US2154669A

US2154669A - Automatic reclosing circuit breaker system

Info

Publication number: US2154669A
Application number: US121587A
Authority: US
Inventors: Loache Robert L De
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1937-01-21
Filing date: 1937-01-21
Publication date: 1939-04-18
Anticipated expiration: 1956-04-18
Also published as: DE706749C

Description

April 18, l939. R. DE LOACHE 2,154,669

AUTOMATIC RECLCSING CIRCUIT BREAKER SYSTEM Filed Jan. 21, 1937 Control Source;

' IIIWENTQR I Robert L. d6 0006s..

Patented Apr. 18, 1939 umrsosnrss' PATENT OFFICE aim sworn-no ascmsmo cracurr mama Atlan -Westinghous; aectrio& nnractnringos: p lmlsst burgh. aoerporeiien Application Mai, :1, 1m, sum Ne. ,isissr 1'0 Claims. (Oi. us-su) My invention relates. generally, to circuit breaker systems, and, more particularly, to auto:

matic reclosing circuit breaker systems.

The object or my invention, generally stated. is s to provide an automatic reclosing circuit breaker system which comprises a simple control system using a minimum number oi inexpensive relays and circuits which may be economically manu-p tactured and installed and which shall be simple l0 and eilective in operation.

Another object of my invention is to provide an automatic reclosing circuit breaker system. which may be economically installed to operate circuit breakers already inuse in the held by simple electrical and mechanical connections to such circuit breakers andwithcut requiring any special apparatus to adapt the circuit breaker for use with the system. c

A iurther object of my invention is to provide an automatic reclosing circuit breaker system wbichmaybeconstructedoi'simpleandinexpensive relays and switching devices which aeliknowninthe'artandarereliableinoperaon.

Another object o! my invention a to an automatic reclosing circuit breaker syst m which shall function to instantaneously reclose a circuit breaker aiter it has been opened in-response to .an abnormal or predetermined dition on the line controlled by the circuit to automatically reclose the breaker at predetermined timed intervals in the event thatthe breaker tripsontheiirstoranysubsequentreclosure and to render the system ineirective' to i reclosethebreakeratapredeterminedtimeatter theilrstopeningintheeventthatthebreaker continues to reopen upon being reclosed.

A still further object or my invention is M provide an automatic reclosing circuit breaker l which will reclose instantaneously upon, being opened in response to a predetermined condition on the line controlled by the breaker which will be closed at timed intervals and which will not be reclosed instantaneously in the event that it l 'istays closed after an automatic reclosure until such predetermined time has elapsed .irom the last closure of the breaker.

' A still further object of my invention is to provide an automatic reclosing circuit breaker system 0 which shall function to reclose a circuit breaker a predetermined time aiter each opening of the breaker and to render the reclosing means inoperative to reclose the breaker at a time which shall depend upon the relative lengths of time 5 thatthebreakerremainsinthecloeedandopen In practicing my invention in its preferred position in any seriu of openings of the breaker in which of time between openings of thebreaker are relatively close to the lengths of time between opening and reclosing oi the form, a control relay is provided for energizing the circuit breaker closing solenoid or other closing means in response to the opening operation 'of the breaker.. The energizing circuit for the 10 control relay includes the normally closed contact members of atiming relay which is enersized and operated in response to the closure of the breaker and the control relay in order to deenergise the control relay. 'lhetimingrelayis s I so constructed that it has a delayed reclosing action which delays the subsequent successive reclosures oi thebreaker for a predetermined time interval depending upon the setting of the relay.

' A time controlled relay, whose time delay is govso erned by the total time that the circuit breaker is openand the time that it remains closed, is provided for locking out the circuit breaker to prevent such a number oi circuit breaker operationsas might damage the breaker. 25

Additional objects oi. my invention will be pointed out in the following ducription oi' the same, taken in connection with the accompanying. drawing, whereinl'igurelisadiagrammaticvlewoianautoso matic reclosing circuit breaker system embodying the principal i'eatur'a oi my invention, and

Fig. 2 is a diagrammatic view or a modification oi the invention in which an automatic resetting means for the lock-out device is provided.

Referring tol'lg. La'circuit breaker It is shown as connecting power source ii with a load circuit II. The circuit breaker II is normally biased to the open position by well known means, not shown in the drawing, and is held in the 0 closed position by a latching device il.

Means for trippins the breaker "is provided and is shown as a trip coil it which disengages the latch device II when energized by current from coil it which represents an overload responsive device on the load side of the breaker.

Circuitbreaker ilis closed by the usual closing coil shown as coil II. The energisation oicoil II is controlled by contact It which connect the coil with the control power source represented by lines I and Y through conductors II, as and It.

The control source reierred to may beeither alternating or direct current. When alternating currenthusedtherectiiieru-is provided to supply direct current to energize the closing coil I5. In the event that direct current is used, this rectifier may be eliminated and the coil I5 connected directly to

conductors

23 and 23.

The circuit breaker I3 is provided with auxiliary contact members 3I which are closed when the breaker is in the closed position as shown, and auxiliary contact members 32 which are open when the breaker is closed. The function of these contact members 3I and 32 will be described more in detail hereinafter.

In order to provide for timing the reclosing operations of the breaker a time delay relay I3, having contact members 23 and operating coil 33, is utilized. Element 2i is a diagrammatic showing of the retarding device for this relay which will retard the closing of contact members 23 for a predetermined time after the deenergization of coil 33; the opening of contact members 23, however, is accomplished immediately upon energization of coil 33.

The time delay device 2| is shown as a dash pot in the drawing but may be any device, several of which are well known in the art, which will perform the function 01 delaying the closing of contact members 23. An example of structure which might be used to accomplish the function of contact members 23 and its time delay device 2I is the time delay switch illustrated by the patents to Rhodes 1,353,850, September 28, 1920, and 1,773,697, August 19, 1930.

A thermal current relay having normally closed contact members for controlling the energization of coil IBa of control relay I3 is provided and is shown generally at 23. This relay in the preferred embodiment of the invention comprises a heating element 24, which, when energized, raises the temperature of bimetallic element 25 and when this temperature reaches a predetermined value, bimetallic element 25 flexes to open contact members 23 and to engage behind the latch device, shown generally at 21, to lock contact members 26 open. The value 01' the current flowing through heating coil 24 may be adjusted by an adjustable rheostat 33 which is connected in series with heating element 24.

Means for maintaining the control relay coil I8a energized until the circuit breaker has been reclosed is provided in contact members 31 which are actuated to closed position when coil Ila is energized to form a holding circuit for coil Ila comprising conductor 33, contact members 31,

conductors

39, 43 and 35, contact members 23,, conductor 4i, coil I3a, conductor 42, contact members 26, bimetallic element 25 and conductor 34. This circuit is provided so that positive closure of circuit breaker I3 may be obtained before deenergization of its control relay 3.

The elements of the system are shown in their normal positions with the circuit breaker in normal closed position.

In operation, when an overload or other fault, such as a ground or short circuit on the load circuit I2, causes the circuit breaker to trip open by means of overload coil I4 and trip device I3, a circuit for operating the control relay I3 is established by closure of contact members 32 which extends from supply conductor Y through conductor 43, contact members 32, conductor 35, contact members 23, conductor 4|, coil Ila, conductor 42, contact members 23, bimetallic element 25 and conductor 34 to the other supply conductor X. This energization 01' control relay coil I 3a causes the closure of contact members I3 to energize the closing coil I5 of the breaker through conductor 23, rectifier 44, closing coil I5, conductor 23, contact members I6 and conductor 33, thus causing an immediate reclosure oi the circuit breaker I3.

When the circuit breaker I3 is actuated to its closed position, auxiliary contact members 32 are opened but the control relay I3 is held closed by a holding circuit comprising conductor 33, contact members 31, which were closed when relay I3 was energized by the opening of the breaker,

conductors

33, 43 and 35, contact members 23, .conductor 4|, coil I3a, conductor 42, contact member 26 bimetallic element 25 and conductor 34. This circuit is interrupted, however, at contact members 23 when the circuit breaker I3 reaches its closed position. At this time auxiliary contact members 3i are closed to energize the time-delay relay I3 through conductor 45, contact members 3i, conductor 46, coil 33, conductor 41, conductor 23, contact members I5 and conductor 33.

When contact members 23 are opened, the energizing circuit of control relay I8 is interrupted and this causes the opening of contact members I3 and 31. The opening of contact members" deenergizes relay coil 33 and contact members 23 are closed after a period of time determined by the time delay setting of the device 2|.

In the event that the fault or other cause for overload on circuit I2 still exists when the circuit breaker is reclosed, overload coil I4 will again acutate trip device I3 to cause the breaker to open immediately upon reclosure. when the circuit breaker I3 again reopens, it will not immediately reclose for the reason that the circuit for the control relay I3 is held open at contact members 23 by the time delay device 2I. Aiter the period or time determined by the time delay device 2I has elapsed, contact members 23 will close to energize coil I3 which will cause the closure of contact members I3 and thus energize the closing coil I5 01 the circuit breaker. If after the second reclosure the fault still exists on the line, the circuit breaker will again reopen and will again be reclosed after the predetermined time determined by the setting 01 the time delay device 2I.

In order to limit the successive reciosures oi the circuit breaker to a desired number such as will prevent damage to the breaker, means is provided for locking the control circuit for the breaker in the inoperative position after a predetermined number oi reclosures have occurred, if the cicuit breaker immediately trips after each reclosure.

This lock-out device comprises the thermal current relay 23 and its latching device 21. This relay is energized all the time that the circuit breaker I3 is open through conductor 43,-contact members 32, conductor 35, conductor 43, 1diustable resistance 36, conductor 43, heating e ement 24, contact members 23, bimetallic element 25 and conductor 34. The heating of the element 24 will be substantially continuous throughout the cycle of reclosures and reopenings oi the circuit breaker, since the time that the circuit breaker stays closed under these conditions is very short.

The thermal current relay is set by adjustable resistance 33 so as to open contact members 23 after a time which is slightly greater than the product oi the time delay period of the time delay relay I3 and the number of reclosures to which it is desired to limit the device after the first instantaneous reclosure, and shortly after this number of reclosures has been made, if the circuit breaker again trips immediately, thermal current relay 24 will act to lock the circuit of controlrelay ll open by movement of bimetallic element 2! to open contact members 20 and to latch them open by means oi device 21.

As an example, if it is desired to have the circuit breaker close instantaneously and then recloseafter a period of two minutes if'it trips again immediately and then to lock out, the time delay device 2i of relay is will be set to allow the closure of contact members I! after a period of two minutes and thermal current relay 23 will be adjusted by means of resistance 26 to'open contact members 26 after a period of .three minutes. Then if the circuit breaker trips, it will be reclosed immediately; if it trips again immediately it will be reclosed after two minutes; if it retrips again immediately thermal current relay 23 will-have but one more minute to run before opening its contact members 28 to lock out the device and time delay device 2i will have two minutes to run before again closing contact members 20 to energize control relay it. Thus, the control circuit will be locked out before the circuit breaker can be reclosed for a third time.

Obviously, the periods between reclosure and the number of reclosures may be adjusted as desired by adjusting the time delay of time delay device 2| and the time delay of thermal current relay 23. Howeven'the first reclosure of the breaker will be instantaneous ii. the opening of the breaker occurs at a time after the last closure of the breaker which is greater than the time delay of the time delay device 2|.

In order to set the system in operation again, it is necessary that the bimetallic element 25 be released from the latching device 21 to close contact members 28. This may be done by releasing the latch by hand.

In the modification shown in Fig. 2 of the drawing, there is shown a means for releasing the latch on bimetallic element 25 to close contact members 26 by operation of the control relay and to energize relay it through an auxiliary manually controlled circuit when it is desired to set the system into operation again.

To accomplish this releasing operation, a crank 49 is provided on the latch member of latch device 21 and a shoulder. 50 is provided on the contact member operating arm of control relay It so that the shoulder 50 will operate through the crank 49 to release the latch each time the relay i8 is energized. A push button switch Si is provided to energize control relay i8 from the supply conductors X and Y. When it is desired to reset the device after it has been locked out by the latching of bimetallic element 25 by the latch device 21, push button II is closed to energize control relay I8, thus moving shoulder 50 to cause crank 49 to release the latch 21;- -at the same time contact members l6, shown in Fig. 1,. are closed toenergim the closing coil i5 of the circuit breaker it. It will be noted that the latch device is tripped each time the control relay I8 is operated, but, of course, it will not be effective to affect the reclosing system until after the latch has operated to lock the system out;

It will be apparent from the foregoing description that I have provided an automatic reclosing circuit breaker. system comprised entirely of simple and inexpensive relays and circuitstherefor which will automatically reclose a circuit breaker instantaneouslyafter it trips open and if it continues to trip open, will automatically reclose the circuit breaker after an adjustable predetermined time interval and will limit the reclosures to an adjustable predetermined number, which system is simple, reliable in operation and easily installed either upon circuit breakers already in use in the field or as apart of the breakers as manufactured.

It is understood that the illustration and descriptions of the apparatus used are merely diagrammatic and equivalent structures may be substituted for those shown and described.

I claim as my invention:

1. In an automatic reclosing circuit breaker system, in combination, a circuit breaker, means for automatically opening the breaker in response "to predetermined conditions, means for closing the breaker, a control relay having first and second contact members, said first contact members being in circuit with the breaker closing means, a first and a second'auxiliary contact means, means whereby the first auxiliary contact means is closed when the circuit breaker is open and opened" when the circuit breaker is closed, means whereby the second auxiliary contact means is opened when the circuit breaker is opened and closed when the circuit breaker is closed, an energizing circuit for the control re lay which includes the first auxiliary contact means whereby the control relay functions to cause the circuit breaker to reclose substantially instantaneously after the first opening, a timing relay having normally-closed timed-reclosing contact members in circuit with the control relay coil and the first auxiliary contact means, a circuit for energizing the timing relay coil including the second auxiliary contact means and the first control relay contact members and an additional circuit including said second contact members of the control relay bridging said first auxiliary contact means when the control relay is energized, whereby the circuit breaker will be reclosed at intervals depending upon the time delay of the timing relay in the event that the circuit breaker reopens immediately after the first reclosure.

2. In an automatic reclosing circuit breaker system, in combination, a circuit breaker, means I for automatically opening the breaker in respouse to predetermined conditions, means for closing the breaker, a control relay having first and second contact members, said first contact members being in circuit with the breaker closing means, a first and a second auxiliary contact means, means whereby the first auxiliary contact means is closed when the circuit breaker is open and opened whenthe circuit breaker is closed, means whereby the second auxiliary contact means is opened when the circuit breaker is opened and closed when the circuit breaker is closed, an energizing circuit for the control relay' means when the control relay is energized,

whereby the circuit breaker will be reclosed at intervals depending upon the time delay oi the timing relay in the event that the circuit breaker reopens immediately after the first reclosure, and means in circuit with said first auxiliary contact means for rendering the reclosing system inoperative at a predetermined time after the first opening of the breaker in the event that the breaker will not stay reclosed.

3. In an automatic reclosing circuit breaker system, in combination, a circuit breaker, means for automatically opening the breaker in response to predetermined conditions, means for closing the breaker, a control relay having first and second contact members, said first contact members being connected in circuit with the breaker closing means, a first and a second auxiliary contact means, means whereby the first auxiliary contact means is closed when the circuit breaker is open and opened when the circuit breaker is closed; means whereby the second auxiliary contact means is opened when the circuit breaker is opened and closed when the circuit breaker is closed, an energizing circuit for the control relay which includes the first auxiliary contact means whereby the control relay functions to cause the circuit breaker to reclose substantially instantaneously after the first opening, a timing relay having normally-closed timed-reclosing contact members in circuit with the control relay coil and the first auxiliary contact means, an energizing circuit for the timing relay including the second auxiliary contact means and the first control relay contact members, and an additional circuit including said second control relay contact members bridging the first auxiliary'contact means when the control relay is energized, whereby the circuit breaker will be reclosed at intervals depending upon the time delay of the timing relay in the event that the circuit breaker reopens immediately after the first reclosure, a. thermal current relay controlled by the first auxiliary contact means for rendering the reclosing system inoperative at a predetermined time after the first opening of the breaker inthe event that the breaker will not stay reclosed.

4. In an automatic reclosing circuit breaker system, in combination, a circuit breaker, means for opening the circuit breaker, means including a normally-closed delayed-reclosing relay and a control relay responsive thereto and operable in response to the opening of the breaker for eiIecting a substantially instantaneous reclosure of the circuit breaker, means including said normally-closed delayed-reclosing relay for effecting additional reclosures oi the breaker at intervals determined by the reclosing delay of the delayed-reclosing relay in the event of an immediate reopening of the breaker after the first reclosure, and timing means responsive'to the operation of the breaker for rendering the reclosing system inoperative at a predetermined time after the first opening of the breaker in the event that the breaker will not stay reclosed, said timing means for rendering the reclosing circuit inoperative comprising a relay having normally closed contact means and means for latching said contact means in open position, an auxiliary manually operated control circuit for energizing the control relay, and means oper-' ated by the control relay for tripping the latching means on each operation of the control relay.

5. In an automatic reclosing circuit breaker system, in combination, a circuit breaker, means for automatically opening the breaker, "means for closing the breaker, means responsive to the opening of the breaker for causing the breaker closing means to reclose the breaker substantially instantaneously, timing means for rendering the means which causes the circuit breaker closing means to close the breaker inoperative for a predetermined time after the timing means is actuated and means controlled by the circuit breaker whereby closure 0! the breaker actuates said timing means.

6. In an automatic reclosing circuit breaker system, in combination, a circuit breaker, means for automatically opening the breaker, means for clodng the breaker, means responsive to the opening of the breaker for causing the breaker closing means to reclose the breaker substantially instantaneously, a first timing means for rendering the means which causes the circuit breaker closing means to close the breaker inoperative for a predetermined time after said first timing means is actuated, means controlled by the circuit breaker whereby closure of the breaker actuates said first timing means, a second timing means for rendering the reclosing system inoperative after a predetermined energization of said second timing means and means controlled by the circuit breaker for energizing said second timing means during the open circuit condition of the circuit breaker.

'7. In an automatic reclosing circuit breaker system, circuit breaker closing means, circuit breaker opening means, n'ormally open circuit control means, means for closing said normally open circuit control means when the circuit breaker opens, a timing relay having normallyclosed delayed-reclosing contacts, means for actuating said circuit breaker closing means substantially instantaneously after the opening of the breaker including said normally-closed relay contacts and said normally open circuit control means 8. In an-automatic reclosing circuit breaker system, a circuit breaker closing means, a circuit breaker opening means, a timing relay having normally-closed delayed-reclosing contacts, circuit control means controlled by said circuit breaker, a control relay for said circuit breaker closing means, means for efiecting a substantially instantaneous reclosure oi the circuit breaker in response to the opening of the breaker including said circuit control means, said control relay and the contacts of said timing relay, and means including said timing relay and said control relay for eflecting additional reclosures of the breaker at intervals determined by the interval of reclosing delay of the contacts of the timing relay in the event of an immediate reopening of the breaker after the first reclosure.

9. In an automatic reclosing circuit breaker system, a circuit breaker closing means, a circuit breaker opening means, a timing relay having normally-closed delayed-reclosing contacts, circuit control means controlled by said circuit breaker, a control relay for said circuit breaker closing means, means for eflecting a substantially instantaneous reclosure oi the circuit breaker in load circuit, a circuit breaker between the two ,7

response to the opening of the breaker including said circuit control means, said control relay and the contacts of said timing relay, means including said timing relay for effecting additional reclosures of the breaker at intervals determined by the intervals of reclosing delay of the contacts of the timing relay in the event of an immediate reopening of the breaker after the first reclosure, and additional timing means responsive to said circuit control ,means for rendering the reclosing system inoperative at a predetermined time after the first opening of the circuit breaker in-the event that the circuit breaker "will not stay reclosed.

15 10. In combination, a power supply circuit, a

circuits, means for opening the circuit breaker in response to predetermined abnormal conditions, control relay means responsive to the opening of the breakerfor immediately reclosing the breaker, timing relay means responsive to said control relay means and the reclosure oi the breaker for delaying subsequent reclosures of the breaker in the event that the breaker continues to reopen, and additional timing means responsive to the open condition oi the breaker for preventing reclosure of the breaker after a predeter-