that, whichever part of the transmission line is (lo-energized, the one or the other of the dynamo- electric machines 17 and 18 will be selectively called upon to act as a motor that is energized from the energized section of the transmission line.

In Fig. 1, the dynamo-electric machine 17 is shown as a motor, the field coil 21 thereof being energized from the section 1 of the transmission line. If the section 1 of the transmission line had been detached and the section 2 had remainedenergized. the dynamo-electric machine 18 would have been called upon to act as a motor.

By virtue of the mechanical connection 19 between the dynamo- electric machines 17 and 18, the one that is operated as a motor drives the other as a generator.

The characteristic curve of a shunt-wound direct-current generator is shown in Fig. 3. where the point A indicates the value of voltage generated, with no load on the generator armature and the point B indicates 'the bridging contact member 27.

the maximum load on the which saturation results.

It the voltage at the terminals of the generator decreases, because of armature reactance and armature resistance, the field current also decreases and causes a further decrease in the number of lines of flux in the generator, and, therefore, the terminal voltage of the shunt-wound generator becomes less than it would be it the machine were separately excited. This condition continues until the current in the generator decreases to a point at which it. is not sufficient to generate more than enough flux to overcome the resistance drop in the armature, and the voltage thereon reaches a zero value, as indicated by point C. y

The generator .18 supplies current to a circuit comprising the field-magnet winding 22, the operating coil. 24 of the switch 26, and a circuit extending from the terminal 62 to the resistor 61, the stationary contact mem generator beyond bers 8 and the bridging contact. member 1.4,

the sect-ion 2 of the transmission line and the attached load or short-circuit (not shown) to the return conductor 5. As soon as the voltage of the generator 18 exceeds a predetermined value, the operating coil 24 operates to close the switch 26, However, it the resistance of that port-ion of the parallel circuit comprising the section 2 and the load or short-circuit is very low the current will be very large, and the voltage generated will not be su'l'iicient to operate the switch 26.

In the mean time, the voltage of the circuit from the motor 17 to the operating coil 23 of the switch 25 increases in proportion to the speed of the motor, and a point is reached at which the operating coil 23 closes the switch 25. The operation of the switch 25 short-circuits the resistor 61 through the pair of stationary contact members. 31 and I The operation of the switch 25 also completes the circuit to the operating coil 42 of the switch 41 extending from the section 1 to the resistor 49, the operating coil 42, the pair of stationary contact members 33, the bridging,

contact member 29 and the conductor 5.

Vith the operation of the switch 41, an incomplete circuit may be traced from the section 1 of the transmission line, through the pair of stationary contact members 46, the bridging contact member 43, the pair of stationary contact members 47, the front contact member 44, the bridging member 16 of the relay 6 and the operating coil 11 of the circuit interrupter 4. to the stationary contact member 57, at which point the cir= cuit is open. With the short-circuiting oi the resistor 61 from the circuit of the gen-I erator 18, the resistance of the section 2 and its load or attendant short-circuit is directly impressed; upon the generator. 18.

-Accordingly, the strength and amount of the current delivered by the generator 18 is determined by the resistance of the detached section 2.

As the resistance in the detached section 2 of the transmission line increases, by reason of the removal of the power load or to the clearance of the short-circuit, as the case may be, the voltage of the generator 18 is sufficient to operate the coil 24 ot' the switch 26 to close the same.

The operation of the switch 26 closes the incomplete circuit ref-erred to above which extends from the section 1 through the pair of stationary contact members 46, and the contact member 43, the pair of stat onary contact members 38. and the contact member 35, the resistor 59, the operating coil 52 of the switch 51, through the stationary contact members 39 and the contact member 36, to the grounded conductor 5. The completion of this circuit causes the auxiliary switch 51 to be operated, whereupon the circuit of the operating coil 11 of the circuit interrupter 4, heretofore traced, is completed through the pair of stationary contact members 57, the contact member 54 and the grounded conductor 5,

The completion of the circuit through the operating coil 11 of thecircuit interrupter 4, closes the same, and the sections 1 and 2 of the transmission line are connected together through the bridging contact member 4 and the stationary contact members 7. The closing of the circuit interrupter 4 inter rupts the circuit between the bridging con tact members 14 and 15 and the stationary contact members 8 and 9, respectively, which interrupts the circuit to the motor 17 and the generator 18.

The circuit interrupter 4 is held in its closed position by reason of the circuits conipleted. through the bridging contact member -and the stationary contact; members 48 of .the switch 41 and the bridging contact iember 55 and the stationary contact members 58 of the switch 42, thereby maintaining the operating coils 42 and 52in their energized positions, respectively. The op erating coils 42 and 52 are deenergized only by low Voltage in the system, or by theinterruption of the circuits therethrough by the overload relay 6 and the associated switches 71 and 72.

In theevent that section 10f the transmission line is detached from section 2, the sequence of operation of the switches be comes switch 26, switch 51, switch 25 and switch 41, while, in the condition above described, the sequence of operation of the switches is switch 23, switch 41, switch 26 and switch 51.

It will thus be seen that I have provided by a series of auxiliary switches and operatingcoils that are responsive to the voltage of the generator.

In Fig. 2, I have shown my invention applied to a feeder circuit 101 that is supplied with energy from agenerator 104 through a main conductor 102 and a return grounded conductor 103. The feeder circuit 101 is provided with a circuit interrupter 105. A plurality of dynamo- electric machines 17 and 18, having shunt field- magnet coils 21 and 22, respectively, are connected by mechanical means 19 in the manner shown in Fig. 1.

An overload relay 106, comprising an operating coil 107, a pair of stationary contact members 108 and a bridging member 109, is connected in circuit with the feeder circuit 101. An auxiliary switch 11 comprises an operating coil 112, a pair of stationary contact members 113 and a bridging member 114. A resistor 115 is placed in circuit with the dynamo-electric machine 17 which, in this form of my invention, always operates as a motor, while the machine 18 always operates as a generator.

The switch 105 comprises an operating coil 116 pairs of stationary contact members 117, 118, 119 and 121, the latter being in connection with the bridging member 125, the main contact members of the switch. The auxiliary bridging members 122, 123 and 124 co-operate with stationary contact members 117, 118 and 119, respectively.

Assuming the circuit interrupter 105 to be in its open-circuit position, as shown in Fig. 2, a circuit is completed extending from the main conductor 102, through the stationary contact members 117, the bridging contact member 122, the resistor 115 and the dynamo-electric machine 17, to the grounded conductor 103, whereupon the machine 17 becomes energized as a motor to drive the machine 18 as a generator.

The generator 18 has a shunt field-magnet winding 22 and the operating coil 112 of the auxiliary switch 111 is connected across the terminals of the generator 18, and one terminal of the generator is connected in series with the conductor 101 through the contact members 118 and 119 of the switch 105. The resistance of this circuit controls the buildingup of the voltage of the generator and, when the voltage reaches a sufi'iciently high value, by reason of the load on the circuit 101 being low, the switch 111 will be closed,

and a circuit will be established to extend from the conductor 102, through the 0 erating coil 116, stationary contact mem ers 113 and bridging member 114, to the grounded conductor 103.

The circuit interrupter 105 is thereupon actuated to its closed position, and the feeder conductor 101 is connected to the main conductor 102 through the stationary contact member 121 and the bridging contact member 125. At the same time, a circuit .is completed from the conductor 102, through the operating coil 116, the stationary contact member 119, the contact member 124, the stationary contact member 108, and the bridging member 109, to the grounded conductor 103.

The completed circuit so energizes the operating coil 116 that the circuit interrupter 105 is held in its closed position. Simultaneously, the circuits between the contact members 122 and 123 and the stationary contact members 117 and 118, respectively, are interrupted, and the motor 17 and the generator 18 are disconnected from the circuit. The switch 111-thereupon returns to its de-energized position.

In the event that an overload occurs in the feeder conductor 101, the overload relay 106 is actuated, thereby interrupting the circuit to the operating coil 116, whereupon the circuit interrupter 105 returns to its open position under the influence of the force of gravity. In the event that the voltage across the conductors 101 and 102 falls below a predetermined value, by reason of overload or short-circuit conditions, the operating coil 116, being unable to maintain the circuit interrupter 105 in its closed position, the latter opens under the influence of the force of gravity.

The operation of the circuit interrupter 105, under either of these conditions, connects the motor 17 in circuit with the conductor 102, whereupon the above described cycle of operations is again completed.

The operation of this form of my invention differs from that shown in Fig. 1 only in its application as an automatic reclosing circuit breaker for connecting a feeder circuit to a supply circuit, while the form of my, invention shown in Fig. 2 is adapted for use as a sectionalizing switch to connect different sections of the same transmission line. In both forms of my invention, the resistance of the detached conductor is employed for controlling the building up of the voltage of a shunt-Wound direct-current generator to such value that the voltage may be used to control a circuit interrupter for connecting the sections of the transmission line together.

The low resistance incidental to an overload or a short-circuit, when connected to terminals of the shunt-wound direct-current generator, precludes the generator from genlimitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. In combination, a direct-current transmission line having a plurality of sections, a circuit interrupter for connecting certain of said sections, a plurality of dynamo-electric machines, means controlled by said circuit interrupter when in its open position whereby one of said dynamo-electric machines is caused to operate as a motor and another of said machines is caused to operate as a generator in accordance with the section of said transmission line that is deenergized by the opening of said circuit interrupter.

2. The combination with an electrical transmission system comprising two circuit sections and a circuit interrupter connected therebetween, of means for controlling the operation of said circuit interrupter comprising two mechanically connected dynamoelectric machines respectively associated with the said circuit sections and each adapted to operate either as a motor or as a generator, and means co-operating with each of said dynamo-electric machines to respond to a predetermined condition of the associated circuit section.

3. The combination with an electrical transmission system comprising two circuit sections and a circuit interrupter connected therebetween, of means for controlling the operation of said circuit interrupter comprising two mechanically connected dynamoelectric machines respectively associated with the said circuit sections and each adapted to operate either as a motor or as a generator, and a voltage-responsive device cooperating with each of said dynamo-electric machines to respond to a predetermined .condition of the associated circuit section.

4. The combination with an electrical transmission system comprising two circuit sections and a circuit interrupter connected therebetween, of means for controlling the operation of said circuit interrupter comprising two mechanically connected dynamoelectric machines respectively associated with the said circuit sections and each adapted to operate either as a motor or as a generator having a drooping currentvoltage characteristic, and a voltage-responsive device co-operating with each of said dynamo-electric machines to respond to a predetermined condition of the associated circuit section.

5. The combination with an electrical transmission system comprising two circuit sections and a circuit interrupter connected therebetween, of means for controlling the operation of said circuit interrupter com,- prising two mechanically conmnected dynamo-electric machines respectively associated with the said circuit sections and each Y .adapted to operate either as a motor or as a generator having substantially the current-voltage characteristic of a shunt-wound direct-current generator, and a voltage-responsive device cooperating with each of said dynamo-electric machines to respond to a predetermined condition of the associated circuit section.

6. The combination with an electrical transmission system comprising two circuit sections and a circuit interrupter connected therebetween, of means for controlling the operation of said circuit interrupter comprising two mechanically connected dynamo-electric machines, means controlled by the circuit interrupter for connecting the dynamo-electric machines respectively .to the two circuit sections in such manner that, when either of the circuit sections is energized and the other is de-energized, the machine that is connected to the energized sec tion operates as a motor to drive the other machine as a generator to impress voltage upon the de-energized section, and means responsive to the voltage so impressed upon the de-energized section.

In testimony whereof, I have hereunto subscribed my name this 14th day of November 1923.

MAURICE E. REAGAN.

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