JPS61292830A - Vacuum interruptor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a vertical magnetic field application type vacuum interrupter with improved breaking ability.

B0 Summary of the Invention The present invention relates to a vertical magnetic field application type vacuum interrupter that includes a coil on the outside of a metal end plate on the fixed electrode side.

By making the outer diameter of the movable electrode larger than that of the fixed electrode, providing a relaxation shield behind the movable electrode, and setting the gap between the metal end plate and the fixed electrode within a certain range.

This not only prevents polarity effects and electric field concentration, but also prevents arc migration from the fixed electrode to the metal end plate, improving breaking ability.

C1 Conventional technology Vacuum interrupters have a breaking capacity (flow breaking performance,
In order to improve withstand voltage performance) 1, there is a vertical magnetic field application type vacuum interrupter that applies a magnetic field parallel to the arc generated between both electrodes.

There are two types of vertical magnetic field application type vacuum interrupters: those equipped with a coil around the outer periphery of a vacuum container, and those equipped with a coil inside the vacuum container behind at least one electrode. The former has good heat dissipation from the coil, but has the disadvantage that the outer diameter becomes large because the coil is provided around the outer periphery of the vacuum container. -The latter can be made smaller because the coil is housed inside the vacuum container, but the disadvantage is that the heat dissipation is poor because the coil, which is the source of heat generation, is inside the vacuum container, and the durability is poor because the contact between opening and closing acts on the coil. There is.

Therefore, a vertical magnetic field application type vacuum interrupter has been proposed that includes a coil behind the -10,000 electrode and outside the vacuum container (outside the metal end plate). A cross-sectional view of such a vacuum interrupter is shown in FIG. As shown in the figure, the vacuum vessel 4 is released 1R from the insulating tube 1a made of alumina ceramics, etc., the metal tube 1b made of 5us104 L of austenitic stainless steel (hereinafter abbreviated as SUS), and the metal end plates 2, 8, etc. A fixed lead rod 6 and a movable lead rod 7 that can approach and separate from each other are introduced into the vacuum chamber 4.The inner ends of the fixed lead rod 6 and the movable lead rod 7 are coated with Cu-Mo-Cr. (For example, Cu-25Mo-7
8. Fixed electrode made of a composite material made of a powder metallurgy method and having a composition of Cr). A movable electrode 9 is fixed, and a coil [0
is provided. It has been reported in JP-A No. 59-27418 that a composite material composed of Cu-refractory metal-iron group element represented by Cu Mo-Cr and produced by powder metallurgy has excellent breaking ability. Japanese Patent Publication No. 59-119825.
JP-A-59-11%26, JP-A-60-1821. It is known from Japanese Patent Application Laid-Open No. 60-3822. Note that 11 is a shield and has the same potential as the fixed electrode 8. 12 is bellows.

13 Haperose Shield. Furthermore, the fixed electrode 8 and the metal end plate 2 are brought into contact with each other in order to ensure a sufficient longitudinal magnetic field effect between the fixed electrode 8 and the movable electrode 9. This is because it is better to have them as close as possible.

According to the vacuum interrupter, since the coil is provided outside the vacuum container, heat dissipation is improved, and the durability is also good because the straw during opening and closing does not directly act on the coil. Also,
Since the coil is not provided on the outer periphery of the vacuum container, the size can be reduced in the radial direction. It is excellent in terms of size, heat dissipation, durability, etc.

However, in the vicinity of the movable electrode 9, the movable electrode 9 has a coil of
Since the magnetic field lines 14 are far away from each other, the lines of magnetic force 14 are curved outward, causing a polar effect on the breaking performance. That is.

When the fixed electrode 8 is at a negative potential, the breaking performance is inferior to that when the fixed electrode 8 is at a positive potential when cutting off an alternating current. The reason for this is that the magnetic lines of force 14 generated by the coil 10 curve outward as they move from the fixed electrode 8 to the movable electrode 9. When the charged particles are generated from the movable electrode 9 at the time of shutoff, the charged particles are effectively captured by the fixed electrode along the magnetic flux, but when the charged particles are generated from the fixed electrode 8, This is because some (peripheral) charged particles diffuse into the vacuum container along the lines of magnetic force without being captured by the movable electrode 9.

Therefore, when we set the outer diameter of the movable electrode to be larger than the outer diameter of the fixed electrode and investigated the breaking performance, we obtained the following results. When the outer diameter dimensions of the fixed electrode and the movable electrode are the same.

When the breaking performance was t-100 when a positive current was applied to the fixed electrode side, the breaking performance was 80 when a negative current was applied. On the other hand, when the outer diameter of the movable electrode is increased by t-10%, the breaking performance is 110, respectively.
, 90. By increasing the outer diameter of the movable electrode, even though the lines of magnetic force are curved,
This shows that charged particles generated from the fixed electrode are captured by the movable electrode, eliminating the polarity effect.

However, when the outer diameter of the movable electrode is increased.

An irresistible problem arose. That is, as shown in FIG.
As the outer diameter of the movable electrode 9 increases, the electric field concentration at the outer periphery of the movable electrode 9 becomes significant between the movable electrode 9 and the shield 11 having the same potential. In the figure, reference numeral 15 indicates equipotential lines, and it can be seen that the electric field is concentrated on the outer periphery of the movable electrode 9. Therefore, there is a problem in that the withstand voltage performance is lowered and cannot withstand the transient recovery voltage after the interruption M, and as a result, the interruption performance is not the same.

This tendency is reflected in the metal end plate 2 and the metal tube 1b as shown in FIG.
It is better to surround the pair of electrodes 9t with a shield 11 which is a metal member that has the same potential as the fixed electrode 8 through ft than to surround the pair of electrodes with a so-called intermediate shield having an intermediate potential. As the potential difference increases, the electric field strength increases and becomes significant.

The ninth step to solving this problem is to make the outer diameter of the movable electrode without a coil larger than that of the fixed electrode with a gold coil, as shown in Figure 8, and to increase the outer diameter of the movable electrode without a coil. We have devised a vacuum interrupter that includes a light to prevent electric field concentration near the outer periphery, and a relaxation shield that surrounds the inner end of the movable lead rod and extends from the outer periphery of the movable electrode to the outer periphery of the movable lead rod.

In FIG. 8, the outer diameter of the movable electrode 9 is set approximately 10% larger than the outer diameter of the fixed electrode 8 as described above, and the relaxation shield 16 is provided behind the movable electrode 9. . The back side refers to the side to which the movable lead rod 7 is fixed, and refers to the side directly below the movable electrode 9 in FIG. The relaxation shield 16 is provided to surround the inner end of the movable lead rod 7 and to extend gently from the vicinity of the outer peripheral surface of the movable electrode 9 to the outer peripheral surface of the movable lead rod 7. In other words, mitigation shield 1
6 is a hole 16b formed in a trumpet shape and bored in the small diameter part.
The movable lead rod 7 is inserted into and fixed to the movable lead rod 7, and the end of the large diameter portion is bent greatly inward near the outer peripheral surface of the movable electrode 9 to form a curled portion 1.
6& is formed.

Since the relaxation shield 16 is provided to prevent electric field concentration, it is formed into a gently curved surface from the outer circumferential surface of the movable electrode 9 to the outer circumferential surface of the movable lead rod 7. (9) The maximum outer diameter of the relaxation shield 16 is approximately the same as the outer diameter of the movable electrode 9.

This is because when the outer diameter of the movable electrode 9 is increased, the hair arc of the relaxation shield 16 shifts and the breaking performance decreases.
On the other hand, if the outer diameter of the movable electrode 9 is made smaller, the electric field will concentrate near the outer surface of the movable electrode 9 for the same reason as when the relaxation shield 16t is not provided, resulting in a decrease in the breaking performance. In addition to this as a mitigation shield #! The shape shown in Figure 9 (a) # (b) is enough.

Problems that the D9 invention aims to solve However, the breaking ability did not improve as much as expected. So I took it apart and looked into it.

Traces of erosion due to arc transfer to the metal end plate around the fixed electrode were found. Based on this, although we tried to eliminate the polarity effect by making the movable electrode larger, the arc migrated from the fixed electrode to the gold Is end plate, and the vapor generated from the movable electrode was stably captured by the magnetic lines of force. It turns out that there are no limitations.

Based on this fact, we inferred that the gap between the fixed electrode and the metal end plate affected the breaking ability.

The present invention has been made in view of one or more points, and provides a vertical magnetic field application type vacuum interrupter with the highest interrupting ability by setting the gap between the fixed electrode and the metal end plate within a predetermined range. The purpose is to

Ninth way to solve E1 problem The composition of the present invention is to achieve all of these objectives.

A fixed lead rod and a movable lead rod are introduced into a vacuum container formed by fixing metal end plates to both ends of an insulating cylinder so as to penetrate through the metal end plates so as to be able to approach and separate from each other, and a fixed lead rod; A fixed electrode is attached to each Vg end of the movable lead rod.
In a nine-vacuum incrector in which the movable electrode is fixed and a vertical magnetic field generating coil is provided on the outside of the metal end plate on the fixed electrode side, the outer diameter of the movable electrode is formed to be larger than the outer diameter of the fixed electrode, and both electrodes are fixed. A relaxation shield is provided, which is surrounded by a metal member having the same potential as the electrode, surrounds the inner end of the movable lead rod, and extends from the outer peripheral surface of the movable lead rod to the outer peripheral surface of the movable electrode, and the fixed electrode and the metal on the fixed side are provided. It is assumed that the gap with the end plate is set to 2 mm or more and 30% or less of the outer diameter of the fixed electrode.

20 By increasing the outer diameter of the working movable electrode (as compared to the outer diameter of the fixed electrode), the polarity effect is eliminated, and the electric field concentration caused by increasing the size of the movable electrode is alleviated by the relaxation shield, and the The board hair arc has moved and it's 1st year in middle school! ? In order to prevent the capacity from decreasing, the gap between the fixed electrode and the metal end plate is set to 2u or more and 30% or less of the fixed electrode outer diameter, so we can provide a vacuum interrupter with high interrupting capacity. .

G. Embodiments The present invention will be explained in detail below based on embodiments shown in the drawings.

First, the breaking ability of the material formed on the electrode and the metal end plate was tested using a vacuum interrupter having the structure shown in FIG. In the figure, 17 is a pair of insulating cylinders 28 and metal end plates 26,
27 is a vacuum container, 18 is a fixed lead rod, 19 is a movable lead rod, 20 is a fixed electrode, 21 is a movable electrode, 22
23 is a bellows, 23 is an intermediate shield, 24 is a bellows shield, and 25 is a vertical magnetic field generating coil connected in series to the fixed lead rod 18.

FIG. 4 shows the experimental results using the vacuum interrupter shown in FIG. 8, and is a graph showing the relationship between the electrode diameter and the cutoff current when electrodes made of different materials are used. In the figure, (
A) is a composite material made by powder metallurgy with a composition of Cu-25Mo-7Cr, and (B) is 8U8804L.

(/ indicates F and Fe-N1-Co alloys, (-1 indicates the case where Cu t'' is used as the electrode material.The applied voltage in this experiment was 12 KV (r, m, s). The gap between both electrodes is 12 m.
, ←→, ni) are widely used as materials for forming metal end plates.

Figure 5 is a graph showing the relationship between the interelectrode gap and withstand voltage when electrodes made of different materials are used. This shows the case where the electrodes are made of the same material. In addition, the electrode outer diameter is 5
The electrode thickness is 6n at 0 m, and the graph shows the withstand voltage characteristics after a current of 25 KA was cut off 10 times.

From the results shown in Figures 4 and 5, it is clear that Cu by powder metallurgy
-Mo -Cr is 5US-? Cu, etc.] was also found to have good current cutoff performance and withstand voltage performance. In particular, SUS is generally known as a material with good withstand voltage performance, but when an arc is drawn, it is found that the withstand voltage performance is not very good9.

Considering the vacuum interrupter shown in Fig. 8 based on these facts, the electrodes are Cu-Mo-Cr and the metal end plate is 5U.
Because it is S804L, there is a S804L material behind the fixed electrode that is inferior to the material (Cu-Mo-Cr) that makes up this electrode in terms of blocking ability (current blocking performance, withstand voltage performance).
This means that the O8 member is present.

Furthermore, there is a large area of metal end plate directly behind the fixed electrode, which is inferior in breaking ability due to its material. It was found that the characteristics of the metal end plate had a significant negative effect on the current interrupting performance and withstand voltage performance.

Therefore, we investigated how far away the fixed electrode should be from the metal end plate to prevent the arc from transferring from the electrode to the metal end plate.
We investigated how far away the longitudinal magnetic field effect can be reduced.

That is, using the vacuum interrupter shown in FIG. 1, the interruption performance was investigated by varying the gap between the fixed electrode and the metal end plate.

The dimensions of each part of the vacuum interrupter used in the experiment are as shown in Fig. 1: outer diameter of the metal tube a = 110 xx, outer diameter of the coil b - 100 mm, inner diameter of the coil e = 80 m,
Fixed lead rod outer diameter d = 30mm, coil height =
15m, dimension f- between the bottom surface of the coil and the top surface of the metal end plate
2 m, thickness of metal end plate g z 8 t*.

The thickness of the electrode is 5 电, and C≧D (outer diameter of the fixed electrode) so that the magnetic field generated by the coil IOK acts on the entire surface of the fixed electrode 8 and the movable electrode 9. In addition,
29 is an insulator. In such a vacuum interrogator, the relative values of the cut-off current when the gap t between the fixed electrode 8 and the metal end plate 2 is changed are as shown in FIG.
An electrode made of Cu-25Mo-7Cr made by powder metallurgy was used, and a vertical magnetic field was applied using a metal end plate made of SUS 804L. In a certain diagram, (E) is SUS 304 with D=60 (紽)
When there is an L end sheet metal layer, (f) shows the case where it is used as D-50 on the 8U8804 L end plate, and the electrode in each case is Cu-25Mo- made by powder metallurgy.
It is 7Cr. In addition, the outer diameter of the movable electrode is
(a+).

In the figure, * p, a Pt indicates the range where the arc moves from the electrode 8 to the metal end plate 2 and the shearing performance is low due to the small value of t, and 5-Qx-Qt is the current Indicates the range in which shearing performance ft100'16 can be demonstrated.
) + Rt * Rt indicates a range in which the longitudinal magnetic field effect decreases due to a large value of t, and the current interrupting performance becomes low. As can be seen from the figure, when the value of t is small, the hair arc of the metal end plate is likely to migrate, so the dependence on the material that makes up the entire metal end plate is large, while when the value of t is large, the hair arc of the metal end plate is easy to migrate. Since there is no transition, there is no dependence on the material, but on the other hand, the strength of the magnetic field dominates. Furthermore, it can be seen that as the outer diameter of the fixed electrode increases, the magnetic field area expands and the value of 5t may be slightly increased. Current breaking performance'
The range of Ql-Ql that can exhibit 1loOchi is shown in the table below.

As can be seen from Figure 2 and the table above, the range of t depends on the outer diameter of the fixed electrode, partly because the longitudinal magnetic field is applied by a single biased coil. Therefore, in other words, in the case of sD-50m, i=+a15n can be expressed as t-α3D, and in the case of ft-D=60 vm,
t20g can be expressed as α8D in t. Therefore, if 5US804L is used for the metal end plate, 2 絽≦
If t≦α3D, then 1! A vacuum interrupter with high flow interrupting performance, that is, high interrupting ability, can be obtained.

In this example, the electrode material was a composite material composed of Cu-refractory metal monoiron group element and produced by powder metallurgy.
That is, using Cu-Mo-Cr f, the following case is shown.
W- as a refractory metal? A similar effect can be obtained by using Nbe as well as Co, F., and Ni@ as iron group elements. tfe*cue The composition range of refractory metals and iron group elements is determined to satisfy the boar conditions required for electrode materials, Cu is 20 to 80% by weight, refractory metals are 5 to 45% by weight, iron Group elements are 5-45'! It is best to use it in small quantities.

In addition, the metal end plates are generally made of SUS 804 L, but other austenitic SUS materials or Cu
, F@, F.--Ni--Co, similar effects can be obtained.

H1 Effects of the Invention As explained above, according to the present invention, the gap between the fixed electrode and the metal end plate is set to be greater than or equal to f 2 wx and less than 30% of the outer diameter of the fixed electrode, and the outer diameter of the movable electrode is The polarity effect and electric field concentration are prevented by making the diameter larger than the outer diameter of the fixed electrode and by providing a relaxation shield behind the movable electrode.

The arc is transferred from the fixed electrode to the metal end plate, and the longitudinal magnetic field effect due to the coil is reduced, and the breaking performance, withstand voltage performance, and breaking ability are improved.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the vacuum interrupter according to the present invention.
Figure 2 is a graph showing the relative magnitude of the cutoff current when the gap between the metal end plate and the fixed electrode is changed, and Figure 3 is a graph showing the relative magnitude of the cutoff current when the gap between the metal end plate and the fixed electrode is changed. A cross-sectional view of an interrupter. Fig. 4 is a graph showing the relationship between the electrode diameter and cutoff current in the vacuum interrupter shown in Fig. 3, Fig. 5 is a graph showing the relationship between the interelectrode gap and withstand voltage in the vacuum interrupter shown in Fig. 8, and Fig. 6 is a cross-sectional view of a vertical magnetic field application type vacuum interrupter with a fixed electrode in contact with a metal end plate, ii!
Figure 7 is an explanatory diagram showing the distribution of equipotential lines when the outer diameter of the movable electrode is increased in the vacuum ink crack of Figure 6, and Figure 8 is an explanatory diagram showing the distribution of the outer diameter of the movable electrode in the vacuum interrupter of Figure 6. Explanatory diagram showing the distribution of equipotential lines in the case of increasing the size and providing a relaxation shield, Figure 9 (') t
(bl is a sectional view showing other relaxation shields. 1 &... Insulating tube, 1b... Metal tube, 2, 8... Metal end plate, 4... Vacuum container, θ... Fixed Lead dedication, 7
...Movable lead salary, 8...Fixed electrode, 9...Movable electrode, 10...Coil, 11...Shield, C.
... Inner diameter dimension of the coil, t... Gap between the fixed electrode and metal end plate, D... Outer diameter dimension of the fixed electrode. Fig. 3 nose note I] Tarabuku (lr) '7-faced'] shiblindness 411 rep

Claims (1)

[Claims] A fixed lead rod and a movable lead rod are introduced into a vacuum container formed by fixing metal end plates to both ends of an insulating cylinder so as to penetrate through the metal end plates so as to be able to approach and separate from each other, and a fixed lead rod; In a vacuum interrupter in which a fixed electrode and a movable electrode are fixed to the inner end of a movable lead rod, respectively, and a vertical magnetic field generating coil is provided on the outside of the metal end plate on the fixed electrode side, the outer diameter of the movable electrode is set to the outer diameter of the fixed electrode. A relaxation shield is formed larger than the diameter dimension and surrounds both electrodes with a metal member having the same potential as the fixed electrode, and extends from the outer circumferential surface of the movable lead rod to the outer circumferential surface of the movable electrode. A vacuum interrupter characterized in that a gap with an end plate is set to 2 mm or more and 30% or less of the outer diameter of the fixed electrode.