US2319645A

US2319645A - Circuit breaker operating system

Info

Publication number: US2319645A
Application number: US367788A
Authority: US
Inventors: Thumim Carl
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1940-11-29
Filing date: 1940-11-29
Publication date: 1943-05-18
Anticipated expiration: 1960-05-18

Description

May 18, 1943 CLOSE x C C. THUMIM CIRCUIT BREAKER OPERATING SYSTEM Filed Nov. 29, 1940 2 Sheets-Sheet l Figi Inventor: Carl Th umim,

H ls Attorw ey.

CIRCIT BREAKER OPERA'I-ING SYSTEM Filed Nov. 29; 1940 l.2 sheets-sheet 2 AUTOMATIC REcLoslNG CLOSE Swnrcrl Inventor: Carl Th umm,

His Attorney.

Patented May 18, 1943 CIRCUIT BREAKER OPERATING SYSTEM Carl Thumim, Yeadon, Pa., assgnor to General Electric Company, a corporation of New York Application November 29, 1940, Serial No. 367,788

17 Claims.

My invention relates to circuit breaker operating systems, more particularly to pneumatic operating systems for effecting high speed automatic reclosure of a circuit breaker, and has for its principal object the provision of an improved circuit breaker operating and reclosing system of the aforesaid type that is rapid, positive and efficient, particularly with respect to the reclosing operation, that has low input power rating, and that is applicable to large circuit breakers requiring a considerable closing force.

A further object of my invention is the provision of an improved pneumatic automatic circuit breaker reclosing system that is effective to apply the reclosing force in a positive manner and without delay at a predetermined intermediate lpoint in the breaker opening stroke, and that is automatically preset for high speed reclosing.

Means have been provided for quickly reclos- 'f ing electric circuit breakers in electric distribution systems Where continuity of service is a very important factor, one or more times after automatic opening in response to a fault. This is desirable in View of the fact that a very large percentage of faults, such as short circuits due to lightning, for example, can be cleared by a single breaker operation. In synchronized circuits, however, the circuit reclosures must be made at very high speed if the synchronous load is to be held on the line.

From the standpoint of service continuity, the ideal condition is that the breaker be reclosed instantly after the breaker has cleared the fault, preferably after a very short opening stroke. Accordingly, where standard opening and closing mechanisms are employed, reclcsure does not actually start until the full opening stroke has been completed, i. e., an appreciable time after the fault current has been interrupted.

rI'he function of a circuit breaker is not only to open a circuit and clear faults, but also to maintain the circuit clear in the open circuit position under adverse voltage conditions. That is, the length of stroke of the circuit breaker must be suiiicient not only to interrupt the heaviest currents for which the breaker is rated, but also to prevent restriking of the arc in case the line voltage is several times that of normal. As contrasted with this isolating function of the breaker. it should be borne in mind that a well designed breaker can actually clear a fault within a few inches of opening stroke.

In accordance with the present invention, a fiuid motor, such las a piston and cylinder arranged for example for pneumatic operation, is connected to a source of gas pressure, such as a storage tank for closing a circuit breaker and for rapidly reclosing it after a tripping operation with minimum expenditure of gas energy. To this end, means are provided for initially presetting the uid motor with respect to the breaker operating mechanism so that no time is lost in initiating the reclosing operation.

My invention will be more fully set forth in the following description referring to the accompanying drawings, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawings, Figure 1 is a partly diagrammatic layout of a high speed automatic circuit breaker operating and reclosing system in the closed circuit position embodying the present invention, and Figure 2 is a similar View showing the application of the invention to another form of operating mechanism.

rIhe pneumatic operating mechanism illustrated by way of example in Fig. 1 comprises a fluid motor l of the piston and cylinder type, a source of compressed gas 2 for operating the motor and a circuit breaker operating member 3 that is operatively connected by a iiexible linkage 4 to the piston 5 of the uid motor. The circuit breaker (not shown) can in the present instance conveniently be of the gas blast type by reason of the source of compressed gas 2, although it will be apparent that any suitable type can be used.

In the position shown, the circuit breaker operating member or rod 3 is held by means hereinafter described in the closed circuit position, a compression spring 6 biasing the breaker and mechanism toward open circuit position. The operating means interconnecting the breaker rod 3 and the piston 5 may be of the chain linkage type as described and claimed in Thumim Patent 2,112,054, granted March 22, 1938, for Operating mechanism.

The breaker rod 3, which is suitably guided for longitudinal reciprocal movement at 1, is directly connected through the flexible chain linkage i to the piston rod 5. A spring 5" is also connected to the piston rod to bias it toward its upper or reset position. The piston rod 5 is held in the depressed or closed circuit position :shown against the bias of springs 5" and 6 by a prop E that is pivotally mounted at and is biased in a counter-clockwise direction by a spring 8" so as to ride over and engage a pin 9 secured to the piston rod 5'.

The chain linkage 4 is particularly adapted for applications requiring movement of the circuit breaker operating rod at right angles to the direction of the operating force and is held in operative position by a crank ID that is pivotally mounted at II and is provided with rollers I2 and I3 at the extremities of the crank arms. The roller l2 serves as a rolling guide for the chain linkage 4, and the roller I3 cooperates with a pivoted latch I4 that is in turn associated with a tripping solenoid I5. The latch I4 is spring biased at I6 in counter-clockwise direction so that it can reset beneath the roller I3 and the crank I is also biased counter-clockwise by a spring I'I for the purpose of stretching the chain 4 and returning the crank to a reset position with respect to the latch I4 As shown, the crank I is held against rotation by the latch I4 so that the linkage 4 is under tension for holding the breaker rod 3 in closed circuit position.

A more detailed description of the chain linkagemechanism is believed to be unnecessary other than to point out that upon clockwise movement of the latch 'I4 in response to actuation of the tripping solenoid I5, the breaker spring 6 causes rotation of the crank I0 clockwise, taking up slack in the chain 4 and thereby permitting opening movement of the breaker rod. Upon initial clockwise rotation of the crank I0, the prop 8 is also pushed away from the pin roller 9 by reason of a camming action at I0' between the crank Ill and an extension I8 of the prop 8. The piston rod can now move to its upper position, taking with it the piston 5, for producing more slack in the chain 4 so as to allow complete opening of the breaker and to permit resetting of the crank I0 under influence of its spring I1. The breaker is now open and the mechanism reset and in readiness for a closing operation.

It will be* noted that there is a lost-motionV connection between the piston 5 and its operating rod 5'. This is for the purpose of presetting the piston independently of the piston rod and breaker mechanism after the closing operation so that high speed reclosure can take place unhampered by preliminary piston movement durs intermediate or partial stroke position as shown.

This position corresponds approximately to the beginning of the reclosing stroke.

To initiate the normal closing operation of this type mechanism, gas under pressure is admitted to the piston cylinder I9 by a control valve 2li for moving the piston 5 downward,

^ theV piston now being in operative engagement with the piston rod collar 5a at the upper part of the cylinder. The crank I0, which is now reset and inthe position shown, holds the chain linkage taut so that the breaker rod 3 is moved by the 'piston against the bias of opening spring 6 to the closed circuit position shown. When the piston reaches its lower limit of travel, the

prop 8 snaps over the pin roller 9 and holds the breaker in closed circuit position independently of the uid motor I.

The normal tripping operation is as above described, that is, energization of the tripping solenoid I5 in response to a fault condition in the circuit, for example, causes release of the latch I4 and collapse of the chain linkage 4 so as to permit opening movement of the breaker.

It will be noted that the operating mechanism above described is trip-free during the closing operation of the breaker. That is, tripping of the latch I4 prior to complete closing of the breaker is eiective to cause immediate opening movement of the breaker notwithstanding the fact that the piston 5 is in driving relation to the piston rod 5', and hence the mechanism.

The operating mechanism so far described performs the normal circuit closing and opening operations wherein the breaker operating member is moved throughout its full stroke for each operation. That is, when the breaker opens fully, the mechanism carries the piston 5 upward to the beginning of the stroke, and when the breaker is completely closed the piston moves to the end of the stroke against the bias of resetting springs 5d. However, immediately after closing of the breaker and shutting off of the closing force, the presetting means 5c-5d cause return of the piston, independently of the mechanism and circuit breaker, to the intermediate or preset position shown, f

In the case of high speed reclosing, it is essential that the breaker reclosing movement be initiated after but a fraction of the normal opening stroke as previously pointed out. To this end, the fluid motor I is controlled by the valve 20 so that a fresh charge of compressed gas is admitted to the cylinder I9 after predetermined opening of the breaker so that the piston 5 is immediately driven back through a partial stroke to its fully closed position. Since the cylinder working space is small as compared with the case of prior types of piston mechanisms, a comparatively small charge of compressed gas under source pressure quickly raises the cylinder pressure to accomplish at vhigh speed the desired reclosing stroke.

The control means for accomplishing high speed reclosing comprise an auxiliary switch 2I arranged to control energization of the valve operating solenoid 22, and means hereinafter described for controlling tripping of the chain linkage mechanism'at the latch I 4. The auxiliary or reclosing switch 2i is arranged to be engaged by a cam or the like 3 secured to the breaker rod 3 for closing the switch 2I when the breaker rod has moved a predetermined distance toward open circuit position. This distance corresponds to the length of stroke for clearing the fault. The switch 2! is connected so as to be in series with a manual reclosing control switch 23 that is mechanically connected to a tripping switch 24.

. When the reclosing cycle is to be used, the switch 23 is put in the position shown and upon opening movement of the breaker the energizing circuit of the valve solenoid 22 is completed from the source of control voltage indicated at e through the reclosing control switch 23, automatic reclosing switch 2l, source-pressure control switch 25, and a limit or cuto switch 26 that is spring biased towards closed position. The switch 25 is for the purpose of rendering the system inoperative in case of failure ofthe gas source pressure at 2, and the switch 26 automatically deenergizes the valve solenoid-when it is opened 26 also drops down to close the switch 26. When this takes place, the automatic reclosing switch at 2|1is closed, as in Fig. l, for energizing the closing circuit of the Valve solenoid 22. Similar auxiliary switches and control means having corresponding reference numbers are used and, since the functions are generally similar, further detailed description of the mechanism and system is unnecessary and the operation will be clear Y from the following brief description: When the trip coil 36 is energized by the fault relay FR,

the mechanism is tripped open. After predetermined opening movement, the valve solenoid 22 is energized through the auxiliary switches 2|, 26 and 25, and compressed gas is immediately admitted to the cylinder i9. Since the opening movement so far has simply taken up the lostmotion at f, the piston is now in instant readiness to reclose the breaker by rotating the link 4|' counterclockwise. This reclosing operation is possible since 46 is still latched. Near the end of the piston closing stroke the auxiliary limit switch 26 is opened to deenergize the valve solenoid 22.

If now the fault persists even after reclosing, the trip-free coil I5, which is now in the tripping circuit by means of the pressure operated transfer relay TR, is energized to trip the latch itv thereby causing immediate reopening of the breaker to the full open position. In this position the piston 5 is at the lower part of the cylinder, the pin 5e now being in abutting contact Awith the piston rod so that upon resetting of the latch 46, the mechanism is in readiness for a new closing operation. With the pin 5e in its lower position the limit switch 26 is again closed, thereby placing the control circuit in readiness for the next closing operation when the manual switch at C is closed.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

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

1. An automatic reclosing circuit breaker system comprising a iiuid motor operable through a working stroke to close the circuit breaker, a source of iiuid pressure for operating said motor, means for presetting said motor after a working stroke independently of said circuit breaker at an intermediate point in said stroke, a control valve for admitting said fluid to said motor, tripping means for said circuit breaker, and means operative in response to predetermined opening movement of said circuit breaker upon actuation ci said tripping means for opening said valve and causing reversal of movement of said motor from said intermediate point to reclose said circuit breaker through a partial working stroke prior to completion of the opening stroke thereof. i

2. An automatic reclosing circuit breaker system comprising a fluid motor operable through a working stroke to move the circuit breaker to closed circuit position, spring means arranged to be stressed by said fluid motor for biasing said circuit breaker toward open circuit position,

v means for presetting said motor after said working stroke at a point corresponding to a partial down in response to tripping, the slotted link 26a. vinterconnecting the linkage and the limit switch working stroke, said presetting loperation being eiiected independently of said circuit breaker, a source of fluid pressure for operating said motor, a control valve between said source and motor, tripping means for releasing stored energy in said spring means for causing opening movement of said circuit breaker, and means operable by and in accordance with predetermined opening movement of said circuitbreaker for causing opening of said valve and actuation of said iiuid motor through the remainder of said stroke to reclose said circuit breaker prior to completion of the opening stroke thereof.

3. An automatic reclosing circuit breaker system comprising an operating piston, means including a lost-motion connection interconnecting the circuit breaker and said piston, tripping means for said circuit breaker, a spring for biasing said circuit breaker toward open circuit position, a source of iiuid pressure for operating said piston so as to cause closing movement of said circuit breaker against the bias of said spring, means for presetting said pistonv independently of said circuit breaker at an intere mediate point in its closing stroke through `said lost-motion connection, a control valve between tion connection operatively relating said piston to said circuit breaker, said piston arranged to preset to an intermediate position through said lost-motion connection independently of said circuit breaker after the closing stroke, a spring arranged to bias said circuit breaker toward open circuit position independently of said preset piston, a source of fluid pressure for driving said piston through a working stroke to cause closing movement of said circuit breaker through said trip-free connection, a control valve between said source and piston, a latch for releasing said spring for initiating opening movement of said circuit breaker, reclosing means operable in response to predetermined opening movement of said circuit breaker for opening said valve whereby said piston is instantly started from its preset position and the circuit breaker is reclosed prior to completion of the opening stroke thereof, and means for releasing said trip-free connection for causing opening of said circuit breaker in the event that said reclosing operation is concurrent with a circuit fault.

5. An automatic reclosing circuit breaker system comprising a source of gas pressure, a uid motor having a cylinder and piston, a control valve between said source and cylinder, means including a lost-motion connection operatively connecting said piston and the circuit breaker arranged so that said piston is eiective to close said circuit breaker through a positive working stroke and said circuit breaker is free to open initially a predetermined distance independently of said piston, spring means arranged to bias said circuit breaker toward open circuit position, said tripping means for causing opening movementof said circuit breaker, and means for opening said valve upon opening of said breaker said predetermined distance and taking up of said ylost-'motion connection for admitting gas under source pressure to the cylinder space at the working side of vsaid piston for reclosing sa circuit breaker prior to completion of the opening stroke thereof.

6. An automatic reclosing circuit breaker system comprising a source of gas pressure, a iiuid motor having a cylinder and. piston, means including a lost-motion connection operatively connecting said piston to the circuit breaker, a valve for controlling admission of gas from said source to said cylinder to effect a working stroke of said piston for closing said circuit breaker, said piston being independently movable through said lostmotion connection to preset at an intermediate point in its stroke after said breaker closing, fault responsive means for causing opening of said circuit breaker to take up the lost-motion with said piston, and means operable in response to predetermined circuit opening movement of said breaker to cause opening of said valve for admitting gas under source pressure directly to the cylinder working space whereby said piston is moved from its preset position through the remainder or" its working stroke and said circuit breaker is reclosed prior to completion of its opening stroke.

7 An automatic reclosing circuit breaker system comprising a source of gas pressure, a fluid motor, means operatively connecting said motor to the circuit breaker including trip-free means, a valve for controlling admission of gas from said source to said motor to cause closing of said circuit breaker, means for holding said circuit breaker in closed circuit position against an opening bias, fault responsive means coacting with said holding means for causing opening of said circuit breaker, means operable upon predetermined circuit opening movement of said breaker to cause opening of said valve for admitting gas from said source to the Working space of said motor whereby said circuit breaker is immediately reversed and reclosed prior to completion of its opening stroke, and pressure responsive means communicating with said motor working space for placing said circuit breaker under control of said trip-free means during the aforesaid closing and reclosing operations.

8. An automatic reclosing circuit breaker system comprising a source of gas pressure, a iiuid motor, means operatively relating said motor to the circuit breaker including trip-free means, a valve for controlling admission of gas from said source to said motor to cause closing of said circuit breaker, means for holding said circuit breaker in closed circuit position independently of said motor against an opening bias, fault responsive means coacting with said holding means for causing initial opening of said circuit breaker, means operable upon partial circuit opening movement of said breaker for admitting gas from said source to said motor whereby said circuit breaker is immediately reversed after said partial movement and reclosed, and pressure responsive means operable when said motor is supplied with gas pressure for placing said circuit breaker under control of said trip-free means during the aforesaid reclosing operation.

9. An automatic reclosing circuit breaker system comprising a source of gas pressure, a fluid motor having a piston arranged for reciprocal movement, means operatively connecting the piston rod of said piston to the circuit breaker, a lost-motion connection between said piston and said piston rod corresponding to a partial opening stroke, a valve for controlling admission of gas lfrom said source to said piston to cause closing of said circuit breaker, means for holding said circuit breaker independently of said piston in closed circuit position against an opening bias, means for presetting said piston at a point corresponding to said partial opening stroke, fault responsive means coacting with said holding means for causing initial opening of said circuit breaker independently of said piston to take up said lostmotion, and means operable upon said partial circuit breaker opening movement to cause opening of said valve for admitting gas from said source to said piston whereby said circuit breaker is immediately reversed after said partial movement and reclosed.

10. An automatic reclosing circuit breaker system comprising a source of gas pressure, a fluid motor having a piston arranged for reciprocal movement, means including a mechanical lostmotion connection operatively connecting said piston to the circuit breaker, a valve for controlling admission of gas from said source to said piston to cause closing of said circuit breaker, means for holding said circuit breaker in closed circuit position independently of said piston against an opening bias, said piston thereby being permitted to preset through said lostmotion connection to a partially open position, fault responsive means coacting with said holding means for causing opening of said circuit breaker, said breaker after partial opening movement being in driving relation to said piston, and means operable upon said partial circuit breaker opening movement to cause opening of said valve vfor admitting gas from said source to said piston fault condition when said circuit breaker is normally closed, trip-free means for also tripping said circuit breaker when it is closed during a fault condition, and pressure-responsive means operable when pressure is applied to said uid motor for transferring the tripping control from said first-named tripping means to said trip-free means.

12. An automatic reclosing circuit breaker system comprising a fluid motor operable through a working stroke to close the circuit breaker, a source of uid pressure for operating said motor, means for presetting said motor after a working stroke independently of said circuit breaker at an intermediate point in said stroke, control means for admitting said fluid to said motor, tripping means for said circuit breaker, means operative in responsive to predetermined opening movement o said circuit breaker for admitting fluid to said motor and causing reversal of movement of said motor from said intermediate point to reclose said circuit breaker, and pressure responsive means connected to said motor for controlling said tripping means.

13. An automatic reclosing circuit breaker system' comprising asource of gas pressure, a fluid motor operable by said pressure, means operatively relating said motor to the circuit breaker for closing said circuit breaker, means for tripping said circuit breaker in response to a fault condition, trip-free means for also tripping said circuit breaker Whenit is closed duringa fault condition, and pressure-responsive means associatedwith said fluid motor for controlling the tripping of. said first-named trippingmeans and said trip-free means. v

14. An automatic reclosing circuit breaker sys.,-V tem comprising an operating piston, means including a trip-freeconnection and a lost-motion connection operatively relating said piston to said circuit breaker, said piston being biased to preset to an intermediate position through said lostmotion connection independently of said circuit breaker after the closing stroke, a source of fluid pressure for driving through said trip-free connection said piston through a working stroke to cause closing movement of said circuit breaker, a control valve between said source and piston,

means for initiating opening movement of said.

circuit breaker independently of said trip-free connection, reolosing means operable in response to predetermined opening movement of said circuit breaker for opening said valve to start said piston from its preset position so that the circuit breaker is reclosed prior to completion of the opening stroke thereof, means for releasing said trip-free connection for causing opening of said circuit breaker in the event that said reclosing operation is concurrent with a circuit fault, and means responsive to fluid pressure at said piston for controlling the aforesaid trip-free connection.

- l15. An automatic reclosing circuit breaker sys-f tem comprising a source of gas pressure, a uid motor having a cylinder and piston, an operating trip-free linkage interposed with respect to said piston and the circuit breaker, a lost-motion connection between said piston and operating linkage, a valve for controlling admission of gas from said source to said cylinder so as to produce a working stroke of said piston for closing said circuit breaker, said piston being biased for independent movement through said lost-motion connection to preset at an intermediate point in said stroke after closing of said breaker, fault admitting gas to the working space of said motorY responsive means for releasing said .linkage and causing opening of said circuit breaker for take' ing up the lost-motion with said piston, and means operable in response to'predetermined circuit opening movement of said breaker to causeopening of said valve for admitting gas under pressure directly to the cylinder Working space 'so that said piston is moved through a fraction of itsk Working stroke and said circuit breaker is reclosed prior to completion of its opening stroke.

16. An automatic reclosing'circuit breaker system comprising a source of gas pressure, a fluid motor, means operatively connecting said motor vto the circuit breaker including trip-free means,

whereby said circuit breaker is immediately reversed and reclosed prior to completion of its.

opening stroke, and pressure responsive means communicating with said motor Working space for placing said circuit breaker under control of' said trip-free means during the aforesaid closing and reclosing operations.

17. An automatic reclosing circuit breaker system comprising a source of gas pressure, a uid motor having a piston arranged for reciprocal movement, an operating linkage between the piston rod and the circuit breaker, means including a mechanical lost-motion connection intercon- 1 necting the piston rod and said linkage, a valve for controlling admission of gas from said source.

to Vsaid piston to cause closing of said circuit breaker, said piston when the breaker is closedl being biased to preset through said lost-motion connection to a partially open position, fault responsive means for causing opening of said circuit breaker, said breaker after partial opening movement being in driving relation to said piston, and means operable in response to said partial circuit breaker opening movement to cause opening of said valve for admitting gas from said source to-said piston so that said circuit breaker is immediately reversed and reclosed prior to completion of its opening stroke.

CARL THUMIM.