US2336836A - Automatic reclosing circuit breaker equipment - Google Patents

Description

H. BANY Dec. 14, 1943.

AUTOMATIC RECLOSING CIRCUIT BREAKER EQUIPMENT Filed Nov. 30, 1942 Inventor Herman Bang, b fi AZ/4 1 His ttorneg i atented Dec. 14, 1943 AUTOMATEC RECLOSIN G CIRCUIT BREAKER EQUIPMENT Herman Bany, Lansdowne, Pa., assignor to General Electric Company, a corporation of New York Application November 30, 1942, Serial No. 467,287

10 Claims.

My invention relates to automatic reclosing circuit breaker equipments, and one of its objects is to provide an improved arrangement of apparatus for preventing further automatic reclosures of a circuit breaker in case it fails to remain closed for a predetermined time interval after a reclosure.

Another object of my invention is to provide an improved arrangement of apparatus whereby the number of automatic reclosures is unlimited when the opening of the circuit breaker is in response to an abnormal condition of a predetermined character such, for example, as in response to a reverse flow of power through the circuit breaker, and the number of automatic an abnormal condition of a different predeter- 2 mined character.

My invention will be better understood from the following description when taken in connection with the accompanying drawing, the single figure of which diagrammatically illustrates an automatic reclosing circuit breaker system embodying my invention, and the scope of m invention will be pointed out in the appended claims.

Referring to the drawing, 4 represents a circuit breaker connecting a generator 2 to a load circuit 3 which is supplied from another source 4. As shown, the circuit breaker l is of the wellknown latch-closed type and comprises a closing coil 5, a latch 6 for holding the circuit breaker in its closed position, an overcurrent trip coil 1 connected in sreies relation with the source 2 When the circuit breaker l is closed and arranged to release the latch 6 when the current through the trip coil 1 exceeds a predetermined value, and a second trip coil 8 which, when energized, also effects the release of the latch 6. Preferably the circuit breaker l is of the well-known tripfree type. As shown in the drawing, the energization of the trip coil 8 is controlled by a reverse power relay 9 which is responsive to the direction of the flow of power through the circuit breaker l and by an associated control relay l9 which is so controlled by the reverse power relay 9 that the trip coil 8 is energized when power flows from the load circuit 3 to the source 2. Under normal operating conditions, the relay It is energized and maintains the circuit of the trip coil 8 open, but when a reverse power flows through circuit breaker I, the reverse power relay 9 opens its contacts I l and effects the deenergization of the control relay It] which, after being deenergized for a predetermined time, closes its contacts I2 and completes an energizing circuit for the trip coil 8. It will be evident, however, that the relay Hl does not have to have a time delayed drop out in order to obtain proper operation.

For efiecting an automatic reclosure of the circuit breaker I after each opening thereof, I

provide a reclosing relay i3 which is normally arranged to be energized in response to each opening of the circuit breaker and which, when energized, effects the completion of an energizing circuit for the closing coil 5 of the circuit breaker I. As shown the relay l3 has a time delayed pick up but it will be evident however that it can have an instantaneous pick up in case an instantaneous reclosure is desired. The reclosing relay i3 is also arranged to effect the energization of a control relay 14 as soon as the circuit breaker I closes. The control relay i=3, in turn, interrupts the original energizing circuit of the control relay I3 so that it cannot be reenergized to effect another reclosure until after the relay M has returned to its deenergized position. The relay l4, when energized, also completes a locking circuit for itself through the contacts of a time relay I5 which, in turn, is arranged to open its contacts in the holding cincuit of the relay i4, a predetermined time after the relay [4 becomes energized. When the relay l i returns to its deenergized position, an energizing circuit is completed thereby for the control relay 15 to restore it to its normally energlzed position.

In accordance with the embodiment of my invention shown in the drawing, I provide an arrangement of connections so that if, after any reclosure, the circuit breaker I again opens before the control relay I t returns to its deenergized position, an energizing circuit is completed for a lookout relay i6 so that it opens its contacts I1 and interrupts the energizing circuit of the reclosing relay l3 and thereby prevents any further automatic reclosures as long as the lockout relay I6 is held in its energized position by the latch l6.

Since it is desirable not to lock out the circuit breaker l in response to momentary reversals of power through the circuit breaker produced by fluctuating load conditions, I also provide an arrangement whereby the lockout relay I5 is prevented from being operated to its lockout position in response to an immediate reopening of the circuit breaker when the reopening is due to a reversal of power through the circuit breaker. This result is accomplished by havin the reverse power relay 9, when it operates to effect an opening of the circuit breaker i, also effect the opening of the energizing circuit of the lockout relay it so that it cannot be completed by the relay 15 closing its contacts 3'! while the circuit breaker is open.

The operation of the embodiment of my invention shown in the drawing is as follows: When the circuit breaker l is closed and thesourceZ is supplying normal current to the load circuit 3, the various control devices are in thepositions in which they are shown the draWin'g The control relay I is energized by a holding "circuit which includes the contacts 28 of the relay IE1 and the contacts I! of the reverse. power. relay 9, and an energizing circuit is completed for the control relay I5 through the contacts I? or the lockout relay l6 and the contacts 21 of the conm r a la. i

H When thacurrent supplied bythe source 2 to the load circuit it exceeds a predetermined value,

the oyercurrent trip coil 1,re1eases.the.latch 6 and effects the openingoi the circuit breaker. I.

for the closing coil 5 to. efiect .the reclosing or" the circuit breaker l. The closing of the am;- iliary contacts 26 of the circuit breaker .l com- 1 16 rpug the contacts ll of .the lockout relay l6, thecontactszlof the control. relay l5, and the contacts 27, of the. reclosing relay. l3, an energizing circuit for the .control relay 1.4 which, in turn, completes a locking circuit .for.itself throughrits contacts 28, the contacts 24. of the control, relay l5, andthe contacts ll. oftheilockout relay 5., The, opening ofthe, contacts. 2.5 of the relay M. interrupts the..energizing circuit of the control relay.l5.whic h, after bein'g de'energized for a predetermined time, opens itscontacts 24 in the holding circuit of the. control relay. Hi. After being deenergized. .for. a predetermined time, the control relay ll returnsto-its normally deenergized positionand closes .its contacts .21 therebyreestablishing. the. energizing circuit of the control. relay, I so that the control devices are restored to their normal positions,

If when the circuit breaker is reclosed the over current trip coil 1 operates immediately to effect .anotheropeningof the circuit breaker before the relay ['4 is restored. to its deenergized position, the. closing of the auxiliarycontacts 29 of the circuit breaker completes through the contacts 30 of the .cqntrol relay Hi, the contacts 3! of the control relay l5, and the contacts .320]? the control relay 13, an energizing circuit for the lookout relay [5 so that it opensits contacts H in the energizing circuit of the reclosing relay l3 and thereby -prevents any further automatic reclosures of the circuit breaker. It willbe seen, however, that if the circuit breakerfl is not opened until after the control relay M has been restored to "its deenergized position,- tlie above described energizing. circuit of the lookout relay It cannot be completed in response to the next opening of thecircuitbreaker.

When the circuit breaker l is closed and'po-wer flows from the load circuit 3 to the source 2, the reverse powerrelay 9 opens its contacts i l and interrupts the holding circuit of the control relay Hi. The closing of the contacts i2 of the control relay Hi completes through the auxiliary contacts of the circuit breaker i an energizing circuit for the tripcoil 8 so as to effect the opening of the circuit breaker l. The opening of the circuit breaker l efiects an automatic reclosure of the circuit breaker in the same manner as above c: scribed, and the closing of the auxiliary contacts Moi the circuitbreaker I completes through the contacts 35 of the control relay M an energizing circuit for the control relay ill so that it com pletes a holding jcircuit for itself through the contacts H before the circuit breaker i is reclosed.

If a reversal of power occurs immediately after the circuit breaker I is reclosed, the control relay it] is operated in the manner above described to effect another opening of the circuit breaker Furthermore, the opening of the. contacts '32 of the control relay. l8 interrupts. the heretofore described energizing circuit. of thelockout relay It so as to prevent this relay from beingenerized by the closing of the auxiliary, contacts 38 of the circuit breaker I while the control relay I Q is energized and the control relay i5 is 'deenerwi... H,

While l have, in accordance withv the Patent Statutes, shown andjdescribed my invention. as applied to a particular system and as embodyingyarious devices diagrammatically indicated, changesiand modifications will be obviou to those skilled in the art, and I therefore aim in the appended claims to cover all such changes andmodifications as fall within the true spirit andscope of my invention.

What; claim as new and desir to secure by Letters Patent of the United States, is:

1. In an automatic reclosing circuit breaker system, two circuits, a circuit breaker interconnecti f said circuits, means for opening said circuit breaker in response to, predetermined abnormal conditionson one of said circuits, means responsive tothe opening of said circuit breaker for effecting the automatic reclosing thereof, timing meansa control device, means responsive to the closing of said circuit breaker by said second mentioned. means for effecting the operation of said control device-means responsive to the operationrof said control device to its operated position for initiating the timing operation of said timing means, means responsive to said timing means completing its timing operation for effect ing the restoration of said control device to its normal position, and means jointly controlled by said timing means and said control device for preventing a subsequent'operation of said reclosing means if said circuit breaker is open while said control device is in its operated position after said timing means has completed its'timi'ng operation. V

2. In an automatic reclosing "circuit breaker system, two circuits, a circuit breaker interconnecting. said circuits, means "for opening said circuit breaker in response to predeterminedabhorrnal conditions on one of said circuits;:me'ansresponsive to the opening of saidcircui't breaker for effecting the autorriatic 'reclos'ing thereof, timing means, a control device, meansresponsive to the closing of said circuit breaker by said second mentioned means for -efie'c'ting 'tlieop'eration of said control device, means responsive to the operation of said control device to its operated position for initiating the timing operation of said timing means, means responsive to said timing means completing its timing operation for effecting the restoration of said control device to its normal position, a lookout device for rendering said reclosing means inoperative, and means jointly controlled by said timing means and control device for eiiecting the operation of said lockout device if said circuit breaker is open while said control device is in its operated position after said timing means has completed its timing operation.

3. In an automatic reclosing circuit breaker system, two circuits, a circuit breaker interconnecting said circuits, means for opening said cirouit breaker in response to predetermined abnormal conditions on one of said circuits, means responsive to the opening of said circuit breaker for effecting the automatic reclosing thereof, two control devices, means responsive to the closing of said circuit breaker by said second mentioned means for efiecting the operation of one or" saic control devices, means responsive to the operation of said one of said control devices for eiiecting the operation of the other control device, means responsive to the operation of said second control device for effecting the restoration of said one of said control devices to its normal position, and means jointly controlled by said control devices for preventing a subsequent operation of said reclosing means if said circuit breaker is open when both of said control devices are simultaneously in the operated position.

4. In an automatic reclosing circuit breaker system, two circuits, a circuit breaker interconnecting said circuits, means for opening said circuit breaker in response to predetermined abnormal condition on one of said circuits, means responsive to the opening of said circuit breaker for eil'ecting the automatic reclosing thereof, two control devices, means responsive to the closin of said circuit breaker by said second mentioned means for effecting the operation or" one of said control devices, means responsive to the operation of said one of said control devices for effecting the operation of the other control device, means responsive to the operation of said second control device for effecting the restoration of said one of said control devices to its normal position, a lookout device for rendering said reclosing means inoperative, and means jointly controlled by said control devices for effecting the operation of said lockout device only when both or said control devices are simultaneously in their operated positions and the circuit breaker is open,

5. In an automatic reclosing circuit breaker system, two circuits, a circuit breaker interconnesting said circuit, means for opening said circuit breaker in response to predetermined abnormal conditions on one of said circuits, means responsive to the opening of said circuit breaker for effecting the automatic reclosing thereof, means for rendering said automatic reclosing means inoperative to effect another reclosure of said circuit breaker if it is opened within a pre- "etermined time interval after any automatic reclosure, and means responsive to an abnormal condition of a predetermined character on one of said circuits for preventing said last mentioned means from rendering said automatic reclosing means inoperative when said circuit breaker is opened by such a fault within said predetermined time interval.

6. In an automatic reclosing circuit breaker system, two circuits, a circuit breaker interconnecting said circuits, means for opening said circult breaker in response to predetermined atnormal conditions on one of said circuits, means responsive to the opening of said circuit breaker for effecting the automatic reclosing thereoi', means for rendering said automatic reclosing means inoperative to effect another reclosure oi said circuit breaker if it is opened within a predetermined time interval ai'ter any automatic reclosure, and means responsive to the flow or power through said circuit breaker in a predetermined direction for preventing said last mentioned means from rendering said automatic reclosing means inoperative when said circuit breaker is opened by such a flow of power.

7. In an automatic reclosing circuit breaker system, two circuits, a circuit breaker interconnecting said circuits, means for opening said circuit breaker in response to predetermined abnormal conditions on one of said circuits, means responsive to the opening of said circuit breaker for effecting the automatic reclosing thereof, two control relays, a lockout relay, an energizing circuit for one of said control relays including contacts of the other control relay wnicn are closed when said other control relay is deenergized and contacts of said lockout relay which are closed when said lockout relay is in its normal position, means responsive to tne operation or said reclosing means for energizing said other control relay to effect an interruption in said first mentioned energizing circuit, and an energizing circuit for said lockout relay controlled said control relays and said circuit breaker so that said energizing circuit for said lockout relay is completed wnen said one of said control relays is, in its deenergized position and toe other control relay is in its energized position and said circuit breaker is open.

8. In an automatic reclosing circuit breaker system, two circuits, a circuit breaker interconnecting said circuits, means for opening said circuit breaker in response to predetermined abnormal conditions on one or said circuits, means responsive to tne opening or" said circuit breaker for effecting the automatic reclosing tllereoi', two control relays, a lookout relay, an energizing circuit for one oi said control relays including contacts of the other control relay wnicn are closed when said other control relay is deenergized and contacts of said lockout relay which are closed when said lockout relay is in its normal position, means responsive to the operation oi said reclosing means for energizing said other control relay to effect an interruption in said first mentioned energizing circuit, an energizing circuit for said lockout relay controlled by said control relays and said circuit breaker, so that said energizing circuit for said lockout relay is completed when said one of control relays is in its deenergized position and the other control relay is in its energized position and said circuit breaker is open, means responsive to the direction of power flow through said circuit breaker, and means controlled by said power direction responsive means for interrupting the energizing circuit of said lockout relay when the power flow through said circuit breaker is in a predetermined direction.

9. In an automatic reclosing circuit breaker system, two circuits, a circuit breaker interconnecting said circuits, means for opening said circuit breaker in response to two different predetermined abnormal conditions on one of said circuits, means responsive to the opening of said circuit breaker for effecting the automatic reclosing thereof; means for limiting the number of automatic reclosures of the circuit breakers when the breaker is trippedin response to one ,of the predetermined abnormal conditions, and means for permitting an unlimited number of reclosures when the breaker is tripped under the other predetermined abnormal condition.

10. In anautomatic reclosing circuit breaker 1 system, two circuits, a circuit breaker interconnecting said circuits, means for opening said cir-

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