JP5550626B2 - Electrode for vacuum circuit breaker and vacuum circuit breaker - Google Patents

Description

  The present invention relates to a vacuum circuit breaker electrode and a vacuum circuit breaker, and more particularly, to a vacuum circuit breaker electrode and a vacuum circuit breaker suitable for those having a magnetic field generating coil on the back of a contact electrode.

  The vacuum circuit breaker is a device arranged in the power receiving and distributing system, and plays a role of separating a specific portion from the power system as necessary. In particular, in the event of a system failure, they are responsible for cutting off thousands of to tens of thousands of amperes.

  A vacuum circuit breaker applies or interrupts current by connecting and separating a pair of contact electrodes arranged inside a vacuum vessel, and applies a magnetic field perpendicular to the contact electrode end face (hereinafter referred to as a longitudinal magnetic field). By doing so, it is widely known that the current interruption performance is improved.

  As such a vertical magnetic field type vacuum circuit breaker, a structure having a coil conductor for generating a magnetic field on the back of a contact electrode is widely adopted. By constraining the arc generated at the time of current interruption with a magnetic field, local heating of the electrode surface by the arc is suppressed, and the current interruption performance is improved by dispersing the heat load by the arc over the entire electrode surface.

  There exists what was described in patent document 1 as an electrode for vacuum circuit breakers provided with the coil conductor for magnetic field generation. This Patent Document 1 describes an electrode for a vacuum circuit breaker that forms a coil portion by providing an inclined slit in a cylindrical portion of a pot-shaped conductor, and generates a longitudinal magnetic field by passing an electric current therethrough.

  On the other hand, in a vertical magnetic field type vacuum circuit breaker, it is known that an eddy current is generated in an electrode, thereby causing a decrease in magnetic field strength and an increase in a residual magnetic field, resulting in a decrease in breaking performance.

  Therefore, Patent Document 1 employs a structure in which the bottom of the crucible conductor that generates particularly strong eddy currents is moved away from the arc generating part by increasing the crucible depth of the crucible conductor to reduce the influence of the eddy current. ing.

  Moreover, the electrode for vacuum circuit breakers which combined the inclination slit and the vertical slit is described in patent document 2. FIG. In the vacuum circuit breaker electrode described in Patent Document 2, the slit formed on the contact conductor side is a vertical slit, and the vertical slit is followed by the inclined slit and is formed in a staircase shape.

JP 2003-151413 A Japanese Patent Laid-Open No. 2002-334641

  As described in Patent Document 1, the effect of eddy current is reduced by deepening the crucible-shaped conductor forming the vacuum circuit breaker electrode, and a decrease in magnetic field strength and an increase in residual magnetic field can be reduced.

  However, in Patent Document 1, when the crucible conductor is deepened and the inclined slit of the cylindrical portion extends in the axial direction, the center of the coil portion (coil height direction (vertical direction center)) moves away from the arc generating portion. If the turns are the same, the magnetic field strength at the arc generating portion will be reduced.

  In addition, when deepening the pot-shaped conductor, if the number of turns is increased by fixing the tilt angle of the tilt slit in the cylindrical part, the residual magnetic field increases as the magnetic field strength increases, resulting in a decrease in the breaking performance. Is concerned.

  Furthermore, if the crucible conductor is deepened while the shape of the inclined slit (inclination angle, slit height) of the cylindrical portion is fixed, an eddy current is generated in the cylindrical portion located below the inclined slit, so that the residual magnetic field increases. .

  On the other hand, when the vertical slit is formed between the contact conductor and the inclined slit as in the vacuum circuit breaker electrode described in Patent Document 2, it is preferable because the inclined slit moves away from the arc generating portion and the magnetic field strength decreases. It is not a slit arrangement.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a vacuum circuit breaker electrode and a vacuum circuit breaker capable of achieving both an increase in magnetic field strength and a reduction in residual magnetic field.

In order to achieve the above object, an electrode for a vacuum circuit breaker according to the present invention is provided with a slit that is inclined from an end surface on the opening side of the crucible conductor in a cylindrical portion of the crucible conductor, and is continuous with the inclined slit. A slit extending perpendicularly to the opening-side end surface of the shape conductor, and when the distance from the opening-side end surface of the crucible-shaped conductor to the inclined slit end is H and the length L of the vertical slit is 3 It has a relationship of 0.0 ≧ (H + L) / H> 1.5 .

  According to the present invention, there is an effect that it is possible to achieve both an increase in magnetic field strength and a reduction in residual magnetic field.

It is a side view which shows Example 1 of the electrode for vacuum circuit breakers of this invention. It is sectional drawing which shows Example 1 of the electrode for vacuum circuit breakers of this invention. It is AA arrow sectional drawing shown in FIG. It is a perspective view which shows the general longitudinal magnetic field electrode which formed the inclined slit in the cylindrical part of the pot-shaped conductor. It is a perspective view which shows the vertical magnetic field electrode from which a vertical slit does not reach the bottom part of a crucible-shaped conductor. It is a graph which shows the relationship between (H + L) / H, the magnetic field strength, and a residual magnetic field when the height of the inclined slit is H and the vertical slit height L is changed. It is a side view which shows the vacuum circuit breaker of this invention which employ | adopted the electrode for vacuum circuit breakers of Example 1. FIG.

  Hereinafter, the electrode for vacuum circuit breaker and the vacuum circuit breaker of the present invention will be described based on the illustrated embodiment.

  1 to 3 show a first embodiment of a vacuum circuit breaker electrode according to the present invention.

  As shown in the figure, the electrode for a vacuum circuit breaker of this embodiment is generally composed of a contact conductor 1, a crucible conductor 2 and a support 3.

  The contact conductor 1 has a disk shape, and one end face of the contact conductor 1 is in contact with the opening-side end face 2a of the crucible conductor 2 and the support 3. The contact conductor 1 is made of a material having high electrical conductivity and excellent withstand voltage performance, for example, an alloy mainly composed of copper.

  The pot-shaped conductor 2 has a hollow cylindrical shape and includes a cylindrical portion 2b and a bottom portion 2c. The cylindrical portion 2b is inclined at an angle α with respect to the opening-side end surface 2a and extends from the opening-side end surface 2a to a distance H, and from the end of the inclined slit 4 to the opening-side end surface 2a. A vertical slit 5 extending perpendicularly to the distance L is formed. Further, the bottom 2c of the pot-shaped conductor 2 is connected to an external circuit through a current bar (not shown). The crucible conductor 2 is made of a material having high conductivity, for example, oxygen-free copper.

  Assuming that the diameter of the pot-shaped conductor 2 is D, an angle β (see FIG. 3) surrounded by one inclined slit 4 is given by (1).

β = arcsin (H / D / tanα) (1)
The support 3 has a shape in which a disc having a diameter larger than that of the cylinder and a diameter smaller than the inner diameter of the pot-shaped conductor 2 is connected to both end faces of the cylinder. The end face is in contact with the other end face, and the bottom 2c of the pot-shaped conductor 2 is in contact with the other end face. The support 3 is made of a material having a low conductivity and a high elastic coefficient, for example, stainless steel.

  Although the vacuum circuit breaker will be described later, two vacuum circuit breaker electrodes shown in FIG. 1 to FIG. 3 are arranged opposite to each other, and the contact conductors 1 of the vacuum circuit breaker electrodes are connected to and separated from each other. It performs a closing operation and a blocking operation.

  In the vacuum circuit breaker electrode according to the present embodiment, a magnetic field perpendicular to the end face of the contact conductor 1, a so-called longitudinal magnetic field, is generated by the current flowing into the coil portion 6 through the contact conductor 1. The magnetic field strength at this time is proportional to the product of the current flowing through the coil section 6 and the number of turns of the coil, so-called ampere turn.

  In the eddy current generating part such as the bottom 2c of the pot-shaped conductor 2, the influence of the eddy current exerted on the longitudinal magnetic field between the electrodes is small when it is far from the arc. Magnetic field strength increases. Therefore, the ratio of the distance to the eddy current generation portion and the coil height can be used as one of the indexes indicating the current interruption performance.

  As shown in FIG. 4, in a general longitudinal magnetic field electrode in which the inclined slit 4 is formed in the crucible conductor 2, the crucible depth Ht of the crucible conductor 2 is changed from the contact conductor 1 to the eddy current generating portion (the cylindrical portion 2 b of the cylindrical portion 2 b). This represents the distance to the portion where no slit is formed. Therefore, the electrode breaking performance can be expressed by (distance to the eddy current generator) / (coil height) = Ht / H.

  In the general longitudinal magnetic field electrode shown in FIG. 4, Ht / H = 1, but in this embodiment, the vertical slit 5 is provided at the lower end of the inclined slit 4 to obtain the equation (2).

Ht / H> 1 (2)
As shown in FIG. 5, when the vertical slit 5 does not reach the bottom 2c of the pot-shaped conductor 2, that is, when H + L <Ht, the cylinder positioned between the vertical slit 5 and the bottom 2c of the pot-shaped conductor. Eddy current is generated in the part. Therefore, the distance from the contact conductor to the eddy current generation portion is H + L, and Equation (2) is corrected to Equation (3). If there is no vertical slit 5, L = 0.

(H + L) / H> 1 (3)
FIG. 6 shows the relationship between the magnetic field strength and the residual magnetic field and (H + L) / H when the vertical slit length L is changed with respect to the vacuum circuit breaker electrode shown in FIGS. The magnetic field strength and the residual magnetic field are normalized by the maximum value.

  As can be seen from FIG. 6, the magnetic field strength increases as (H + L) / H is increased. On the other hand, when 1 <(H + L) / H <1.5, the effect of reducing the influence of eddy current and the increase in magnetic field strength cancel each other, and the residual magnetic field is the same, but (H + L) / H> 1.5. The residual magnetic field begins to decrease. In addition, since the size of the device increases as the electrode size increases, (H + L) / H is preferably about 3.0 or less. Therefore, in order to achieve both an increase in the magnetic field strength and a reduction in the residual magnetic field, the condition shown in Equation (4) is desirable.

3.0 ≧ (H + L) / H> 1.5 (4)
As described above, by adopting the configuration of the present embodiment, it is possible to provide a longitudinal magnetic field type vacuum circuit breaker electrode that achieves both an increase in magnetic field strength and a reduction in residual magnetic field. In addition, this embodiment can be easily realized only by providing a vertical slit at the lower end of a longitudinal magnetic field electrode having a conventional inclined slit.

  In addition, the electrode for a vacuum circuit breaker in Patent Document 2 described above is a configuration in which the slit on the contact conductor side is a vertical slit, and the vertical slit is followed by an inclined slit, like the vacuum circuit breaker electrode of the present embodiment, The slit on the contact conductor side is an inclined slit, which is different from the configuration in which this inclined slit is followed by a vertical slit. Since the inclined slit has a role of generating a longitudinal magnetic field and is preferably close to the contact electrode, as in Patent Document 2, if there is a vertical slit between the contact conductor and the inclined slit, the inclined slit is removed from the arc generating portion. It is clear that the magnetic field strength decreases as the distance increases, and the effect as in the present embodiment cannot be obtained.

  Next, the vacuum circuit breaker of the present invention employing the vacuum circuit breaker electrode of Example 1 will be described with reference to FIG.

  The vacuum circuit breaker shown in the figure is disposed in a vacuum vessel 14 in which both end portions in the axial direction of a cylindrical insulating tube 7 are sealed with metal end plates 8a and 8b. A pair of fixed and movable electrodes 10a and 10b that are relatively separated from each other, and a fixed and movable rods 9a and 9b that extend out of the vacuum vessel 14 from the back surfaces of the fixed and movable electrodes 10a and 10b. The fixed electrode 10a is fixed to the tip of the fixed rod 9a fixed through the end plate 8a, and the movable rod 9b is attached via the bellows 11 so as to be movable through the end plate 8b, and is movable to the tip of the movable rod 9b. The electrode 10b is fixed. A shield 12 for protecting the insulating cylinder 7 is provided around the fixed electrode 10a and the movable electrode 10b.

  And in the vacuum circuit breaker of this invention, the electrode for vacuum circuit breakers demonstrated in Example 1 is employ | adopted as the above-mentioned fixed electrode 10a and movable electrode 10b.

  Next, the operation for interrupting the current will be described with reference to FIG.

  When the movable electrode 10b is driven in a direction opposite to the fixed electrode 10a by an operating device (not shown), the fixed electrode 10a and the movable electrode 10b are opened, and an arc 13 is generated between both electrodes. A current flows into the contact conductor 1 through the arc 13, and flows to the fixed rod 9 or the movable rod 9 b through the crucible conductor 2.

  With such a configuration, it is possible to provide a vacuum circuit breaker having a good breaking performance.

  DESCRIPTION OF SYMBOLS 1 ... Contact conductor, 2 ... Crucible-shaped conductor, 2a ... Opening side end surface of a crucible-shaped conductor, 2b ... Cylindrical part of a crucible-shaped conductor, 2c ... Bottom part of a crucible-shaped conductor, 3 ... Support body, 4 ... Slant slit, 5 DESCRIPTION OF SYMBOLS ... Vertical slit, 6 ... Coil part, 7 ... Insulating cylinder, 8a, 8b ... End plate, 9a ... Fixed rod, 9b ... Movable rod, 10a ... Fixed electrode, 10b ... Movable electrode, 11 ... Bellows, 12 ... Shield, 13 ... arc, 14 ... vacuum vessel.

Claims (2)

The cylindrical part of the pot-shaped conductor is provided with a slit that is inclined from the opening-side end face of the pot-shaped conductor, and is provided with a slit that is continuous with the inclined slit and extends perpendicular to the opening-side end face of the pot-shaped conductor ;
When the distance from the opening side end surface of the crucible-shaped conductor to the inclined slit end is H, the length L of the vertical slit,
3.0 ≧ (H + L) / H> 1.5
An electrode for a vacuum circuit breaker characterized by having the following relationship: A vacuum vessel in which both end portions in the axial direction of an insulating cylinder formed in a cylindrical shape are sealed with end plates, a pair of relatively fixed and movable electrodes disposed in the vacuum vessel, and the fixed and movable electrodes A fixed and movable rod extending from the back surface of the electrode to the outside of the vacuum container; a bellows for mounting the movable rod so as to be movable with respect to the end plate; and a shield provided around the fixed electrode and the movable electrode. In the provided vacuum circuit breaker,
The vacuum circuit breaker according to claim 1, wherein the fixed electrode and the movable electrode are electrodes for a vacuum circuit breaker according to claim 1 .

Images