US1689515A - Automatic reclosing-circuit-breaker system - Google Patents

Description

Oct. 30, 1928. 1,689,515

A. EPANDERSON AUTOHATIG RECLOSING CIRCUIT BREAKER SYSTEM Original Filed Feb. 26. 1926 I. Fig.2.

lnvntof: vArm/id E.. Anderson,

His, Attovney Patented Oct. 30, 1928.

UNITED STATES PATENT OFFICE.

ARVID E. ANDERSON, OF SCOTIA, NEW YORK, ASSIGN OR TO GENERAL ELECTRIC COM- PANY, A CORPORATION OF NEW YORK.

AUTOMATIC REOLOSING-CIRCUIT-BREAKER SYSTEM.

Application filed February 26, 1926, Serial No. 90,950. Renewed June 29, 1928.

My invention relates to auton'iatic reclos-.

ing circuit breaker syslzei'ns and one ot'its objects is to'provide an nnproved system for automatically reclosing a circuit breaker between a supply and a load circuit when the supply circuit is energized and the load connected to the load circuit is less than a predetermined value.

Another object is to provide an improved system which will automatically reclose the circuit breaker between two circuits whenever either circuit is energized and the load connected to the other circuit is less than a predetermined value.

My invention will be better understood from the following dcscriptionwhen taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

In the accompanying drawing, Fig. 1 is a diagram of an automatic reciosing circuit breaker system embodying my invention, and Fig. 2 is a modificationoit a portion of the system shown in Fig. 1..

Referring to Fig. l of the drawing, 1 and 2 represent conductors of two electric circuits which are arranged to be connected together by a circuit breaker 3 which may be of any suitable type, examples of which are well known in the art. In order to simplify the disclosure, it is assumed that the ground constitutes the other side of the two circuits. It will be obvious, however, that my invention is not limited to a grounded system, but is applicable also to systems in which metal lic conductors are used entirely for conducting the current therein.

As shown in the drawing, the circuit breaker 3 is the well-known cont actor type which has a closing coil a. This coil, when energized, closes and maintains the circuit breaker closed. The circuit of the closing coil controlled by an overload relay 5 which is connected so as to open the circuit of the closing coil 4 when an excessive current flows through the main contacts of the circuit breaker from one circuit to the other.

When the circuit breaker is opened due to an overload or fault on one of the circuits it is desirable to reclose the circuit breaker as soon as the overload or fault has been ren'ioved. For accomplishing this result, 1 provide an arrangement whereby a limited current is periodically supplied from the normal circuit to the overload-ed or faulty circuit and the reclosing of the circuit breaker is controlled in response to the amount of current that flows from the normal circuit to the overloaded or faulty circuit.

7 represents an impedance, shown as a resistor, which is periodicallyconnected between the conductors 1 and 2 for a certain length of time by suitable automatic switching means 8, shown as electroresponsive switching means, when the circuit breaker 3 is open. The periodic closing and opening of the switching means 8 is effected by the time element control relays 9 and 10. y The relay 9 is arranged to be energized when both the circuit breaker 3 and the switch 8 are opened, and after a predetermined time effects the energization of relay 10. The relay 10 immediately closes its contacts and effects the energization of the closing coil 11 of the switching means 8 so that the resistor 7 is connected between the conductors 1 and 2. The circuit of the relay 10 is also controlled by the switching means 8 so that when the switching means closes, it effects the deenergization of both of the relays 9 and 10. The relay 9 immediately opens its cont-acts but the relay 10 is designed so that it does not open its contacts until after the coil of the relay 10 has been deenergized for a certain length of time. Consequently the switching means 8 remains closed for a predetermined length of time. controls the circuit of another time element relay 12 which, after its coil has been energized a certain length of time, completes an energizing circuit for the closing coil 4 of the circuit breaker 8. The time element of the relay 12, however, is such that the relay is not energized for a sufiicient length of time to close its contacts so long as the overload or fault remains connected to the overload or fault circuit. As soon as the relay 10 opens its contacts the relay 12 is deenergized and it immediately returns to its deenergized position. The closing coil 11 is also deenergized by the opening of relay 10 so that the switching means 8 opens. As soon as the switching means 8 opens the control relay 9 is again energized and the above cycle of operation is repeated. It will be observed, therefore, that when the circuit breaker 3 is in its open position, means is provided whereby the resistor 7 is periodically connected between the two conductors for a predeter- Ih ih ed length of time. Since the resistor is The control relay 10 also in circuit for only a short time, much smaller and cheaper resistor can be used than would be required if it were in circuit con tinuously. This is a very importantadvantage, especially in high voltage systen'is or systems in which a large load-indicating current has to be used.

In order to clfect the reclosing of the circuit breaker 3 when the overload or fault is removed, I provide two reclosing relays 13 and 14: which are connected and arranged so that one of them will effect the closing of the circuit breaker when the fault or overload is on one of the circuits, and the other relay will eft'ect the closing of the circuit breaker when the fault or overload is on the other circuit. As shown in the drawing, relay 13 effects the closing of the circuit breaker 3 when the fault between conduc tor 2 and ground and conductor 1. and ground constitute the supply circuit and relay 1st effect the closing of the circuit breaker 3 when the fault is between conductor 1 and ground and conductor and ground constitute the supply circuit.

The relays 13 and 1 1 are shown balance differential relays. Each relay is arranged to complete a circuit for the relay 10 when the circuit breaker 3 is open and the switch ing means 8 is closed. The relays 13 and 1 1 are provided respectively with restraining windings 15 and 15 which are connected in series with each other in shunt around the main contacts of the circuit breaker 3, and operating windings 17 and 18. The operating winding 17 is arranged to be connected between the conductor 1 and ground and the operating winding 18 is arranged to be connected between the conductor and ground by means of a control relay 19 which is energized in response to the closing of the switching means 8. 'llherefore it will be observed that the restraining windings 15 and 16 are energized before the operating windings 1'? and 18 are energized so to insure that the contacts of the relays 13 and 1 1- are opened before the operating windings are energized.

One advantage in using balanced relays connected in the manner shown is that the relays automatically compensate for variations in supply voltage so that they respond to substantially the same impedance irrespectively of the supply voltage. For example, if the supply voltage decreases so that the force exerted by the operating coil connected across the supply circuit decreases, it will be observed that it will take less current through the resistor 7 to prevent the reclosing relay from closing its contacts. Similarly, if the supply voltage increases it takes more current through the resistor to prevent the reclosing relay from closing.

The operation of the system shown in the drawing is as follows:

ll hen the circuit breaker 3 is closed, it is held closed by the closing coil 4 which is energized from the positive side of a suitable control source through the closing coil 4-, contacts 20 of the overload relay 5, antiiliary contacts 21 on the circuit breaker 8 to the negative side of the control source. l i hile It have shown a separate control source, any arrangement, examples of which are well-known in the art, may be used. whereby the control devices receive current from which-ever one of the two circuits is energized when the circuit breaker is open.

.Vhen the circuit breaker 3 is closed, the remainder of the control devices are in the positions shown in the drawing.

llhen an overload occurs on one of the circuits so that the overload relay 5 opens its contacts, the closing coil at is deenergized and the circuit breaker 3 opens. ing of the auxiliary contacts 22 on the circuit breaker 3 completes a circuit for the time element relay 9. This circuit is from the positive side of the control source, through contacts conductor 22), contacts 24. of the switching means 8, conductor 25, coil 26 of relay 9 to the negative side of the control circuit. After a predetermined time, relay 9 closes its contacts 2? and completes a circuit for the coil 28 of the relay 10 from the conductor 25. The relay 10 immediately closes its contacts 29 and connects the closcoil 11 and the coil 30 of the time element relay 12 across the control source. The switching means 8 closes immediately and connects the resistor 7 between the conductors 1 and As soon as the switching means 8 closes it. will 1 e observed that the restraining windings 15 and 1c are connected in para lel with the resistor 7 so that they are encrzed in accordance with the amount of curcut that flows through the resistor 7.

The closing of the contacts Q1 of the switching means 8 completes the circuit of the control relay 1.9, which in turn completes the circuits of the operating windings 17 and 18. The circuit of the control relay 19 is from the positive side of the control source through auxiliary contacts 22 on the circuit breaker 3, conductor 23, contacts 31, conductor 32, 0011 of the relay 19 to the negatlve side of the control source.

If the overload or fault still exists when the operating coils 17 and 18 are energized, suiticient current flows through the restraining windings 15 and 16 to prevent either reclosing relay from closing its contacts. consequent ly, the time element relays 9 and 10, whose circuits are opened at contacts 24 when the switching means 8 closes, open their contacts 27 and 29. The opening of contacts 29 effects the deen ergization of the relay 12 and the closing coil 11. As mentioned above, the relay 12 is so designed that under these conditions it is not energized long enough to close its conill] loo

tacts 34;. As soon as the contacts 31 open, relay 33 isdeenergized and this relay in turn opens thecircuits of the operating coils 17 and 18. The closing of the auxiliary contacts 24 again completes the above traced circuit for the coil 26 oi the time element relay 9 and the above described operation is repeated until the fault or overload is removed.

If the overload or fault has been removed at the time the operating coils 17 and 18 of the reclosing relays 13 and 1 1 respectively are energized by the operation of the relay 33, the amount of current that flows through the restraining winding of the reclosing relay, whose operating coil is connected across the supply circuit, is not su'l'licient to prevent its operating coil from closing its contacts. For example, if conductor 1 and ground are the supply circuits and conductor 2 and ground the load circuit, and the abnormal load has been removed from the load circuit, suhicient current does not flow through the restraining winding of the relay to prevent the operating winding 17, when energized, from closing the contacts 38. It conductor2 and ground are the supply circuit and conductor 1 and ground the load circuit, the energization of the operating coil 18 of the r-eclosing relay 14'; is suflicient to overpower the'restraining coil 16 and close the relay contacts 39 when the abnormal load condition has been removed. The closing of either contacts 38 or 39 completes a holding circuit for the time relay 10 so that this relay remains energized for a sufiicient length of time to allow the time element relay 12 to close its contacts 8st. The closing of either contacts 38 or 39 does not complete a holding circuit "for the time relay 9 because this re lay opens its contacts 27 immediately after the contacts 2d are opened, and before either the contacts 38 or 39 p are closed. The holding circuit of the relay 10 is from the positive side of the control source, through auxiliary con tacts 22 on the circuit breaker 3, conductor 23, contacts 31, conductor 32, contacts 38 or 39, conductor 40, coil 28 of relay 10 to the ne; ;ative side of the control source. 'lhc closing of the contacts 34 of the relay 12 completes the energizing circuit for the closing coil 41. from the positive side of the control source through the closing coil 1, overload relay contacts 20, which are again closed after the circuit break or opens, conductor 35, contacts 3 1 of relay 12, conductor 36, contacts 37 to the negative side of the control source.

As soon as the circuit breaker 3. closes it completes the heretofore described holding circuit for its closing coil 3 through'the auxiliary contacts 21. The opening'oit the auxiliary contacts 22 on the circuit breaker 3, when itcloses, opens the heretofore described cir cuits of the coil.33 of relay 19 and the coil 28 of relay 10. The deenergization of relay 19 opens the circuit of the operating coils of the relay and 14, and the deenergization of r lay 10 opens the circuits of the relay 12 and the closing coil 11. Therefore, the closing of the circuit breaker 3 restores all of the other control devices to the positions shown in the drawing.

In Fig. 2 I show a modification of the portion of the system shown in Fig. 1, whereby only one reclosing relay 13 is used. The restraining Winding 15 is connected directly across the resistor 7 and, theoperating winding 17 is arranged to be connected between ground and substantially the mid point of the resistor 7 by the relay 19 when it is energized.

lVith such an arrangement, it will be observed that the single relay will operate irrespective of which circuit is the supply circuit since the restraining winding is always energized in accordance with the current through the re sistor 7 and the operating winding is connected so that its energization carriesin accordance with variations in the supply circuit voltage irrcspectively or which circuit is the supply circuit.

The operation of this modification will be obvious from the description of the operation of the system shown in Fig. 1.

While I have shown and described my invention as applied to a particular system and as embodying various devicesdiagrammatically indicated, changes and modifications will be obvious to those skilled in the art, and I therefore aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire'to secure by Letters Patent of the United States, is,-

I. In an automatic reclosing circuit breaker system, two electric circuits, a circuit breaker for connecting said circuits together, an impedance, means for periodically con necting said impedance between saidelectric circuits for a predetermined length of time when said circuit breaker is open, and means controlled by the amount of current flowing through said impedance for effecting the closing. of said circuit breaker.

2. In an automatic reclosing circuit breaker system, two electric circuits, a circuit breaker connecting said. circuits together, means for effecting the opening of said circuit breaker, an impedance, means for connecting said impedance between said electric circuits after said breaker has been open a predetermined length of time, means for disconnecting said impedance from between said electric circuits after it has been con nected therebetween for a certain length of time, and meansresponsive to the amount of current through said impedance for effecting the closing of said circuit breaker.

3. ,In an automatic reclosing circuit breaker system, two electric circuits, a circuit breaker for connecting said circuits together, an impedance, means for periodically connecting said impedance between said electric circuits for a predetermined length of time when said circuit breaker is open, and means controlled by the amount of current flowing through said impedance for eii'ecting the closing of said circuit breaker and for rendering said periodically connecting means inoperative to disconnect said impedance from between said electric circuits until after said circuit breaker is closed.

4. In an automatic reclosing circuit breaker system, a supply circuit, a load circuit, a circuit breaker for connecting said circuits together, an impedance, means for periodically connecting said impedance between said circuits for a predetermined length of time when said circuit breaker is open, and a differential relay for controlling the reclosing of said circuit breaker having a winding connected so as to be energized in accordance with the current through said impedance and an opposing winding connected so that its energization varies in accordance with variations in the supply circuit voltage.

5. In an automatic reclosing circuit break er system, a supply circuit, a load circuit, a circuit breaker for connecting said circuits together, an impedance, means for periodically connecting said impedance between said circuits for a predetermined length of time when said circuit breaker is open, a balance relay for controlling the closing of said circuit breaker having a restraining winding connected in shunt around said impedance when said impedance is connected between said circuits and an operating winding ar ranged to be connected so that its energizat-ion varies in accordance with variations in the supply circuit voltage, and means for completing the circuit of said operating winding after said impedance has been connected between said circuits.

6. In an automatic reclosing circuit breaker system, a supply circuit, a load circuit, a circuit breaker connecting said circuits together, means for effecting the opening of said circuit breaker, an impedance, switching means for connecting said impedance between said circuits, timing means responsive to the opening of said circuit breaker for effecting the periodic closing and opening of said switching means, a difi'erential relay for controlling the closing of said circuit breaker having a restraining winding connected in parallel with said impedance when said switching means is closed and an operating winding arranged to be connected across said supply circuit, and means responsive to the closing of said switching means for effecting the connection of said operating winding across said supply circuit.

7, In an automatic reclosing circuit breaker system, a supply circuit, a load circuit, a circuit breaker connecting said circuits together, means for efiecting the opening of said circuit breaker, a time element relay ar ranged when energized for a predetemined length of time to efiect the closing of said circuit breaker, an impedance, electroresponsive s 'itching means arranged when closed to connect said impedance between said circuits, a closing coil for said switching means, a control relay arranged when energized to effect the energization of said time relay and said closing coil, timing means controlled by said circuit breaker and switching means for effecting the energization of said control relay when said circuit breaker and switching means are both open, and means con trolled by the current through said impedance for completing independently of said timing means an energizing circuit for said control relay.

8. In an automatic rec-losing circuit breakcr system, a supply circuit, a load circuit, a circuit breaker connecting said circuits together, means for effecting the opening of said circuit breaker, a time relay arranged when energized tor a predetermined length of time to eliect the closing of said circuit breaker, an impedance, electroresponsive switching means arranged when closed to connect said impedance between said circuits, a closing coil for said switching means, a. control relay arranged when energized to effect the energization of said time relay and said closing coil, timing means controlled by said circuit breaker and switching means for effecting the energization of said control relay when said circuit breaker and switching means are both open, a diiiierential relay for completing another energizing circuit for said control relay, said relay having one winding connected across said impedance when said switching means is closed and an opposing winding, and means responsive to the closing of said switching means for completing an energizing circuit for said opposing winding.

9. In an automatic reclosing circuit breakor system, two electric circuits, a circuit breaker for connecting said circuits together, an impedance, means for periodically connecting said impedance between said circuits for a predetermined length of time when said circuit breaker is open, a balance relay for controlling the reclosing of said circuit breaker having a winding connected so as to be energized in accordance with the current through. said impedance and an opposing winding responsive to the voltage of one of said circuits, and another balance relay for controlling the reclosing of said circuit breaker having a winding connected so as to be energized in accordance with the current through said. impedance and an opposing winding responsive to the voltage of the other of said circuits.

10. In an automatic reclosing circuit breaker system, two electric circuits, a circuit breaker for connecting said circuits together, an impedance, means for periodically connecting said impedance between said circuits for a predetermined length of time when said circuit breaker is open, two balance relays for controlling the rec-losing of said circuit breaker, each balance relay having an operating winding, and a restraining winding connected so as to be energizedin accordance with the current through saidimpedance, means operative after said impedance has been connected between s ,ld circuits for connecting one of said operating windings across one of said circuits and the other operating Winding across the other of said circuits.

11. In an automatic reclosing circuit breaker system, two electric circuits, a circuit breaker for connecting said. circuits together, a time delay relay arranged when energizedfor a predetermined length of time to effect the closing of said circuit breaker, an impedance, electroresponsive switching means arranged when closed to connect said impedance between said circuits, a closing coil for said switching means, a control relay arranged when energized to eli'ect the energization of said time relay and said closing coil, timing means controlled by said circuit breaker and switching means for effecting the energization oi said control relay when said circuit breaker and switching means are both open, two balance relays, each balance relay being ar ranged to complete an energizing circuit for said control relay and, having a restraining winding connected so as to be energized in accordance with the current through said impedance when said switching means is closed and an operating winding, and means responsive to the closing of said switching means for connecting one of said operating windings across one of said circuits and the other operating winding across the other of said circuits.

In witness whereof, I have hereunto set my hand this 25th day of February, 1926.

ARVID E. ANDERSON.

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