US2282246A - Automatic reclosing circuit breaker system - Google Patents

Description

May 5, 1942.

M. E. REAGAN 7 2,282,246 AUTOMATIC RECLOSING CIRCUIT BREAKER SYSTEM 4 Filed Jan. 18, 1939 2 Sheets-Sheet 2 H 4 WITNESSES: INVENTOR M 57049 5 Reagan.

ATTORN Patented May 5, 1942 AUTOMATIC RECLOSING CIRCUIT BREAKER SYSTEM Maurice E. Reagan, Pittsburgh, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application January 18, 1939, Serial No. 251,484

11 Claims.

My invention relates in general to circuit breaker control systems and, more specifically, to control systems for effecting an automatic reclosure of circuit breakers.

The object of my invention, generally stated, is to provide a reclosing system for circuit breakers which, though simple in construction, is reliable in its operation and is economical to manufacture and install.

The principal object of my invention is to effect a substantially instantaneous reclosure of a circuitbreaker which has been opened in response to predetermined circuit disturbances on the systerm,

A more specific object of my invention is to provide an automatic reclosing system for circuit breakers of th trip-free type, in which a substantially instantaneous reclosure of the circuit breaker is obtained after the trip-free mechanism has been latched tov the breaker closing mechanism.

A further object of my invention is to provide a relay system for controlling the opening and closing operation of circuit breakers of the trip free type in which the operation of the control relays in the system is coordinated in such manner with the movement of the trip free mechanism of the circuit breaker to predetermined positions in its travel as to effect a reclosure of the circuit breaker immediately after the trip free mechanism has been latched to the breaker closing mechanism on an opening stroke of the circuit breaker.

These and other objects will become more apparent by reference to the detailed description 15;.

to follow, taken in conjunction with the drawings, in which:

Figure l is a diagrammatic view of one embodiment of my invention with the circuit breaker shown in a fully open position;

Fig. 2 is a similar view wherein the breaker is shown at the beginning of its opening stroke after being automatically tripped open;

Fig. 3 is a view wherein the breaker is shown at substantially the completion of its opening stroke; and

Fig. 4 is a similar view wherein the breaker is shown in its fully closed position.

It is the established practice in the art to which my invention relates to provide circuit breakers ;1

with control systems for effecting an automatic reclosure thereof after the breaker has opened in response to a disturbance on the electrical system to which the circuit breaker is connected such as, for example, an overload on the system or a short circuit or any other disturbance respecting which it is desirable to open the circuit breaker. Inasmuch'as many of these disturbances are of very short duration, it is highly expedient to reclose the circuit breaker as soon as possible in order thatsynchronous machinery and other electrical apparatus, respecting which it is necessary to keep in synchronism, may not get out of step. I

Various forms of control systems have been devised for effecting such an instantaneous reclosure of the circuit breaker after it has been opened in response to a fault on the system. However, it is believed that the control system of my invention presents a solution to the problem which has long existed with respect to systems for effecting automatic instantaneous reclosures of circuit breakers of the trip-free type. j

In automatic reclosing systems designed for such a type of breaker, it has been the practice, for example, to place a lamp in parallel with the control relay which controls the energization of the breaker closing coil so that when the breaker opens a time delay will occur, sufiicient to ensure that the trip-free mechanism and the breaker closing mechanism have been latched before the winding of the closing coil has been reenergized to a sufiicient degree to cause the breaker to reclose. It will be readily understood that should the breaker closing solenoid be energized before the trip-free and breaker closing mechanism have latched, an undesirable pumping action will take place. It will also be appreciated that the lamps are of themselves objectionable in that they are subject to breakage. In addition, different lamps have different electrical characteristics, and, therefore, do not adequately meet the needs for this type of reclosing system.

By my invention, the use of the lamps to provide the time delay on the opening stroke of the breaker has been eliminated, and the control.

system has thereby been improved, inasmuch as I have obtained an accurate and reliable opera tion of the system by rearranging the standard control system in a novel manner.

With reference to Fig. '1, in which my control system is shown with the breaker in the fully open position, reference characters I0 and II represent two distribution systems which may be connected together through a circuit breaker 8 having movable contacts 9a, 9b and 9c carried by breaker arm member l3 which may be suitably linked to members l4 and [5 as shown. The member I5 is connected to a trip-free lever 20,

which is suitably linked to lever member 2i for movement in accordance with the movement of lever 2I and armature 32 of breaker closing solenoid 33. To assist in opening the circuit breaker rapidly, a spring element I2 cooperative with lever arm I4 may be provided for biasing the circuit breaker toward the" open position. Latch meme members 22 and 36 cooperate with members 26 and 2I and provide means for pivoting such members in the various stages of the operation of the breaker as will be fully described hereinafter. A drum switch 39 actuated in accordance with the movement of the member I5 through link member I6 and having contact members it, il and 42, provides the desired sequence of circuit combinations to control the relays which are utilized in my control system.

In order to provide for controlling. the energization of the winding 33 of the breaker, closing solenoid, a relay X having a winding 50 and an associated armature member, 5| and; contact members 52a and 52b, is utilized, and functions in amannerto be. described hereinafter in more detail; A cut-out relay Y having a winding (50 and'an associated armature member 6i and contacts 62a, "62b and 620 functions to produce a deenergization of the winding 33 of thebreaker closing solenoid when the circuit breaker has moved to the closed position, and also to effect a reenerig'ization of the winding 33 when the circuit breaker moves to an open position;

, -'I'.o provide for opening the circuit breaker autom'atica lly upon the occurrence of a fault on the system, I have shown, for example, a relay Bihaving a winding which is connected to the secondary 24 of a current transformer. Relay B operates its armature member 26 and contact members 21 to' control the energization of a'trip device C having a winding 30 and an associated armature member 3| which functions to trip the latch member 22' and thereby open the circuit breaker in a manner to be described in more detail hereinafter.

In order that my invention may be better understood, a detailed description of its operation will now "be given. With the breaker in full open position, asshown in Fig. 1, members 20 and 2I are bothengageclby latching member '22, and provide a'mechanicai connection between the armature 32 of the breaker closing solenoid and link member I5 of the breaker contact operating mechanism, so that when current is applied to the winding 33 of the breaker closing solenoid, the breaker members I5, I4 and I3, whichare suitably linked for cooperative movement as shown,.wil1 move in accordance with the movement of armature 32 and will close the breaker contacts 9a, 9b and 90.

To initially close the circuit breaker a manual switch 4.3 is moved to a closed position as shown, and a circuit is thus established through winding of control relay X, which extends from conductor 80 of a cur-rentsouroe through conductor 18,.manual switch 43,conductor T9, closed contacts 620 of relay Y, conductor 15, drum switch contacts 4|, which are closed when the circuit breaker is in open position, conductors II2, II! and IHLWinding 50 of relay X, conductor '90, resistor I26 and conductor 11 to the conductor 8I of the'current source.

When the relay winding 5%] is thus energized, its associated armature member 5| actuates the contacts'52a and'52b to the closed position thereby establishing a circuit for energizing the winding'33 of the breaker closing solenoid which extends from conductor 30 of the current source, through conductor I36, winding 33, conductor Itt, closed contacts 52a of relay X and conductor IN to the other conductor 8| of the current source. Contact members 521)- of relay X function to lock in the relay through a holding circuit which extends from conductor 8i of the currentsource through conductor I8, manual switch Q3, conductor IM, closed contact members 52?), conductors It? and H6, relay winding 52, conductor cc, resistor I20 and conductor IT to the other conductor i of the current source.

When winding 33 of vthe breaker closing solenoid is energized, its armature member 32 moves in a downwardly direction and moves the circuit breaker, as hereinbeiore explained, to the closed position shown in Fig. 4.

Referring now to Fig. 4, with the breaker in closed position as shown, it will be apparent that the drum switch contact members 40 have now moved to a closed position, and a circuit'for energizing winding -39 of the cut-off relay Y is now established fromconductor 68 of the current source through conductor I68, drum switch contact members it, conductor I0, resistor 88, relay winding 6%, and conductors IEH, and W5 to conductor 8i. a When the relay winding 59 of relay Yis thus energized, its associated armature member GI actuates contact members 620 to the open position and contact members 62a and 62b to the closed position. When contact members 6211 are closed, it will be apparent that the winding 50 of relay X is shunted through conductor 82, contact members 32a and conductor Hi. This will cause a deenergization of relay winding 5i! and cause its armature member 5I to move downwardly to an open position. When the relay winding 50 is thus deenergized, contact members 52a open and function to disconnect the winding 33 of the breaker closing solenoid from the current source and 85. The winding33 remains disconnected and deenergized so long as the circuit breaker remains in its closed position.

When the contacts 622) are thus closed, a holding circuit for relay Y is established from conductcr to through conductor 13, resistor 14, closed contact memberstzb, conductors 83 and 85, resistor 88, relay winding 60, conductors NH, and 35 to conductor 8!. Relay Y remains energized while the circuit breaker is in a closed position.

Referring now to Fig. 2, when a fault appears on the system, winding 25 of relay B will receive sufiicient current from the secondary winding 24 of the current transformer to cause its armature member 25 to move in an upwardlydirection to close contact members 2'I. When contact members 21 are closed, a circuit is established for energizing winding '38 of the trip device C from conductor 8| through conductor IIl'I, closed contact members 27, relay winding 30, conductors 89, 85 and I9, drum switch contacts 40 and conductor we to conductor 8i).

When the relay winding 38 of trip device C is thus'energized, its armature member 3I is caused to move outwardly and move the latch member 22 against the biasing action of spring 23 to the position shown in Fig. 2 and release the tripfree and closing mechanisms of the circuit breaker.

It will be apparent that when the lever 20 is released from the holding action of latch member 22, the trip-free mechanism embodying the lever 26 and breaker arm member I5, I4 and I3 will be permitted to move in an upward direction to open the breaker contacts independently of movement of the breaker closing mechanism comprising armature 32 and its pivotally connected lever 2|. Such an arrangement results in a much faster opening of the circuit breaker, and is highly desirable to minimize the arcing effects of the breaker contacts.

As may be seen from Fig. 3, when the tripfree lever 23 is carried to an upward position, latch member 36 is caused to cam outwardly against the biasing action of spring 35 to release one end of the member 2|, allowing member 2| to pivot about armature member 32 and carry to an upward position by means of the spring 34. When this has taken place, the trip-free lever 20 and lever 2| will again be in the position as shown in Fig. l, and each will have one end thereof engaged by latch member 22, provided that the fault which caused the circuit breaker to open is no longer present on the system.

When the circuit breaker has approximately completed its opening strok as shown in Fig. 3, drum switch contacts 42 reclose and Winding 60 of relay Y is now shunted out through a circuit which may be traced from conductor I89 through drum switch contact members 42 and conductor l2.

When the relay winding 60 is thus shunted out, a deenergization of this winding will be effected, and its associated armature member '6! will move downwardly to an open position, thereby opening contact members 62a and 62b and closing contact members 620. When the contact members 520 are closed, the circuit for energizing the winding 50 of relay X is reestablished, as hereinbefore described, and results in a reenergization of the winding 33 of the breaker closing solenoid, which efiects a reclosing of the circuit breaker.

It is well known to those skilled in the art that when winding 60 of relay Y is shunted out, as hereinbefore described, there is a certain inherent time constant or time delay between the time that the shunt is placed across the winding 60 and the time it takes for the relay winding 60 to dissipate its energy and allow its associated armature member 6| to move downwardly to the deenergized position of the relay.

Likewise when relay Y has moved to its open position, thus efiecting a reenergization of winding 50 of relay X, there is also an inherent time delay between the instant that current is applied to winding 50 for reenergization, and the time it takes for the magnetic field to build up in this winding and cause its associated armature member 5| to move to a closed position. When relay X moves to its closed position and closes the circuit for reenergizing winding 33 of the breaker closing solenoid there is also a time delay between the instant that this circuit is closed and the time that it takes for a magneic field to build up in winding 33 which is sufficient to initiate a movement of armature 32 of the breaker closing solenoid. I

According to my invention the time that it takes the trip-free mechanism of the breaker to move from the position as shown in Fig. 3 to that shown in Fig. 1 is made approximately equal to the sum of the three aforesaid time delays inherent in the relay windings 60 and 5% and windings 33 of the breaker closing solenoid.

It will be apparent that since the time required for the relays Y and X to function plus the time necessary to energize Winding'33 of the breaker closing solenoid to a degree sufiicient to initiate movement of its armature member 32 is made equalto the time taken by the breaker tripfree mechanism in moving from the position shown in Fig. 3 to the position shown in Fig. 1, the circuit breaker closing mechanism will begin its reclosing movement as soon as the trip-free mechanism has been latched to it. Should it be desired to utilize other forms of breaker closing mechanisms in lieu of the closing solenoid shown,in which no element of time delay is present, it will be obvious that in such event, the time required for only the relays Y and X to function is made equal to the time required by the trip-free mechanism in moving from the position shown in Fig. 3 to the position shown in Fig. 1.

It is evident that other forms of trip-free mechanisms utilized with circuit breakers may be used instead of the particular device which I have shown, it being understood that the primary object of my invention is to coordinate the energization or deenergization, as the case may be, of relay windings 50 and 60- and winding 33 of the breaker closing solenoid with the movement of the circuit breaker trip-free mechanism so that an automatic reclosure of the circuit breaker is effected immediately after the tripfree mechanism has been latched to the breaker closing mechanism.

It will also be evident that other forms of circuit breaker tripping devices which operate in response to predetermined circuit conditions may be Used instead of the particular one which I have'shown, and also that other forms of switch contact mechanisms which function in accordance with the movement of the circuit breaker contact closing mechanism may be substituted for the particular embodiment shown without departing from the spirit and scope of my invention.

I claim as my invention:

l. In an automatic reclosing circuit breaker system, in combination, a circuit breaker having a trip-free operating mechanism, closing means for said breaker, means for opening said breaker, control relay means for initiating operation of said closing means, cut-off relay means effective when operated to ole-energize the control relay means, and a multi-contact switch means including linkage means for effecting operation thereof in accordance with the operation of said breaker mechanism for sequentially controlling the operationof said control and said cut-off relay means, whereby the control relay means is rendered ineffective during the time the breaker is closed and until the trip-free operating mechanism :becomes relatched in the event the breaker opens.

2. In an automatic reclosing circuit breaker system, a circuit breaker having an operating mechanism, means for closing said breaker, means responsive to abnormal circuit conditions for opening said breaker, a control relay effective when energized to initiate operation of said closing means, a cut-off relay energized when and during the period in which said breaker is closed and'effective when energized to shunt out the winding of and therebydeenergize said control relay, a plurality of switch means for respectively controlling the energization of said control and cut-off relays and for shunting out the winding of and thereby deenergizing said cut-off relay, and linkage means connecting all of said switch means for operation in accordance with the movement of said breaker operating mecha-- nism. 4

3..In an automatic reclosing circuit breaker system, the combination of a circuit breaker provided with an operating mechanism including trip-free and breaker closing mechanisms including coupler means for said mechanisms operable when said breaker has opened, means for opening said breaker in response to predetermined circuit conditions, means for actuating the breaker closing mechanism, a control relay for initiating energization of said actuating means, a cut-off relay effective when energized to render said control relay inoperative, and switch means operable in accordance with the movement of said operating mechanism for sequentially .con

trolling the operation of the control and cut-off relays, whereby the cut-off relay is energized when the breaker is closed to render the control relay ineffective and de-energized as the breaker approaches its full .open position to again render the control relay effective.

4. In an automatic reclosing circuit breaker system, a circuit breaker provided with trip-free and breaker closingmechanisms including means for coupling said mechanisms for unitary movement on a breaker closing action, means responsive to predetermined circuit conditions for opening said breaker, a closing solenoid for the breaker closing mechanism, a control relay effective when energized to produce energization of said closing solenoid, a cut-off relay energized during the period in which said breaker is in a closed position and operable when energized to shunt out the winding of said control relay, switch means for controlling the operation of said control and cut-oiT relays, and linkage means connecting said switch means to said tripfree mechanism for actuating last said means in accordance with the movement of said tripfree mechanism, said switch means being operable at a preselected time in advance of the op eration of said coupler means to deenergize the winding of said cut-off relay and to connect said control relay for reenergization.

5. In an automatic reclosing system for a circuit breaker provided with independently movable trip-free and breaker closing mechanisms including means for latching said mechanisms together for unitary movement following an opening stroke of the breaker, means responsive to predetermined circuit conditions for opening said breaker, a closing solenoid for the breaker closing mechanism, a control relay effective when energized to energizesaidclosing solenoid, a cutoff relay continuously energized when said breaker is in a closed position and operable when energized to deenergize said control relay, and means controlled by said trip-free mechanism to deenergize said cut-off relay and reenergize said control relay at a predetermined time in advance of the operation of said latching means whereby when said breaker is in closed position and operable to deenergize said control relay, and means controlled by said trip-free mechanism for controlling the operation of said control and cut-off relays, said cut-off relay being deenergized at a predetermined time in advance of the operation of said coupling means whereby a reclosure of said circuit breaker is initiated immediately after said trip-free and breaker closing mechanisms have been coupled. a

7. In an automatic reclosing system for a circuit breaker provided with independently movable trip-free and breaker closing mechanisms including means for coupling said mechanisms for unitary movement on a closing stroke of said breaker, means responsive to predetermined circuit conditions for opening said breaker, closing means for the breaker closing mechanism, a control relay effective when energized to render said closing means effective, a cut-off relay energized when and during the period in which said break.- er is in closed position and operable when so energized to shunt out the winding of and thereby deenergize said control relay, and a plurality .of switch means including means for effecting operation thereof in accordance with the movement of said trip-free mechanism to predetermined positions in its travel for respectively controlling the operation of said control and cut-off relays.

8. In an automatic reclosing system for a circuit breaker provided with separate trip-free and breaker closing mechanisms including means for coupling said mechanisms together for unitary operation on a closing stroke of said breaker, an overload relay for opening said breaker, electromagnetic means for actuating said breaker closing mechanism, a control relay effective when energized to efiect energization of said electromagnetic means, a cut-off relay energized upon closure of said breaker and effective only when energized to short circuit and deenergize the winding of said control relay, means for short circuiting and deenergizing the winding of said cut-off relay, and a plurality of switches including means for effecting operation thereof in accordance with the movement of said tripfree mechanism to predetermined positions in its travel for respectively controlling the energization of said control relay and said cut-01f relay and for efiecting an operation of said cutoff relay short-circuiting means.

9. In an automatic reclosing circuit breaker system, a circuit breaker having trip-free and breaker closing mechanisms and including means for latching said mechanisms together for a closure movementfollowing an opening stroke of said breaker, means responsive to predetermined circuit conditions for opening said breaker, a closing solenoid for the breaker closing mechanism, a control relay effective when energized to produce energization of said closing solenoid, a cutoff relay operable when in energized position to deenergize said control relay, and switch means including means for sequentially controlling the operation of the control and cut-off relays for effecting operation thereof in accordance with the movements of the breaker, whereby the cut-ofi relay is energized when the breaker is closed and de-energized at a predetermined time in advance of the operation of said coupling means to render the control relay effective to re-energize the closing solenoid, said time being determined by the sum of the time constants of said control and cut-off relays and saidclosing solenoid whereby said circuit breaker is made to begin a reclosure immediately after said trip-free and breaker closing mechanisms are latched.

10. In an automatic reclosing circuit breaker system, in combination, a circuit breaker having separate trip-free and solenoid operated breaker closing mechanisms including means operable when said breaker has opened for coupling said mechanisms for unitary movement upon a closure operation of the breaker, means responsive to predetermined circuit conditions for opening said breaker, a control relay effective when energized to energize said breaker closing solenoid, a cut-01f relay effective when energized to deenergize said control relay, switch means interposed in the relay winding circuits of said control and cut-off relays respectively, switch means for shunting the winding of said cut-off relay, and means for connecting all of said switch means for operation in accordance with the movement of said trip-free mechanism, said cut-ofi relay winding being shunted out by closure of its respective switch means at a time in advance of the operation of said coupling means equal to the sum of the time constants of said control and cut-off relays and said closing solenoid.

11. In an automatic reclosing circuit breaker system, in combination, a circuit breaker having separate trip-free and solenoid operated breaker closing mechanisms including means for coupling said mechanisms together upon an opening stroke of the breaker, means responsive to abnormal circuit conditions for opening said breaker, a control relay efiective when energized to energize said breaker closing solenoid, a cut-ofi relay energized when and during the period that said breaker is closed to shunt out the winding of said control relay, switch means interposed in the winding circuits of said control and cut-ofi relays respectively, switch means for shunting the winding of said cut-off relay, and means for connecting all of said switch means for operation in accordance with the operation of said breaker,

said winding for the cut-ofi relay being shunted out by closure of its respective switch means at a time in advance of the operation of said coupling means, said time being equal to the sum of the time constants of said control and cut-ofi relays and said closing solenoid.

MAURICE E. REAGAN.

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