JP2000268684A - Switchgear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switchgear prevented from being deteriorated in withstand voltage performance. SOLUTION: This switchgear is equipped with a disk-shaped fixed contact 6, a movable contact 10 making contact with/separating from the disk-shaped fixed contact 6, an electric-field relaxing member 7 disposed around the fixed contact 6 with its portion around the fixed contact 6 projecting beyond the fixed contact 6 to the movable contact 10 side, an electric-field relaxing shield 11 disposed around the movable contact 10 and having a portion that projects beyond the movable contact 10 to the fixed contact 6 side when the movable contact 10 is at a separated position, and a vacuum container 1 for housing the fixed contact 6, the movable contact 10, the electric-field relaxing member 7, and the electric-field relaxing shield 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switchgear having a circuit opening / closing section in a vacuum vessel maintained in a high vacuum and opening / closing a circuit between a power supply and a load device, and particularly to a switchgear having reduced withstand voltage performance. The present invention relates to a switchgear for preventing

[0002]

2. Description of the Related Art A switchgear for opening and closing a circuit between a power supply and a load device has a circuit opening / closing portion inside a vacuum vessel maintained in a high vacuum, and has a high dielectric strength in a high vacuum and excellent performance. By utilizing the arc extinguishing ability, the current is cut off stably.

FIG. 5 is a vertical sectional view showing a conventional switch gear. In the figure, reference numeral 1 denotes a vacuum vessel, and the vacuum vessel 1 has both ends of a cylindrical insulating tube 2 constituting a side portion sealed by a lower cover plate 3 and an upper cover plate 4 so as to maintain a high vacuum inside. Container. Vacuum container 1 in the center of lower side cover plate 3
A fixed conductor rod 5 having a columnar shape is fixed so as to penetrate inside and outside of the fixed conductor rod 5. The fixed conductor rod 5 inside the vacuum vessel 1 has a disk shape on the upper surface and has a diameter similar to that of the fixed conductor rod 5. The fixed contact 6 is brazed via a metal bonding material 7, and the edge of the upper surface of the fixed contact 6 is chamfered to have a curved surface to prevent concentration of an electric field.

[0004] The vacuum vessel 1 passes through the center of the upper cover plate 4.
The cylindrical movable conductor rod 8 penetrating inside and outside of the
It is supported movably in the axial direction via a bellows 9 having a bellows shape which can be stretched and sealed inside. At the lower end of the movable conductor rod 8 inside the vacuum vessel 1, a lower surface is formed in a disk shape facing the upper surface of the fixed contact 6, and the movable conductor rod 8
The movable contact 10 having the same diameter as that of the movable contact 10 is fixed in an inserted state, and the edge of the lower surface of the movable contact 10 is chamfered to have a curved surface to prevent concentration of an electric field.

The upper end of the bellows 9 is hermetically sealed to the upper cover plate 4 of the vacuum vessel 1, covers the movable conductor rod 8, and the lower end exposes the lower part of the movable conductor rod 8 to a suitable length. Since the movable conductor rod 8 expands and contracts with the linear movement of the movable conductor rod 8 in the axial direction, the airtightness of the vacuum vessel 1 can be maintained. The bellows 9 has a cylindrical shape with a bottom and is made of a low-conductivity material such as stainless steel.
, And is protected from metal vapor caused by an arc generated between the fixed contact 6 and the movable contact 10. The bottom of the bellows cover 13 is a bellows 9
And is supported by a movable conductor rod 8 penetrating the center of the bottom surface. The side of the bellows cover 13 holds the upper cover plate 4 when the movable conductor rod 8 moves upward.
It is long enough not to touch

In the conventional switchgear formed in this way, the upper surface of the fixed contact 6 and the lower surface of the movable contact 10 are located opposite to each other, and the movable contact 8 moves downward when the movable conductor rod 8 moves downward. The contact 10 comes into contact with the fixed contact 6 to close the switchgear. When the current is interrupted by linearly moving the movable conductor bar 8 upward to separate from the closed state to the open state, the fixed contact 6 and the movable contact 10
During the arc, an arc is generated, and the arc is opened after the arc is extinguished.

[0007]

However, in a conventional switchgear, the contact surface between the fixed contact 6 and the movable contact 10 is caused by an arc generated between the fixed contact 6 and the movable contact 10 when the current is interrupted. Wear and the contact surface becomes rough and sharp.

Further, when the contact surface is roughened and closed and energized, the resistance of the contact portions of the fixed contact 6 and the movable contact 10 becomes high due to the presence of the point, so that high heat is generated. When the contact portion is melted and then opened, the contact surface is further roughened to form a point.

An electric field concentrates on the apex protruding from the fixed contact 6 and the movable contact 10 formed as described above, so that there is a problem that the withstand voltage performance is reduced.

[0010] Further, since the foot of the arc is likely to stop due to the concentration of the electric field, local wear occurs, and a vicious cycle in which the contact surface is roughened is repeated.

The present invention has been made in view of such circumstances, and has a withstand voltage by providing an electric field relaxation member protruding from a fixed contact or a movable contact around a fixed contact or a movable contact, respectively. The main purpose is to provide a switchgear that prevents performance degradation.

Further, the fixed contact has a disk shape having a diameter larger than that of the fixed contact, and has an electric field relaxation member sandwiched between the fixed contact and the fixed conductor rod. It has a cylindrical shape having a diameter larger than that of the contact and the movable conductor rod, and is provided with an electric field relaxation member disposed around the movable contact and the movable conductor rod. Another object of the present invention is to provide a switchgear that prevents a decrease in withstand voltage performance without increasing the number of parts.

[0013]

According to a first aspect of the present invention, there is provided a switchgear having a fixed contact, a movable contact which comes into contact with / separates from the fixed contact, and a second contact protruding from the fixed contact to the movable contact. (1) An electric field relaxation member, and a second electric field relaxation member protruding from the movable contact side to the fixed contact side.

A switchgear according to a second aspect of the present invention includes a fixed contact, a movable contact that comes into contact with and separates from the fixed contact, and a switch gear that is disposed around the fixed contact and protrudes from the fixed contact toward the movable contact. A first electric field relaxation member, and a second electric field relaxation member disposed around the movable contact and projecting toward the fixed contact from the movable contact when the movable contact is at the separated position. It is characterized by.

[0015] The switchgears of the first and second inventions are:
By providing an electric field relaxation member protruding from the fixed contact and the movable contact around the fixed contact and the movable contact, respectively, the contact surface of the fixed contact and / or the movable contact becomes rough and a point is formed. Even in this case, the concentration of the electric field on each of the apexes can be reduced, and a decrease in withstand voltage performance can be prevented.

According to a third aspect of the present invention, there is provided a switch gear comprising a disk-shaped fixed contact, a movable contact which linearly moves in contact with / separates from the fixed contact, and a disk-shaped having a larger diameter than the fixed contact. Or a first electric field relaxation member which is annular and is fixed to the fixed contact, and a portion around the fixed contact protrudes from the fixed contact toward the movable contact, and a cylindrical member having a diameter larger than the movable contact. Is arranged around the movable contact, and when the movable contact is in the separated position,
A second electric field relaxation member having a portion protruding from the movable contact toward the fixed contact, and a container accommodating the fixed electric contact, the movable contact, the first electric field relaxation member, and the second electric field relaxation member. Features.

The switchgear according to a third aspect of the present invention is configured such that, on the fixed contact side, the switchgear has a disk shape having a diameter larger than the fixed contact, and includes an electric field relaxation member sandwiched between the fixed contact and the fixed conductor rod. On the movable contact side, a conventional switchgear component is formed by forming a cylindrical shape having a diameter larger than that of the movable contact and the movable conductor bar, and by providing an electric field relaxation member arranged around the movable contact and the movable conductor bar. For example, since the bellows cover is deformed or replaced, the number of parts is not increased, and even when the surface of the fixed contact and / or the movable contact becomes rough and a point is formed, an electric field is applied to each point. Since the concentration is reduced, it is possible to prevent a decrease in withstand voltage performance.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments. 1 and 2 are vertical sectional views showing a switchgear according to the first embodiment of the present invention. FIG. 1 shows an open state and FIG. 2 shows a closed state. In the figure, reference numeral 1 denotes a vacuum vessel, and the vacuum vessel 1 is formed by connecting both ends of a cylindrical insulating tube 2 constituting a side portion to a lower side cover plate 3,
And a container sealed by the upper side cover plate 4 so as to keep the inside at a high vacuum.

A cylindrical fixed conductor bar 5 is fixed to the center of the lower cover plate 3 so as to penetrate the inside and outside of the vacuum vessel 1. The diameter is formed to be larger than other parts.

At the center of the upper surface of the fixed conductor bar 5, a fixed contact 6 formed in a disc shape having a diameter smaller than the diameter of the upper portion of the fixed conductor bar 5 is formed in a disc shape having a recessed center portion. Is brazed via a metal bonding material 7 formed to have a diameter approximately equal to the diameter of the upper portion of the fixed conductor bar 5, and the edge of the upper surface of the fixed contact 6 is curved to prevent concentration of an electric field. Beveled to be. In addition, around the fixed contact 6,
That is, the edge of the metal bonding material 7 is formed so as to protrude above the fixed contact 6, and the fixed contact 6 is buried in the recessed central portion of the metal bonding material 7. The edge protruding upward of the metal bonding material 7 is also chamfered so as to have a curved surface to prevent concentration of an electric field. Since the cross section of the metal bonding material 7 is concave as described above, the concentration of the electric field near the embedded fixed contact 6 is reduced.

The vacuum vessel 1 passes through the center of the upper lid plate 4.
The cylindrical movable conductor rod 8 penetrating inside and outside of the
It is supported movably in the axial direction via a bellows 9 having a bellows shape which can be stretched and sealed inside. At the lower end of the movable conductor rod 8 inside the vacuum vessel 1, a movable contact 10 having a disk shape and having a diameter substantially equal to the diameter of the movable conductor rod 8 is fixedly inserted and fitted. The edge of the lower surface of 10 is chamfered so as to be curved to prevent concentration of the electric field.

The upper end of the bellows 9 is hermetically sealed to the upper cover plate 4 of the vacuum vessel 1, covers the movable conductor rod 8, and the lower end exposes the lower part of the movable conductor rod 8 to an appropriate length. Since the movable conductor rod 8 expands and contracts with the linear movement of the movable conductor rod 8 in the axial direction, the airtightness of the vacuum vessel 1 can be maintained.

Around the bellows 9, a cylindrical electric field relaxation shield 1 having a diameter that does not contact the bellows 9.
1 is arranged with the upper end fixed to the upper side cover plate 4,
The lower end of the electric field relaxation shield 11 is bent inward like an inner flange. As described above, the lower end of the electric field relaxation shield 11 has a planar shape having an opening at the center, and the diameter of the opening is formed to be slightly larger than the diameters of the movable conductor rod 8 and the movable contact 10. Are bent upward to prevent concentration of the electric field. And electric field relaxation shield 1
The side wall 1 is formed to have such a length as to protrude from the movable contact 10 toward the fixed contact 6 when the movable conductor rod 8 is at the upper limit of the movable range. The electric field relaxation shield 11 is made of a low-conductivity material such as stainless steel, and is formed so as to have a curved portion by a processing method such as drawing and pressing in order to prevent concentration of an electric field. In addition, the electric field relaxation shield 11 also has a function of protecting the bellows 9 from metal vapor generated by an arc similarly to the bellows cover 13 of the conventional switchgear. The score does not increase.

In the switch gear of the present invention thus formed, since the upper surface of the fixed contact 6 and the lower surface of the movable contact 10 are arranged to face each other, the movable conductor rod 8 moves downward. In this case, the movable contact 10 is
And the electrode is closed. Further, when the movable conductor bar 8 is linearly moved upward so as to move away from the closed state to the opened state to cut off the current, an arc is generated between the fixed contact 6 and the movable contact 10 to extinguish the arc. It becomes a closed state afterwards.

When the movable conductor rod 8 is at the upper limit of the movable range, the distance d1 between the fixed contact 6 and the movable contact 10 is determined by the upper end of the metal bonding material 7 and the electric field relaxation shield 11
Is longer than the distance d2 between the lower ends of. Further, the arc generated between the fixed contact 6 and the movable contact 10 when the current is interrupted, and the contact surface of the fixed contact 6 and the movable contact 10 caused by the heat generated by the energization cause the contact surface to be fused. Even when a rough peak is formed, the distance between each of the fixed contact 6 and the movable contact 10 is the distance between the protruding end of the metal bonding material 7 and the other end of the electric field relaxation shield 11. It will not be shorter than d2. For this reason, the concentration of the electric field on each apex is reduced, and the electric field distribution between the contacts is made uniform.

Next, the results of a simulation will be described. FIG. 3 is a graph showing the results of a simulation performed on the present invention and the conventional switchgear, in which the vertical axis represents the calculated electric field at the time of applying a voltage, and the vicinity of the end of the contact of the conventional switchgear having a rough contact surface. It is plotted assuming that the calculated electric field is 100%.

In the figure, the symbol △ indicates the calculated electric field near the end of the contact having a rough contact surface. The calculated electric field of the switchgear of the present invention having the electric field relaxation shield is the conventional switchgear without the electric field relaxation shield. About 50% of the calculated electric field
It has become. In the figure, the circles indicate the calculated electric field at the center of the contact having a rough contact surface, and the calculated electric field of the switchgear of the present invention having the electric field relaxation shield is the calculated electric field of the conventional switchgear without the electric field relaxation shield. About 70%
It has become.

It is shown that the smaller the calculated electric field value, the higher the withstand voltage performance. According to the simulation result simulating the state where the contact surface is rough, the switch gear of the present invention has a higher withstand voltage performance than the conventional switch gear. Was high.

Embodiment 2 FIG. 4 is a vertical sectional view showing an open state of the switchgear according to the second embodiment of the present invention. In the second embodiment, the diameter of the fixed conductor bar 5 is fixed,
Instead of the metal bonding material 7 for burying the fixed contact 6, a disk-shaped fixed conductor rod-side electric field mitigation shield 12 having a larger diameter than the fixed contact 6 is provided.

The fixed conductor rod side electric field mitigation shield 12 is concentrically sandwiched between the upper surface of the fixed conductor rod 5 and the lower surface of the fixed contact 6, and surrounds the fixed contact 6, that is, on the fixed conductor rod side. Since the edge of the electric field relaxation shield 12 is formed so as to protrude from the fixed contact 6 toward the movable contact 8, the fixed contact 6 is buried in the recess at the center of the fixed conductor rod side electric field reduction shield 12. It is in a state of being left. The fixed conductor rod side electric field mitigation shield 12 is made of a low-conductivity material such as stainless steel. Is formed.

In the second embodiment of the present invention thus formed, by providing the fixed conductor rod-side electric field relaxation shield 12 which can be relatively easily formed, the fixed conductor rod 5 is formed into a shape having a constant diameter which can be easily formed. Can be Note that members corresponding to those in Embodiment 1 are given the same reference numerals and description thereof is omitted.

[0032]

As described in detail above, in the switchgear according to the present invention, around the fixed contact and the movable contact,
By providing an electric field relaxation member protruding from the fixed contact or the movable contact, respectively, even when the contact surface of the fixed contact and / or the movable contact is roughened and the tip is formed, the electric field to the respective tip is reduced. Excellent effects are obtained such as concentration can be eased and a decrease in withstand voltage performance can be prevented.

Further, in the switchgear according to the present invention, the fixed contact side has a disk shape having a diameter larger than that of the fixed contact, and the electric field relaxation member sandwiched between the fixed contact and the fixed conductor bar. A conventional switchgear is provided on the movable contact side by forming a cylindrical shape having a diameter larger than that of the movable contact and the movable conductor rod, and by providing an electric field relaxation member disposed around the movable contact and the movable conductor rod. In this case, even if the surface of the fixed contactor and / or the movable contactor is roughened to form a cusp without increasing the number of parts, the concentration of the electric field on each cusp can be reduced. Because of the relaxation, excellent effects such as prevention of a decrease in withstand voltage performance can be obtained.

[Brief description of the drawings]

FIG. 1 is an elevational sectional view showing an open state of a switchgear according to Embodiment 1 of the present invention.

FIG. 2 is an elevational sectional view showing a closed state of the switchgear according to the first embodiment of the present invention.

FIG. 3 is a graph showing the results of a simulation performed on the present invention and a conventional switchgear.

FIG. 4 is an elevational sectional view showing an open state of a switchgear according to a second embodiment of the present invention.

FIG. 5 is an elevational sectional view showing a conventional switchgear.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 vacuum vessel, 2 insulating tube, 3 lower cover plate, 4 upper cover plate, 5 fixed conductor rod, 6 fixed contact, 7 metal bonding material (electric field relaxation member), 8 movable conductor rod, 9 bellows, 10 movable Contact, 11 Electric field relaxation shield, 12
Fixed conductor rod side electric field mitigation shield, 13 bellows cover.

Continued on the front page (72) Inventor Toshifumi Sato 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Seiichi Miyamoto 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric (72) Inventor Takayuki Itoya 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 5G026 CA02 CB02 CC03

Claims (3)

[Claims] 1. A fixed contact, a movable contact in contact with / separating from the fixed contact, a first electric field relaxation member protruding from the fixed contact to the movable contact, and a fixed contact from the movable contact. A switchgear comprising: a second electric field relaxation member protruding toward a slave side. 2. A fixed contact, a movable contact in contact with / separating from the fixed contact, and a first electric field relaxation member disposed around the fixed contact and protruding from the fixed contact to the movable contact side. And a second electric field reduction member disposed around the movable contact and protruding from the movable contact to the fixed contact when the movable contact is at the separated position. 3. A fixed contact in the form of a disk, a movable contact linearly moving in contact with / separating from the fixed contact, and a disk or ring having a diameter larger than that of the fixed contact. A first electric field relaxation member fixed to the contact and having a portion around the fixed contact protruding toward the movable contact from the fixed contact; a cylindrical member having a diameter larger than the movable contact; A second electric field mitigating member that is disposed around and has a portion protruding from the movable contact toward the fixed contact when the movable contact is at the separated position; a fixed electric contact, a movable contact, and a first electric field mitigating member And a container accommodating the second electric field relaxation member.