US2031447A - Automatic reclosing circuit breaker system - Google Patents

Description

Feb. 18, 1936. A. E. ANDElSON 2,031,447

AUTOMATIC RECLO'SING CIRCUIT BREAKER SYSTEM Filed Oct. 9, 1934 m T- T A UTOMA r/c RECLOS/NG MEA N5 Inventcw: Arvid E.Ander son,

by ww a (am/4 v is Attorn ey.

4 Patented Feb. 18, 1936 UNITED STATES PATENT OFFICE AUTOMATIC RECLOSING CIRCUIT General Electric New York Company, a corporation of Application October 9, 1934, Serial No. 747,511

' 6 Claims.

My invention relates to automatic reclosing circuit breaker systems and particularly to such systems in which a circuit breaker interconnecting two electric circuits is reclosed substantially instantaneously a predetermined number of times after the initial opening thereof has been effected in response to a fault on one of the circuits, and one object of my invention is to provide an improved automatic reclosing circuit breaker system of this particular type.

In such systems the substantially instantaneous reclosure of the circuit breaker is eifected in some cases by initiating the closing operation before the circuit breaker has completely opened.

In my copending application, Serial No. 741,085, filed August 23, 1934, which is assigned to the same assignee as this application, I have disclosed and claimed an arrangement for accomplishing this result. When such an arrangement is employed to control a circuit breaker of the well-known trip-free type it may be impossible in some cases to effect the substantially instantaneous reclosure of the circuit breaker within the desired time interval, as with such a circuit breaker it is necessary to provide in the closing circuit of the circuit breaker suitable contacts which are controlled by the trip free mechanism so as to insure that after the opening of the circuit breaker, the trip free mechanism has been reset before the closing means is operated. This resetting operation takes an appreciable time and may be longer than the time it is desired to maintain the circuit breaker open.

In accordance with my invention I provide the circuit breaker with twontripping means, one of which will allow the circuit breaker to open only when the closing coil is deenerglzed and the other oi which can effect the opening of the circuit breaker independently of the energized condition of the closing coil. Normally the fault responsive means which effects the opening of the circuit breaker, is arranged to effect the operation of the first mentioned tripping means. After the desired number of substantially instanta- 43 neous reclosures has been effected, the second tripping means is placed under the control of the fault responsive means.

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 its scope will be pointed out in the appended claims. Referring to the drawing,.l represents a supply circuit which is arranged to be connected to a load circuit 2 by a circuit breaker 3. As shown, the circuit breaker 3 comprises a closing coil 4, a trip-free trip coil 5 and suitable operating mechanism whereby when the trip coil 5 is 5 deenergized and the closing coil 4 is energized the circuit breaker is closed, but the energizatlon oi the trip coil 5 at any time effects the opening of the circuit breaker independently of whether or not the closing coil 4 is energized. 10 The circuit breaker 3 also has an additional non trip-free trip coil 6 which when energized is arranged to eifect the opening of the circuit breaker if the closing coil 4 is deenergized. However, if the closing coil 4 and trip coil 6 are simulta- 15 neously energized and the trip coil 5 is deenergized, the closing coil 4 maintains the circuit breaker 3 in its closed position as long as the closing coil remains energized.

For effecting the opening of the circuit breaker 20 3 when it is closed and a fault occurs on the load circuit 2, I provide suitable fault responsive means which is shown as an overcurrent relay 1 connected" so as to be energized in accordance with the current flowing through the circuit 25 breaker 3. When the current supplied to the load circuit 2 exceeds a predetermined value, the overcurrent relay 1 is normally arranged to effect the energization of the trip coil 6 if the circuit breaker 3 is closed. Also, the over-current relay 30 1 initiates the closing operation of the circuit breaker 3 before it has completed its opening. operation. This result is obtained by having the over-current relay 1 complete an energizing circuit for a control relay 3 which in turn completes 35 an energizing circuit for the closing coil 4 of the circuit breaker 3.

In order to limit the number of instantaneous reclosures of the circuit breaker 3 to a predetermined number of reclosures which in the ar- 0 rangement shown is one, a lookout relay 9 is provided which is arranged so that after the initial reclosure it maintains the instantaneous reclosing circuit for the relay 8 which is completed by the over-current relay 1, open for a predeter- 45 mined time interval if the circuit breaker 3 remains closed and permanently open if the circuit breaker is open at the expiration of this predetermined time interval. As shown theoperating coil I0 of this lockout relay 9 is connected in 50 series with the closing coil 4 of the circuit breaker 3. The operating coil l0, when energized. opens the circuit of the relay B, which is completed by the overcurrent relay 1, so that a subsequent operation of the overcurrent relay does not eifect the immediate energization of therelay 8. The relay 9 is arranged in any suitable manner so that it is held in its energized position after the operating winding therefor is deenergized. In the particular arrangement shown, this result is obtained by means of a latch II which holds the relay in its energized position and which is arranged to be released by a release coil l2 when it is energized.

In accordance with my invention the lookout relay 9 also is arranged to place the trip-free trip coil 5 under the control of the cvercurrent relay 1 after the desired number of instantaneous reclosures have been effected. This result is accomplished by having the lookout relay 9, when in its energized position, close contacts in the circuit of the trip coil 5 so that any subsequent operation of the overcurrent relay 1 efiects the energization of the trip 00115.

I also provide additional automatic reclosing means of any suitable type, examples of which are well known in the art, for effecting the reclosing of the circuit breaker 3 a predetermined number of times with relatively long time inter- Vals between successive reclosures in case the circuit breaker does not remain closed after the initial reclosure thereof. Since such automatic reclosing means are well-known in the art and the detail circuits thereof form no part of my present invention, I have deemed it advisable, in order to simplify the disclosure, to represent such automatic reclosing by a rectangle I 3. Anderson Patent 1,784,651, granted December 9, 1930, and assigned to the assignee of this application, discloses the details of an automatic reclosing circuit breaker arrangement which may be used in connection with my invention to effect a prede termined number of successive energizations of the control relay 8 with relatively long predetermined time intervals between successive energizations if thecircuit breaker 3 does not remain closed after each reclosure thereof and for effecting the energization of the release magnet l2 if the circuit breaker 3 is closed after the automatic reclosing means l3 has been in operation for a predetermined time.

The operation of the arrangement shown in the drawing is as follows: Under normal load conditions the circuit breaker 3 remains closed and the control devices are in the positions shown. When an overload occurs which is suiiicient to cause the overcurrent relay I to close its corrtacts, a circuit is completed through the contacts 15 of this relay and the auxiliary contacts IE on the closed circuit breaker 3 for the trip coil 6 so as to effect the opening of the circuit breaker.

At the same time an energizing circuit is completed for the relay 8 through the contacts I1 of the overcurrent relay 1 and the contacts I8 of the lookout relay 9. By closing its contacts 2| relay 8 completes a series energizing circuit for the closing 'coil 4 of the circuit breaker 3 and the operating winding N3 of the lockout relay 9. The energization of the closing coil 4 closes the circuit breaker 3 so as to reconnect the load circuit 2 to the supply circuit I.

The energizationof the operating winding I of the lockout relay 9 causes this relay to open its contacts l8 and close its contacts 22. The opening of the contacts l8 prevents a subsequent energization of the overcurrent relay 1 from effecting a substantially instantaneous reclosure of the circuit breaker 3. The closing of the contacts 22 prepares a circuit for the trip coil 5 so that a subsequent operation of the overcurrent relay I completes an energizing circuit for the trip coil 5.

The closing of the auxiliary contacts 23 on the circuit breaker 3 in response to the initial open.- ing thereof completes a starting circuit 24 for the automatic reclosing means l3. If the fault is still connected to the load circuit 2 at the time the circuit breaker 3 is reclosed, the overcurrent relay 1 again closes its contacts l5 and I1. through the contacts 22 of the lookout relay 9 and the auxiliary contacts IS on the circuit breaker 3 an energizing circuit for the trip-free trip coil 5 so that thecircuit breaker 3 may open while the closing coil 4 is still energized. The closing of the contacts I l at this time does not close the instantaneous reclosing circuit for the control relay 8 because this circuit isnow open at the contacts l8 of the lookout relay 9.

After the second opening of the circuit breaker 3 a relatively long time interval elapses before the automatic reclosing means l3 completes a closing circuit 25 for the control relay 8. When this closing circuit 25 is completed, relay 8 by closing its contacts 2| completes in the manner above described an energizing circuit forthe closing coil 4 to effect another closing of the circuit breaker 3. If the fault is still connected to the load circuit so that the trip coil 5 is again energized to effect the immediate opening of the circuit breaker 3, the automatic reclosing means is arranged in a manner well known in the art to efiect a predetermined number of energizations of the control relay 8 with predetermined time intervals between successive energizations. If the circuit breaker fails to remain closed after said predetermined number of reclosures, the reclosing means is rendered inoperative, in a manner well known in the art, to effect further energization thereof. If, however, the circuit breaker 3 is closed'after the automatic reclosing means I3 has been in operation for a predetermined time, it effects in a well known manner the energization of the release magnet I 2, which releases the latch H and restores the lockout relay 9 to its normal position so that the instantaneous reclosing means is again rendered operative to control the reclosure of the circuit breaker 3. The restoration of the lockout relay 9 to its normal position also removes the trip-free trip coil from the control of theovercuurent relay 1 so that the next opening of the circuit breaker 3 is effected by the trip coil 6.

While I have, in accordance with the patent statutes, shown and described 'my invention as applied to a particular system and as embodying various devices diagrammatically 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:

The closing of the contacts l1 completes means for effecting the energization of said clossubstantially instantaneous reclosures of said circuit breaker after the initial opening thereof and time delayed reclosures thereafter if the circuit breaker fails to remain closed, and means for causing said fault responsive means to eifect the operation of said first mentioned tripping means after said predetermined number of substantially instantaneous reclosures has been effected.

2. In combination, two electric circuits, a circuit breaker interconnecting said circuits, electromagnetic closing means for said circuit breaker, tripping means for effecting the opening of said circuit breaker independently of the energized condition of said closing means, additional tripping means for eflecting the opening of said circuit breaker only when said closing means is deenergized, fault responsive means connected to said circuits and normally arranged to effect the operation of said additional tripping means, means for effecting the energization of said closing means to produce a single substantially instantaneous reclosure of said circuit breaker after the initial opening thereof and time delayed reclosures thereafter if the circuit breaker fails to remain closed in response to its initial reclosure, and means for causing said fault responsive means to effect the operation of said first mentioned tripping means after said substantially instantaneous reclosure has been effected. I

3. In combination, two electric circuits, a circuit breaker interconnecting said circuits, electro-magnet closing means for said circuit breaker, tripping means for effecting the opening of said circuit breaker independently of the energized condition of said closing means, additional tripping means for effecting the opening of said circuit breaker only when said closing means is deenergized, fault responsive means connected to said circuits and normally arranged to effect the operation of said additional tripping means, means for effecting the energization of said closing means to produce a single substantially instantaneous reclosure of said circuit breaker after the initial opening thereof and to produce thereafter a predetermined number of time delayed reclosures within a predetermined time interval after the initial reclosure, and means for render;- ing said fault responsive means operative to effeet the operation of said first mentioned tripping means after said substantially instantaneous reclosure has been effected.

4. In combination, two electric circuits, a circuit breaker interconnecting said circuits, electromagnetic closing means for said circuit breaker, tripping means for eiiecting the opening of said circuit breaker independently of the energized condition of said closing means, additional tripping means for effecting the opening of said circuit breaker only when said closing means is deenergized, fault responsive means connected to.

said circuits and normally arrangedto eflect the operation of said additional tripping means,

ing means to produce a single substantially instantaneous reclosure 01' said circuit breaker after the initial opening thereof and to produce thereafter a predetermined number of time delayed reclosures within a predetermined time interval after the initial reclosure, and means responsive to the initial reclosure of said circuit breaker for rendering said fault responsive means operative for a predetermined time to eilect the operation of said first mentioned tripping means.

5. In combination, two electric circuits, a circuit breaker interconnecting said circuits, closing means for said circuit breaker, tripping means for effecting the opening of said circuit breaker independently of the condition of said closing means, additional tripping means for eflecting the opening of said circuit'breaker only under certain conditions of said closing means, fault responsive means normally arranged to efleet the operation of said additional tripping means, means for effecting a substantially instantaneous reclosure of said circuit breaker including means controlled by said fault responsive means for initiating the operation of said closing means simultaneously with the initiation of the operation of said additional tripping means, means for effecting additional reclosures of said circuit breaker with a relatively long time interval between each reclosure, and means responsive to the initial reclosure for rendering said instantaneous reclosing means inoperative to effect further reclosures and for rendering said fault responsive means operative to effect the operationof said first mentioned tripping means.

6. In combination, two electric circuits, a circuit breaker interconnecting said circuits, electro-magnetic closing means for said circuit breaker, tripping means for effecting the opening of said circuit breaker independently of the energized condition of said closing means, additional tripping means for effecting the opening of said circuit breaker only when said closing means is deenergized, fault responsive means connected to said circuits and normally arranged to effect the operation of said additional tripping means, means for effecting a substantially instantaneous reclosure of said circuit breaker including means controlled by said fault responsive means for initiating the energization of said closing means simultaneously with the initiation of the operation of said additional tripping means, means for efiecting additional reclosures of said circuit breakerwith relativelylong time intervals between each reclosure, and means responw sive to the initial reclosure for rendering said instantaneous reclosing means inoperative to ef- :l'ect further reclosures and for rendering said fault responsive means operative to effect the operation of said first mentioned tripping means.

ARVID E. ANDERSON.

Images