JPH0822751A - Vacuum valve - Google Patents

Abstract

PURPOSE:To stabilize breaking capacity regardless of an arc generating point at electric current breaking time by providing current-carrying parts in parts where an angle formed by grooves arranged on a side surface of an electrode and a contactor side end surface of a cylindrical electrode is an acute angle. CONSTITUTION:A movable electrode 3B is installed on the tip of a movable current-carrying shaft 5B, and a layer composed of current-carrying parts 21a to 21d and insulating parts 8a to 8d is arranged in a front part of the electrode 3B. A contactor 4B is fixed to the front surface, and grooves 6a to 6d are formed in a cylinder part of this electrode 3B, and are formed so as to continue with grooves 7a to 7d formed in a bottom part. Between the cylinder part of the electrode 3B and the contactor 4B, Current-carrying parts 21a to 21d are arranged in parts on the side where an angle formed by the grooves 7a to 7d and a cylinder part end surface is an acute angle, and a part except it becomes the insulating parts 8a to 8d. Then, an electric current flows to the contactor 4B from the movable current-carrying shaft 5B through the cylinder part. This electric current has a circumferential directional component, and generates a sufficient axial directional magnetic field, and stable and excellent breaking performance is obtained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to vacuum valves.

[0002]

2. Description of the Related Art FIG. 3 is a vertical sectional view of a conventional vacuum valve having a vertical magnetic field electrode incorporated in a vacuum circuit breaker.
4 is a sectional view taken along line BB of FIG. As shown in FIGS. 3 and 4, the conventional vacuum valve allows the fixed electrode 13A and the movable electrode 13B to come into contact with and separate from each other in a vacuum container in which both ends of the insulating cylinder 1 are sealed by the fixed flange 2A and the movable flange 2B. It is arranged.

Of these, the fixed electrode 13A is fixed to the tip of a fixed current-carrying shaft 5A which penetrates the fixed flange 2A, and a contactor 4A is coupled to the front surface of the fixed electrode 13A so as to be fixed to the outside of the vacuum vessel. It is connected by a shaft 5A. on the other hand,
The movable electrode 13B is a guide tube penetrating the movable flange 2B.
It is fixed to the tip of the movable energizing shaft 5B penetrating 10 and the contactor 4B is coupled to the front surface of the movable electrode 13B, and is connected to the outside of the vacuum container by the movable energizing shaft 5B. The intermediate portion of the movable energizing shaft 5B is supported by the movable flange 2B via the bellows cover 15 and the bellows 9 and is connected to the lower end of the movable energizing shaft 5B while maintaining the vacuum in the vacuum container. An operation mechanism portion (not shown) via the insulating rod enables energization and interruption by contact and separation with the fixed electrode 13A. A cylindrical arc shield 14 is attached to the inner surface of the insulating cylinder 1.

By the way, since the vacuum valve utilizes the excellent dielectric strength of vacuum, the distance between the electrodes can be shortened as compared with, for example, an SF ₆ gas circuit breaker using another insulating medium, and the outer shape can be reduced. Can be made small. Also, the breaking capacity can be increased by changing the configuration of the electrodes. On the other hand, in order to improve the breaking performance of the vacuum valve, it is necessary to suppress the local heating of the electrodes due to the arc generated between the electrodes. That is, the blocking performance can be improved by suppressing the generation of abnormal charged particles and the generation of metal vapor due to local heating of the electrode. The electrode structure for this is as follows:
A method of applying an electromagnetic force with a magnetic field is common.

As one of the application directions of the magnetic field, there is a method of applying a perpendicular magnetic field to the arc generated between the electrodes. The electrodes adopting this method are generally called spiral electrodes and contract electrodes, but the magnetic field generated by such electrodes is a magnetic field radial from the axial center of the electrodes. Therefore, since the magnetic field is orthogonal to the arc generated between the electrodes, Lorentz force acts on the arc in the circumferential direction. As a result, the arc is rotationally driven in the circumferential direction, and by moving the electrode surface, it is possible to prevent the aforementioned generation of particles and vapor due to local melting of the electrode due to local heat input.

In a vacuum valve incorporated in a vacuum circuit breaker applied to a high voltage circuit, it is necessary to increase the distance between the electrodes in order to increase the withstand voltage value between the electrodes.
In the above electrode structure in which a magnetic field perpendicular to the arc generated between the electrodes is applied, when the arc rotates on the surface of the electrode, the arc may be stretched in the circumferential direction and may be radially ejected from the electrode. In this case, there is a risk that the arc will ignite the arc shield mounted around the electrode, in which case the arc will stagnate at the ignition part,
Excessive heat input is generated locally. If the electrode and the arc shield are melted by this excessive heat input, the breaking performance is deteriorated. Further, in this electrode structure, as described above, since the arc state is a concentrated arc and the temperature is high, the wear of the contacts is accelerated, and the switching life at the time of large current interruption is shortened.

As another method of applying a magnetic field to the arc generated when the current is cut off, there is a method of applying a magnetic field in the axial direction parallel to the arc generated between the electrodes. In this so-called longitudinal magnetic field electrode, the arc generated between the electrodes spreads evenly over the entire electrode, preventing local excessive heat input of the electrode and making it an electrode with excellent blocking performance. . Further, even when the distance between the electrodes is increased with respect to the high voltage, a stable arc can be ignited between the electrodes by optimizing the strength of the magnetic field, and the breaking performance can be improved. Furthermore, since the arc form is an arc dispersed over the entire electrode, the contactor is not consumed even when a large current is interrupted, and the switching life can be extended.

Here, the electrode structure of a conventional vacuum valve for generating an axial magnetic field will be described. As shown in FIG. 4, a coil electrode is provided, and an electric field flowing in the coil electrode generates an axial magnetic field between the electrodes. The current flowing through this coil electrode is 4 formed radially from the center.
The current is divided into the arm portions 13a of the book, flows from the tip of each arm portion 13a to the arc-shaped coil portion 13b, and further flows from the tip portion 13c of the coil portion to the contact. This coil electrode is attached to both the movable electrode side and the fixed electrode side, and a magnetic field in the axial direction is generated between the electrodes by the current flowing in the coil portion. In FIG. 4, the arm portion 13a is 4
Although the case of division is shown, the strength of the magnetic field in the axial direction can be changed by changing the number of divisions.

However, in such an electrode structure, the current path becomes long and the resistance becomes large, which may adversely affect the current-carrying performance. In order to reduce the resistance, it is conceivable to make the coil electrode thicker or increase the number of coil electrode divisions, but the magnetic field strength in the axial direction generated between the electrodes is reduced, and sufficient blocking is performed. There was a case where the performance was not obtained. Further, the structure is complicated and the electrodes are large, which causes various problems in manufacturing a vacuum valve, which may reduce reliability.

On the other hand, as another electrode structure for generating an axial magnetic field with a simpler structure, as shown in Japanese Patent Publication No. 3-59531, a spiral groove is formed in the cylindrical portion of a cup-shaped electrode. There is something I did. In this electrode, by making the current path of the cylindrical portion spiral, an arc-shaped component of the current is generated, thereby generating a magnetic field in the axial direction between the electrodes. With this configuration, the strength of the magnetic field in the axial direction can be changed by changing the inclination of the groove of the cylindrical portion.

[0011]

However, in the case of such a cup-shaped electrode, the joint between the electrode and the contact extends over the entire surface between the grooves which are the end faces of the cylindrical portion.
The current path in the electrode changes depending on the position of the arcing point when the current is cut off. Therefore, the strength of the generated axial magnetic field becomes unstable. For example, as shown in FIG. 5, when the current path takes the path indicated by the arrow B, a circumferential component of the current that can generate a sufficient axial magnetic field is generated, but the path indicated by the arrow C. When the above is taken, a sufficient circumferential component of the electric current is not generated, so that the axial magnetic field generated is also weakened. That is, the blocking performance is reduced. The object of the present invention is, regardless of the arc firing point at the time of current interruption,
It is to provide a vacuum valve having stable and excellent shutoff performance.

[0012]

In order to achieve the above-mentioned object, the present invention is to provide at least one of a pair of electrodes which are provided in a vacuum container and which have a contactor on the opposite surface and which can be separated from each other, in a cylindrical shape. In a vacuum valve as an electrode, having a plurality of grooves formed on the side surface of the cylindrical electrode formed in a direction oblique to the axis, and a current-carrying portion provided between the cylindrical electrode and the contact, The gist is that a current-carrying portion is provided in a portion where an angle formed between the groove and the end surface of the cylindrical electrode on the contactor side is acute.

[0013]

In such a structure, the current path from the cylindrical electrode to the contactor is determined to be the path from the groove provided on the side surface of the cylindrical electrode to the contactor via the current-carrying portion, and the arc at the time of current interruption It is possible to obtain a sufficient current circumferential component for generating an axial magnetic field, regardless of the ignition point.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the description is omitted because it is the same as the conventional one except the electrode part. 1 is a plan view of a movable electrode of a vacuum valve showing an embodiment of the present invention, and FIG. 2 is a front view of FIG. In these figures, the movable electrode 3B is attached to the tip of the movable energizing shaft 5B, and the energizing portions 21a, 21b, 21c, 21d and the insulating portions 8a, 8 are provided on the front surface of the movable electrode 3B.
A layer composed of b, 8c, and 8d is provided, and a contactor 4b is fixed to the front surface thereof. Further, grooves 6a, 6b, 6c, 6d are formed in the cylindrical portion of the cup-shaped movable electrode 3B, and grooves 7a, 7b, 7c, 7d formed on the bottom are formed.
Is formed so as to be continuous with. In the present embodiment, the case where there are four grooves is shown.

Between the cylindrical portion of the electrode 3B and the contactor 4B, current-carrying portions 21a, 21b, 21c and 21d are provided on the side where the angle formed by the grooves 7a, 7b, 7c and 7d and the end face of the cylindrical portion is acute. Insulating part 8 is provided between the end face of the other cylindrical part and the contactor.
a, 8b, 8c, 8d.

Next, the flow of current will be described. The electric current flows from the movable energizing shaft 5B through the grooves 6a, 6b, 6c, 6d at the bottom of the electrode in an arc shape to reach the cylindrical portion, and the groove 7 of the cylindrical portion is formed.
a, 7b, 7c, 7d and the insulating parts 8a, 8b, 8c, 8d provided between the electrode 3B and the contactor 4B, the contactor passes through the current-carrying parts 21a, 21b, 21c, 21d as shown by arrow A. It flows to 4B. As a result, a circumferential component is generated as a directional component of the current, and an axial magnetic field is generated. And
A current flows from the contactor 4B through the arc generated in the vacuum to the opposing contactor 4A on the fixed side, and the fixed electrode also has a similar structure and a similar current flow.

As described above, according to this embodiment, the current path is limited to the grooves 6a to 6d, 7a to 7d and the insulations 8a to 8d, so that the current always passes through the current-carrying portions 21a to 21d. Therefore, a sufficient circumferential component is always generated, a sufficient axial magnetic field can be generated regardless of the position of the arc ignition point, and stable and excellent breaking performance can be obtained.

The grooves 6a, 6b, 6c, 6 at the bottom of the electrode
Although d may not be provided, the magnetic field strength in the axial direction can be further increased by providing this groove. Further, if the resistivity of the insulating portions 8a to 8d is 40 times or more the resistivity of the conducting portions 21a to 21d, the current mainly flows through the electrode member, so that a larger magnetic field strength in the axial direction can be obtained. it can.

The vacuum valve according to the present invention is not limited to the above embodiment. As a second embodiment, the grooves 6a,
Members 6b, 6c, 6d, 7a, 7b, 7c, and 7d whose resistivity is 40 times or more that of the electrode member, for example, stainless steel may be inserted when the electrode member is copper. According to this embodiment, since the member inserted in the groove has a higher resistivity than the electrode, the current mainly flows through the electrode member, and the axial magnetic field is generated in the same current path as in the above embodiment. become. Moreover, since the member is inserted into the groove, the mechanical strength of the electrode can be increased.

As a third embodiment, assuming that the area of the contactor side front surface of the electrode cylinder is S and the number of grooves is n, the energization part between the contactor and the electrode is the electrode cylinder contactor side. The area occupying the front part should be 0.1 × S / n or more and 1/2 or less. By forming the current-carrying part in this range, sufficient breaking performance can be obtained, and sufficient current-carrying capacity and mechanical strength of the current-carrying part can be secured with respect to the current-carrying performance which is preferable as the resistance value of the electrode part is smaller. .

[0021]

As described above, according to the present invention, a vacuum valve in which at least one of a pair of electrodes which are provided in a vacuum container and which have a contactor on the opposite surface and which can be contacted and separated is a cylindrical electrode is used. In, there are provided a plurality of grooves formed on the side surface of the cylindrical electrode diagonally with respect to the axis, and a current-carrying portion provided between the cylindrical electrode and the contact, and the groove and the cylindrical electrode. Since the current-carrying portion is provided at the portion where the contact-side end face makes an acute angle, it is possible to obtain a vacuum valve with stable and excellent breaking performance.

[Brief description of drawings]

FIG. 1 is a plan view of a movable electrode of a vacuum valve showing an embodiment of the present invention.

FIG. 2 is a front view of a movable electrode of a vacuum valve showing an embodiment of the present invention.

FIG. 3 is a sectional view of a conventional vacuum valve.

FIG. 4 is a diagram for explaining a vertical magnetic field electrode of a conventional vacuum valve.

FIG. 5 is a view for explaining another vertical magnetic field electrode of the conventional vacuum valve.

[Explanation of symbols]

3B ... movable electrode, 8a, 8b, 8c, 8d ... insulating part, 21
a, 21b, 21c, 21d ... Current-carrying part.

Claims (5)

[Claims] 1. A vacuum valve having a cylindrical electrode, at least one of a pair of contactable and separable electrodes provided in a vacuum container and having a contactor disposed on an opposing surface, in a direction oblique to an axis. A plurality of grooves formed on the side surface of the cylindrical electrode and a current-carrying portion provided between the cylindrical electrode and the contactor, and the groove and the contactor side of the cylindrical electrode. A vacuum valve, wherein the energizing portion is provided in a portion where an angle formed by the end face is an acute angle. 2. The vacuum valve according to claim 1, wherein a groove that is continuous with a plurality of grooves provided on the side surface of the cylindrical electrode is formed in the bottom portion. 3. When the area of the contact side end surface of the cylindrical electrode is S and the number of grooves of the groove is n, the area occupied by the energizing portion on the contact side end surface of the cylindrical electrode is 0.1S / It is n or more and 1/2 or less, The vacuum valve in any one of Claim 1 or Claim 2 characterized by the above-mentioned. 4. The resistivity of the portion between the cylindrical electrode and the contact excluding the current-carrying portion is set to 40 times or more the resistivity of the current-carrying portion. The vacuum valve according to any one. 5. The resistivity of the cylindrical electrode member is set in the groove.
The vacuum valve according to any one of claims 1 to 4, wherein a member having a resistivity of 40 times or more is inserted.