JPS6388720A - Electrode structure for vacuum breaker - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention was made to improve the short-circuit breaking performance of a vacuum circuit breaker, and relates to the material and structure of electrodes. As a result of equalizing electrode consumption during short-circuit breaking, basic performances such as current carrying performance, welding performance, withstand voltage performance, and electrical life are improved, making it possible to provide a compact vacuum circuit breaker.

[Conventional technology]

FIG. 5 is a plan view showing the electrode structure of a conventional vacuum circuit breaker disclosed in JP-A-55-30174, in which (a) shows, for example, the fixed side electrode, and (2)) shows, for example, the movable side electrode. . When viewed from the opposing surface, the former is a cloth-wrapped electrode, and the latter is an overwhelmingly spiral-shaped electrode. nItl, (Im) are members that can be brought into and out of contact with each other and are called contact portions. +21, (2m) is the arc runner. Spiral groove f41, (4
8) has a contact part ix+, (us) j termination,
The arc runner, (:l, (2m)) is divided into 1,000 sections.Each arc runner has its tip +31,
(38) i It is in contact with the outer periphery of the iron electrode. Note that the number of arc runners is arbitrary. In the figure, the electrode is, for example, C
Alloys containing u-BM (copper-bismuth) and Cu-Cr
It is made of an alloy containing (copper-talom) and is made in one piece.

1. Not shown. /1, but a so-called flat plate structure without a spiral groove is used for the electrode of a vacuum interrupter with a short circuit current of 12.5 kA or less. Even in the flat plate structure, it has a contact portion equivalent to 1111, a taper portion equivalent to an arc runner, and an electrode outer peripheral portion, all of which are integrally made of the same material.

Although not shown, (101) and (10i) in FIG.
A) is connected to an electrode terminal outside the vacuum vessel through the electrode rod.

The vacuum circuit breaker has a bamboo mesh M flow for breaking, closing, and energizing.

Basic performance is required, such as switching of normal current, surge voltage associated with switching, withstand voltage when closing, and lifespan of interruptions. These performances are primarily governed by the electrode material and structure. It is extremely difficult to achieve all of the above performance with a single type of single-pole material (including multi-component alloys), and current-carrying has been put into practical use at the expense of some performance. The electrode material and structure of vacuum circuit breakers for circuit breaker applications are determined with the utmost emphasis on short-circuit current interrupting performance.

Regarding the arc between the lightning poles during current interruption, the diffused arc is dominant in a small current region, and the focused arc is dominant in a large current region. A diffused arc is a mode in which the legs of the arc (cathode spots) can exist in finely dispersed shapes.

Because the current density is small, the magnetic current is cut off and the arc voltage is low, about 50V. On the other hand, a focused arc moat has a large current density because the arc legs are focused, and is easily susceptible to magnetic drive, so materials with focused arc characteristics are used in conventional vacuum circuit breaker electrodes.

Next, use the spiral electrode in Figure 5 to short circuit the AC circuit 7! t
/112.5 to 5 QkA will be clearly explained. At this point, the pair of electrodes begins to open, at the contact point i11.
, is fired from (11). The arc between the M poles is the contact point fx! , (xa) through the arc runner +21, (2 m) to the tip of the arc runner (31, (3 m). At this time, due to the characteristics of the spiral M-pole structure, 1 is A radial magnetic field is formed, and since the direction of this magnetic field is in the direction of the arc ~C!-many angles, this magnetic field is called a transverse magnetic field.The cutting effect of the transverse magnetic field promotes the storage of the arc on the electrode. Ru.

In conventional spiral electrodes, when the arc current drops to several kA or more, the arc mode becomes a focused arc, and multiple legs of the arc (cathode spots) are focused and localized.
The current density increases, the arc voltage also rises to over 100V,
The magnetic drive effect due to the calm field increases. Therefore, the spiral electrode exhibits excellent breaking performance in breaking the rated short-circuit current of the vacuum circuit breaker.

However, when connecting an excessive short-circuit current, the magnetic drive effect mentioned above becomes too effective, and the short-circuit current reaches the current zero point (the tortoise of this arc is at the tip of the arc runner (3) or (3). -) and stagnates there, resulting in excessive heat input to the arc runner tip (3m) or (3) of the opposite electrode ((trough side)) of the arc foot. In the end, the abnormality of the anode part is detected.This is the phenomenon of short-circuit breakage failure.

After this, when observing the state of polar wear, the degree of wear and melting was most significant at the tip of the arc runner (3-) or (3), followed by the tip of the arc runner (21) or (2).
Particularly, the part along the spiral groove (4J), +4) is very bad.
In many cases, the order is l. Arc runner (2s
) or (2), the distance from the spiral groove (4 m) 7 or (4) is that there is not much wear and melting, or there is no wear or melting, or there are even parts that are not worn or melted at all. In other words, from the results of this experimental observation,
With conventional spiral electrodes, the entire area of opposing electrodes cannot be used 100% effectively, and short-circuit breakage often fails.

The above is an example of failure to interrupt an excessive short-circuit current, but even if the rated short-circuit current is tested multiple times, the failure will occur at the end of the life.

The electrode investigation in this case is similar to the electrode observation result after the failure to trace the excessive short-circuit current described above, and again the spiral m (
4g), it is often observed that the parts far from +4+ have slight wear and dissolution.

Generally, the potential gradient at the outer circumference of the electrode is the strongest when the electrode is fully opened, but after the tip of the arc runner abnormally melts, the unevenness becomes severe, so the -@ potential gradient becomes strong and the short-circuit current reaches the current zero point. Because it cannot withstand the dynamic withstand voltage of

In the case of a flat plate electrode, the effective utilization rate of the electrode area is lower than that of a spiral electrode, and short-circuit breaking failures also occur due to abnormal melting of the outer circumference of the electrode.

[Problem that the invention seeks to solve]

Since the electrodes of conventional vacuum circuit breakers are composed only of electrode materials with focused arc characteristics, it is not possible to effectively utilize the entire area of the opposing electrodes. , 1! Miniaturize the bridge (and therefore the vacuum container)
It was difficult to do. The arc voltage is high, so
The wear and tear of the electrodes is also severe, and the surface of the contact area of the electrodes is very rough.
This results in an increase in contact resistance, an increase in welding force, a deterioration in withstand voltage, etc., which poses a problem in extending the trip life of a vacuum circuit breaker.

This invention was made to solve the above-mentioned problems with conventional electrodes, and it prevents abnormal melting of the outer circumference of the electrode, which has the maximum potential gradient, such as the tip of the arc runner, when short-circuit current is interrupted. , to lower the arc voltage to eliminate uneven consumption of the electrodes, and to effectively utilize the entire area of the facing ti (thus, to obtain a vacuum circuit breaker with stable dynamic withstand voltage and long short-circuit/break frequency life). The purpose is to

According to this invention, since the electrode diameter (outer diameter) can be made smaller than before, the vacuum container that houses the xi can also be made smaller, and a second object is to obtain a vacuum circuit breaker that is economically inexpensive.

[Means for solving problems]

The electrode material and electrode structure of the vacuum circuit breaker according to the present invention include a first body made of a conventional material with focused arc characteristics, and a second body made of a material with diffused arc characteristics and whose arc voltage is lower than that of the first body. It is attached. If necessary, a part or all of the contact portion or the outer peripheral portion of the flat or spiral electrode may be constituted by the second structure. In the case of a spiral-shaped electrode, a part of the arc runner can be composed of a second structure, and the second structure can be installed parallel to and apart from the spiral groove that divides the arc runner. Two second structures may be provided near the outer circumferential portion, parallel to the outer circumferential circle, and spaced apart from the tip of the arc runner.

[Effect]

The electrode of the vacuum circuit breaker according to the present invention (in this case, since the second structure made of a material with a diffused arc characteristic and a lower arc voltage than the conventional one is also provided, the first structure made of a material with a higher arc voltage and a focused arc characteristic than the conventional one) The part that had little responsibility for short-circuit arcs has been removed, and the entire surface of the opposing electrodes now contributes to short-circuit breaking.As a result, the average arc voltage at short-circuit breaking is lower than before. 1! Extremely low wear (particularly abnormal melting at the tip of the arc runner of the spiral electrode is eliminated).

It is now possible to provide a vacuum circuit breaker with a long short-circuit breakage life.

〔Example〕

An embodiment of the present invention will be explained below with reference to the drawings. FIG. 1 shows a plan view 9) and a cross-sectional view (b) of one iF pole of a pair of electrodes. In the figure, fil, i2),
+31, (41 is ill in the above-mentioned figure 5, +2
1, +31, and (4), the electric gI first structure is made of a material having focused arc characteristics, and has a contact part, an arc runner part, an arc runner tip, and a spiral groove, respectively. in does not exist in Figure 5,
This is a second electrode structure having diffused arc characteristics. Electrode 2nd
The structure is embedded in the first electrode structure from the center of the arc runner to the electrode periphery, and is installed in a portion of the first electrode structure where arc concentration is less likely to occur.

That is, it is installed away from the portion of the first electrode structure along the spiral groove (4) and the tip of the arc runner (3) where arc concentration is likely to occur.

In the embodiment shown in FIG. 1, the first electrode structure is made of CuB1'I or Ct+Cr material, and the second N electrode structure is made of CuTsu material. Cu cutting material short circuit current 12.5~5QkA
In the range of This is an electrode material that exhibits diffused arc characteristics.

For comparative study 1. A vacuum circuit breaker f- was manufactured using the conventional electric bridge shown in FIG. 5 and the N pole of the present invention shown in FIG.

JE using two types of electrode diameters, 40 and 60 mol.
A short-circuit connection test of C-No. 4 was carried out, a contact resistance before and after 7 and a voltage test of 11 were carried out, and finally, the vacuum container was disassembled and the state of wear of the electrodes was observed.

Next, the function and operation of the embodiment of the invention shown in FIG. 1 will be explained in detail. Table 1 summarizes the results of the comparative R experiment mentioned above. The lightning pressure is lower than that of conventional vacuum circuit breakers, the magnetism and repulsion by the spiral electrodes work effectively, and the surfaces of all electrodes are worn out evenly. It has been verified that the number of times the short circuit current can be interrupted is greater than that of the conventional type, and that the contact resistance and withstand voltage characteristics are stable.

Table 1 shows the case where this invention is applied to both of a pair of electrodes, but when one of the pair of electrodes is applied with this invention, the effect of the invention is slightly reduced, but compared to the conventional method. showed superior performance.

Table 1 Note that in the above embodiment, only one arc runner (2) of the second electrode structure made of a material having diffused arc properties was provided as the second electrode structure made of a material having focused arc properties. As shown in FIG. 2, the second electric bridge structure may be installed from the electrode contact f'A ix+ to the arc runner part (2).

Although the details of the test results of the embodiment shown in FIG. 2 are omitted, the desired effect of the invention was obtained in the rated short-circuit breaking current 29 and the vacuum circuit breaker of A or more (/%). ) is a plan view, (
B) is a sectional view taken along line BB'.

Another embodiment is shown in FIG. 39th letter) is a plan view, and (b) is a sectional view along the t and cr green lines. In this case, a ring-shaped structure (Ili, t3
31 is provided, making manufacturing easier. That is, a ring-shaped structure (Ili) is installed on the entire electric bridge contact part and a part of the arc runner, and a ring-shaped structure (a31) f- is installed on the outer peripheral part of the electrode. The desired effects of the invention were obtained in a large vacuum circuit breaker with an electrode diameter of 5Q+nm or more, which has a strong magnetic drive effect due to the spiral groove.

Furthermore, FIG. 4 shows another embodiment according to the present invention, in which a linear second electrode structure (n) and a ring-shaped second electrode structure are arranged, so that the rated short-circuit breaking i! 20 kA
In the above-mentioned vacuum breaker, the desired effects of the invention were obtained. 4th diagram) is a plan view, (b) is 0) D-1)'
It is a sectional view along the line.

In the embodiment shown in FIGS. 3 and 4, in which a second electrode structure having a diffusion arc characteristic is provided on the outer periphery of one pole, when the short circuit current is interrupted, the arc of the first electrode structure is Abnormal melting at the runner tip (3) was completely eliminated. As a result of (7), there is almost no deterioration of the withstand voltage characteristics after the short-circuit current is cut off. It was found that the effect of 7 is particularly high when the contact opening distance is 12 rnm or more, and it is suitable for a high voltage vacuum circuit breaker of 12 kV or more.

In the embodiments shown in FIGS. 1 to 4, the first electrode structure ζCu
Although the example in which CuTm is used for the second electrode structure using B1 or CuCr is shown, the combination of the first electrode structure and the second electrode structure is as follows.
It is not limited to these.

Furthermore, although an example is not shown, in a flat plate electrode, only the contact portion has a diffusion arc characteristic of 21! For the embodiments in which the pole structure is used and the embodiments in which only the outer periphery of the electrode is used as the second electrode structure, the rated short circuit Ffr1! A remarkable 'invention effect' was observed at a flow rate of 12.5 kA or more.

〔Effect of the invention〕

As described above, according to the present invention, in addition to the conventional first electrode structure having focused arc characteristics, the electrode structure of the vacuum circuit breaker is newly provided with a second electrode structure having diffused arc characteristics. The arc voltage when the short circuit current is broken is reduced, local abnormal melting of the electrode structure does not occur, and the entire surface of the opposing electrodes can be used uniformly to successfully break the short circuit. .

As a result, a long-life vacuum circuit breaker with stable contact resistance and lightning resistance after short-circuit interruption is obtained, and the vacuum vessel can also be made smaller because the electrode diameter can be made smaller than the conventional electrode diameter for the required rated short-circuit current. As a result, it became possible to construct a vacuum circuit breaker at a very low cost over time.

[Brief explanation of the drawing]

FIG. 1 is a plan view and a sectional side view showing an electrode assembly of a vacuum circuit breaker according to an embodiment of the present invention, and FIGS. A plan view and a sectional side view. FIG. 5 shows a plan view of a pair of electrodes of a conventional vacuum circuit breaker viewed from the contact surface. In the figure, fi+ is the contact part, (2) is the arc runner part, (3) is the tip of the arc runner, (4) is the spiral groove, and ``circle'' is the second electrode structure. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (6)

[Claims] (1) In a vacuum circuit breaker equipped with a pair of electrodes that can be relatively connected to and separated from each other inside a vacuum vessel, the first structure is made of a material with focused arc characteristics, and the first structure has a lower arc voltage than the first structure and has diffused arc characteristics. An electrode structure for a vacuum circuit breaker, characterized in that a second structure consisting of: (2) The electrode structure of a vacuum circuit breaker according to claim 1, wherein a part or all of the contact portion of the flat or spiral electrode is constituted by the second structure. (3) The electrode structure of a vacuum circuit breaker according to claim 1, wherein a part of the arc runner portion of the spiral electrode is constituted by a second structure. (4) The electrode structure of a vacuum circuit breaker according to claim 1, wherein a part or all of the outer peripheral portion of the flat or spiral electrode is constituted by the second structure. (5) The electrode structure of a vacuum circuit breaker according to claim 3, characterized in that the second structure is provided substantially parallel to and spaced apart from the spiral grooves that divide the arc runner. (6) The electrode structure of the vacuum circuit breaker according to claim 3, characterized in that the second structure is provided near the outer circumference of the electrode, substantially parallel to the outer circumferential circle, and away from the tip of the arc runner. .