Patent Application
20170250039
The present invention relates to a gas circuit breaker adopting a double motion mechanism which drives electrodes in opposite directions to each other.
As a gas circuit breaker used for a high-voltage power system, a so-called puffer-type gas circuit breaker is generally used, which breaks electric current by using pressure increase of an extinguishing gas during an opening operation and by blowing a compressed gas to an arc generated between electrodes.
In order to improve circuit-breaking performance of the puffer-type gas circuit breaker, a double motion system in which an electrode on a driven side which has been fixed in related art is driven in an opposite direction of a driving direction of a drive-side electrode is proposed.
For example, a system using a fork-shaped lever is proposed in Patent Literature 1. In this invention, the fork-shaped lever rotates when a pin interlocked with the movement on a drive side touches a recess of the fork, and the rotation is converted into a reciprocating motion in a direction of an opening/closing shaft, thereby driving a driven-side arcing contact in an opposite direction of the driving direction of the drive-side electrode. In a state where the pin is separated from the recess of the fork, the lever maintains the position and the driven-side arcing contact is stationary.
An object of the invention is to move the driven side efficiently with the minimum driving force in a time domain necessary for breaking electric current.
Moreover, a double motion system using a grooved cam is proposed in Patent Literature 2. In this system, a pin moves inside the grooved cam in accordance with the movement of a drive side, and the cam is rotated to thereby drive a driven side arcing contact coupled to the cam in an opposite side of a drive side electrode. A desired speed ratio between the driven-side arcing contact and the drive-side electrode can be realized by forming the grooved cam in an arbitrary shape.
However, the shape of the fork-shaped lever described in Patent Literature 1 is formed only by a straight line portion and an arc portion, therefore, there is a problem that the speed on the driven side is not capable of being arbitrarily set. Moreover, as the pin touches the recess of the fork-shaped lever at every opening/closing operation, there is a danger that an excessive force is added to the fork-shaped lever.
Although the speed on the driven side can be arbitrarily set by the grooved cam in Patent Literature 2, the grooved cam has an approximately arc shape and the driven side constantly operates with respect to the movement on the drive side, therefore, it is difficult to limit the movement on the driven side to be performed in a desired time domain. Moreover, as the groove cam has the approximately arc shape, there is a problem that an apparatus is increased in size.
In a gas circuit breaker according to the invention, a drive-side electrode and a driven-side electrode are provided so as to face each other inside a sealed tank 100, the drive-side electrode has a drive-side main electrode 2 and a drive-side arcing contact 4, and the driven-side electrode includes a driven-side main electrode 3 and a driven-side arcing contact 5, the drive-side arcing contact 4 is connected to an actuator 1, and the driven-side arcing contact 5 is connected to a double motion mechanism section 10. The double motion mechanism section 10 includes a drive-side connecting rod 11 receiving a driving force from the drive-side electrode, a driven-side connecting rod 13 connecting to the driven-side arcing contact 5, two levers 12 operating the driven-side connecting rod 13 in an opposite direction with respect to an operation of the drive-side connecting rod 11, and a guide 14 in which the drive-side connecting rod 11 and the driven-side connecting rod 13 move thereinside, the two levers 12 are arranged on both sides of the guide 14, which are fixed to each other so as to rotate freely by a lever fixing member 15, a movable pin 18 is connected to a first grooved cam 16 formed in the drive-side connecting rod 11, a second grooved cam 17 formed in the guide and third grooved cams 19 formed in the two levers 12 respectively, and posture holding members 22 which hold the movable pin 18 so that the movable pin 18 is approximately orthogonal to an opening/closing operation shaft of a circuit breaker part are provided.
According to the invention, shapes of grooved cams which can minimize energy of the actuator while securing the circuit breaking performance can be realized, and operation energy can be reduced as compared with a related-art double motion system. Moreover, a space saving and reliable double motion mechanism can be realized.
Hereinafter, a gas circuit breaker according to an embodiment of the invention will be explained with reference to the drawings. The following is just an embodiment, which does not intend to limit the contents of the invention to the following specific examples. The invention itself can be achieved in various manners so as to correspond to the contents described in claims. In the following embodiment, a circuit breaker having a mechanical compression chamber and a thermal expansion chamber is explained as an example, however, the invention of the present application may be applied to, for example, a circuit breaker having only the mechanical compression chamber.
In a gas circuit breaker according to an embodiment of the invention, a first grooved cam including an arbitrary curved portion and a straight line portion is drilled in a rod connecting to a drive side, a second grooved cam in which a movable pin functions as a stopper for suppressing movement of a driven side when the movable pin exists in the straight line portion and the movable pin functions as a guide for movement of the pin when the movable pin exists in the curved portion is drilled in guide plates which sandwich the driven-side connecting rod from both sides, the movable pin is inserted into grooves cut in two levers having the same shape provided on outer sides of the guide plates and posture holding members suppressing rotation of the movable pin around two axes perpendicular to a pin axis are provided on both ends of the movable pin so that a speed ratio between the drive side and the driven side is variable as well as intermittent driving is possible, in which the levers rotate with movement of the movable pin to thereby move the driven-side electrode in an opposite direction of the drive side.
A drive electrode and a driven electrode are coaxially provided so as to face each other inside a sealed tank 100. The drive-side electrode includes a drive-side main electrode 2 and a drive-side arcing contact 4, and the driven-side electrode includes a driven-side main electrode 3 and a driven-side arcing contact 5.
An actuator 1 is provided adjacent to the sealed tank 100. A shaft 6 is coupled to the actuator 1, and the drive-side arcing contact 4 is provided at a tip end of the shaft 6. The shaft 6 and the drive-side arcing contact 4 are provided so as to penetrate inside a mechanical compression chamber 7 and a thermal expansion chamber 9.
The drive-side main electrode 2 and a nozzle 8 are provided on a circuit breaker part side of the thermal expansion chamber 9. The driven-side arcing contact 5 is provided so as to face the drive-side arcing contact 4 on the same axis. One end of the driven-side arcing contact 5 and a tip portion of the nozzle 8 are connected to a double motion mechanism section 10.
As shown in
When breaking a short-circuit current due to lightning, the actuator 1 is driven in an opening direction to separate the drive-side main electrode 2 from the driven-side main electrode 3 through the shaft 6. At this time, an arc is generated between the drive-side arcing contact 4 and the driven-side arcing contact 5. The arc is extinguished by mechanical blowing of an extinguishing gas by the mechanical compression chamber 7 and blowing of the extinguishing gas using arc heat by the thermal expansion chamber 9, thereby breaking electric current.
In order to reduce operation energy of a puffer-type gas circuit breaker, the double motion mechanism section 10 which drives the driven-side arcing contact which has been fixed in related art in an opposite direction of a driving direction of a drive-side electrode is provided. Hereinafter, a double motion system according to the embodiment of the invention will be explained with reference to
The double motion mechanism section 10 according to the invention is configured by connecting a driven-side connecting rod 13 and a drive-side connecting rod 11 by levers 12 provided in a guide 14 so as to rotate freely while holding the driven-side connecting rod 13 and the drive-side connecting rod 11 by the guide 14 in a direction of breaking operation so as to move freely.
A first grooved cam 16 is drilled in the drive-side connecting rod 11, which has a second straight line portion 16C, a connecting portion 16B and a first straight line portion 16A seen from the actuator side. The first straight line portion 16A and the second straight line portion 16C are arranged on different axis lines from each other, and the connecting portion 16B is provided therebetween.
The first grooved cam 16 is formed so that a displacement width thereof in a vertical direction falls within a displacement width of a second grooved cam 17 in the vertical direction and a displacement width of a third grooved cam 19 in the vertical direction. A shape of the connecting portion 16B may be arbitrarily designed in accordance with operation characteristics of a circuit breaker part, and for example, a curve or a straight line can be considered.
As displacement of the drive-side connecting rod 11 in the vertical direction is limited by a groove (30 in
A second grooved cam 17 which is equal to a width of the first grooved cam 16 in the vertical direction and is formed in a curve is drilled in the guide 14 as shown in
Moreover, the movable pin 18 is inserted to the third grooved cam 19 drilled in the lever 12, and the lever 12 rotates around a lever fixing pin 15 as a rotation axis. At this time, the movable pin 18 moves while rolling in the second grooved cam 17 in one direction when moving on the connecting portion 16B of the first grooved cam. Due to the movement of the movable pin 18 in one direction, a force acts on one side of an inner wall of the third grooved cam 19, which limits a rotation direction of the lever 12. The shape of the third grooved cam 19 is not particularly limited and can be appropriately changed in accordance with the breaking operation characteristics.
A driven-side moving pin 20 attached to the lever 12 transmits the force to a guide groove 21 drilled in the driven-side connecting rod 13 by the above rotating motion, thereby driving the driven-side connecting rod 13 connecting to the driven-side arcing contact 5 in an opposite direction to the drive-side connecting rod 11.
As displacement of the driven-side connecting rod 13 in the vertical direction is limited by a groove (31 in
The connection between the double motion mechanism section 10 and the drive side is performed by, for example, attaching a fastening ring 23 in the nozzle 8 and providing a hole through which a tip portion of the drive-side connecting rod 11 penetrates in the fastening ring 23 to thereby fasten a drive-side fastening screw 24 by a nut.
Two levers 12 are attached to the outside of the guide 14 in the same shape. The movable pin 18 penetrates through the second grooved cam 17 in the guide 14, the first grooved cam 16 in the drive-side connecting rod 11 and the third grooved cams 19 in the levers 12. The movable pin 18 is not fixed to any portion and can move freely in respective grooves. However, rotations around two axes orthogonal to an axis of the movable pin can occur as the degree of freedom in operation is high. Due to the rotations, abutting manners between the pin and three kinds of grooves vary on right-and-left both sides in
The driven-side moving pin 20 penetrates through the levers 12 (lever driven-side holes 28) and the driven-side connecting rod 13 (the guide groove 21), which is fixed by moving pin fastening nuts 27 from both sides.
The lever fixing pin 15 is provided with fixing rings 25 on both ends to prevent falling off from the guide 14.
A length of a cylindrical portion of the movable pin 18 is set to be longer than a thickness of the levers 12 and the guide 14 in the stacked direction so that the movable pin 18 can move freely in the grooved cam.
As the lever fixing pin 15 is constantly stationary during the operation and is not necessary to be firmly fastened by a bolt/nut, the fixing rings are attached, however, the lever fixing pin 15 may be fastened by nuts in the same manner as the movable pin 18 and the driven-side moving pin 20.
The driven-side moving pin 20 penetrates through the lever driven-side holes 28 and the guide groove 21, however, it is also preferable that the lever 12 has a long hole and the driven-side connecting rod 13 has a circular hole.
On the other hand, when the both ends of the movable pin 18 are pressed by the posture holding members 22 according to the invention, an inner surface of the posture holding member 22 touches an outer surface of the lever 12 and a force to return the pin to the original posture acts even if the movable pin 18 is inclined, therefore, the inclination of the lever 12 is suppressed and the breaking does not occur.
When the posture holding member is formed as a circular washer-type, a relation shown in
The case where the posture holding members are formed as the circular washer type has been explained, however, a rectangular washer type can be also adopted. The shape of the posture holding members is not particularly limited as long as an axis of the movable pin 18 is held in a state of being approximately orthogonal to the opening/closing operation shaft of the circuit breaker part by holding the posture holding members 22 touched to both ends of the levers 12, however, it is preferable to adopt a thin flat-plate shape in consideration of size reduction. When considering the size reduction, the posture holding members 22 are preferably fixed to both ends of the movable pin 18. A structure in which the posture holding members 22 are integrally formed on both ends of the movable pin 18 can be considered.
In the embodiment, the first grooved cam 16 and the second grooved cam 17 overlap each other in the axial direction of the movable pin 18 as shown in
Moreover, as the degree of freedom in designing the first grooved cam is high, the design change can be easily performed in accordance with kinds of machines having different structures of the circuit breaker part and circuit breaking systems, and the optimum curved shape to secure the circuit breaking performance can be designed. As the length and the area of the straight line portion can be set freely, the driven side can be moved only in an arbitrary time domain.
The above operation is especially effective for breaking a small capacitive current. It is necessary that a breakdown voltage between electrodes in each time of circuit breaking exceeds a recovery voltage in the small capacitive current breaking. That is because it is necessary to secure a distance between electrodes as long as possible at a short period of time as the breakdown voltage between electrodes depends on the distance between electrodes at each time.
The shapes of the grooved cams of the double motion mechanism which can realize stroke characteristics necessary for breaking the small capacitive current have been shown in the embodiment, however, the optimum stroke characteristics exist with respect to various types of breaking duties, and these can be realized by changing the shape of the connection portion 16B formed by an arbitrary curve in the embodiment.
A speed ratio of the driven-side operation with respect to the drive-side operation can be changed by adjusting the positional relation among the first straight line portion 16A, second straight line portion 16C, connecting portion 16B of the first grooved cam, the second grooved cam 17 and the third grooved cams 19.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-033739 | Feb 2016 | JP | national |
