JP5240177B2 - Disconnector - Google Patents

Description

  The present invention relates to a disconnector having a function of cutting off a small current.

  In the conventional disconnector, the movable electrode is constituted by a three-part rod-shaped continuous body of a metal part, a resistor and another metal part in the axial direction, and a contact for introducing a current into the movable electrode is made of another metal. When a re-ignition occurs at the time of opening, the arc is ignited at the tip of the movable electrode so that the current flows through the resistor. The generated surge can be suppressed. In addition, in a state where the movable electrode is put in, the resistor is short-circuited by electrically connecting the metal portion and another metal portion with a short-circuit electrode so that the resistor is not inserted into the circuit (for example, Patent Documents). 1).

JP-A-2-165526

  In the conventional disconnector, the movable electrode is composed of a rod-like continuous body of three parts, a metal part, a resistor, and another metal part in the axial direction, and is in sliding contact with different parts of the outer peripheral part of the continuous body. A contact and a short-circuit electrode were provided. Therefore, the length of the movable electrode is increased, and the size of the component constituting the short-circuit electrode and the space for storing the component are increased. In addition, in the opening / closing pole operation, since it is necessary to slide the short-circuit electrode with the movable electrode in addition to the contact, the frictional resistance accompanying sliding increases, and the opening / closing operation force must be increased. That is, in the conventional disconnector, there is a problem that the device is increased in size in order to suppress the surge by the resistor.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a small disconnector that can suppress a surge during switching pole operation.

  The disconnector according to the present invention is a disconnector that opens and closes a power circuit by moving a movable electrode into which a current is introduced by sliding contact with a fixed contact to and from a fixed electrode. The electrode includes a rod-shaped movable conductor having a central axis in the direction of the opening / closing pole operation and contacting and separating from the fixed electrode at the tip, and a cylindrical resistor covering a part of the outer peripheral surface of the side of the movable conductor have. The cylindrical resistor is formed on the fixed electrode from a position where at least the movable electrode is insulated from the voltage applied between the movable electrode and the fixed electrode by the switching pole operation. While moving to the position to start contact, the contact is inserted between the sliding contact portion of the contact and the movable conductor. Further, the resistor is disposed so as not to be inserted between the sliding contact portion and the movable conductor in a closed state where the movable electrode is further moved to the fixed electrode side from a position where the movable electrode starts the contact. Is.

  According to the present invention, it is possible to obtain a small disconnector that can suppress a surge during switching pole operation.

It is a fragmentary sectional view which shows the structure inside the disconnector by Embodiment 1 of this invention. It is sectional drawing of the principal part in the open circuit state of the arc-extinguishing chamber of the disconnector by Embodiment 1 of this invention. It is sectional drawing of the principal part in the closed state of the arc-extinguishing chamber of the disconnector by Embodiment 1 of this invention. It is sectional drawing of the movable electrode of the arc-extinguishing chamber of the disconnector by Embodiment 1 of this invention. It is sectional drawing of the principal part which shows the state of the arc extinguishing chamber at the time of an arc igniting between the movable electrode and stationary arc electrode in the closing operation by Embodiment 1 of this invention. It is sectional drawing of the principal part which shows the state of the arc extinguishing chamber at the time of the movable electrode in the closing operation by Embodiment 1 of this invention contacting a fixed arc electrode. It is sectional drawing of the principal part which shows the state of the arc-extinguishing chamber just before the movable electrode in closing operation by Embodiment 1 of this invention contacts a fixed main electrode. It is sectional drawing which shows the modification of the movable electrode by Embodiment 1 of this invention. It is sectional drawing of the movable electrode by Embodiment 2 of this invention. It is sectional drawing of the movable electrode by Embodiment 3 of this invention.

Embodiment 1 FIG.
FIG. 1 is a view showing an internal structure by taking a cross section of a metal casing 1 and the like of a disconnector according to Embodiment 1 of the present invention. Inside the metal housing 1, a movable electrode device 2 and a fixed electrode device 3 are fixed to an insulating spacer 6 via a movable terminal 4 and a fixed terminal 5, respectively. The operating force of the operating device 7 fixed outside the metal housing 1 is transmitted to the movable electrode device 2 by the operating rod 8. The inside of the metal housing 1 is filled with an insulating gas such as air, SF6 gas, and nitrogen. FIG. 2 is a cross-sectional view showing the main part of the arc extinguishing chamber surrounded by the one-dot chain line in FIG. 1, and is in an open circuit state. FIG. 3 shows the main part in the closed state.

The movable electrode 9 has a rod shape having a central axis in the opening / closing pole operation direction, and the rotation operation of the operation rod 8 by the operation device 7 is converted into a linear motion by a rack and opinion or the like, thereby closing operation. 2 is driven to the right in FIG. 2, and to the left in FIG. 3 during the opening operation. In the closed state, the tip of the movable electrode 9 is in contact with both the fixed arc electrode 11 and the fixed main electrode 12 that constitute the fixed electrode 9. The fixed-side shield 13 is disposed so as to surround the fixed arc electrode 11 and the fixed main electrode 12, and has a role of relaxing electric field concentration on the fixed electrode 9 side. The electric current is introduced into the movable electrode 9 from the contact 14 that is slidably in contact with the side of the rod-shaped movable electrode 9. This contactor 14 is fixed to a disconnector body structure not shown in the drawing. The movable shield 15 is disposed so as to surround the movable electrode 9 and the contact 14 and has a role of relaxing electric field concentration on the movable electrode 9 side.

FIG. 4 shows a cross-sectional view of the movable electrode 9. The movable electrode 9 has a rod-shaped movable conductor 16 having a central axis in the switching pole operating direction, and a hollow cylindrical resistor 17 fixed so as to cover a part of the outer peripheral surface of the side of the movable conductor 16. Furthermore, a metal plate 18 is attached to the outer peripheral surface of the resistor 17, that is, the surface on the contact 14 side. As the resistor 17, for example, a metal alloy-based resistor such as a copper-nickel alloy, a copper-manganese alloy, or a nickel-chromium alloy, or a sintered resistor of ceramics and metal is used. The end surface of the metal plate 18 opposite to the fixed electrode 10 is in contact with the insulator 19, and the end surface of the metal plate 18 on the fixed electrode 10 side is in contact with the resistor 17, so that the movable conductor 16 and the metal plate 18 are not in direct contact. It is configured. The sliding surface of the metal plate 18 with the contact 14 is set to have a material and surface roughness so that the drag force when sliding is smaller than that of the resistor 17. In addition, the insulator 19 is also set to have a material and surface roughness so that the drag force when sliding is smaller than that of the resistor 17, and the length of the insulator 19 in the central axis direction is slid. The moving contact portion 14a (contact surface) is shorter than the length in the central axis direction.

As shown in FIG. 3, the position of the resistor 17 in the direction of the central axis is arranged so that the contact 14 does not contact the resistor 17 in a closed state. The contact 14 is directly connected to the movable conductor 16. Contact with. Therefore, in the closed state, as indicated by an arrow in FIG. 3, the energized current avoids the resistor 17 having a high resistance value and moves from the contactor 14 to the fixed main electrode 12 in the vicinity of the central axis of the movable conductor 16. It flows. Further, during the operation of the switching pole, the metal plate 18 directly contacts and slides with the contact 14, so that current flows from the contact 14 to the resistor 17 through the metal plate 18, and further, the resistor It flows from 17 to the movable conductor 16.

Next, the closing operation of the disconnector of the present invention will be described. From the state shown in FIG. 2, which is an open circuit state, the movable electrode 9 starts to move rightward in FIG. 2 by the operating device 7, and the contact 14 and the resistor 17 come into contact with each other. Since the distance between the two electrodes of the fixed arc electrode 11 and the movable electrode 9 becomes shorter as the closing operation proceeds, the insulation between the electrodes cannot withstand the voltage applied between the two electrodes. As shown, an arc is generated between the tip of the movable electrode 9 and the fixed arc electrode 11 of the fixed electrode 9. Furthermore, due to the arc firing, a surge during the closing operation (hereinafter referred to as a closing surge) occurs in the circuit connecting the disconnector. The surge during the switching pole operation of the disconnector is continuously generated over several cycles of the commercial frequency. An input surge becomes an overvoltage in a power circuit, and an extremely large overvoltage may occur in a disconnector that does not have surge suppression means. This overvoltage may cause insulation problems in power equipment ("Electrical Cooperative Research" Vol.57, No.3 ", edited by Electric Cooperative Research Society, published in 2002, Chapter 2, Section 2-2). In the disconnector of the present invention, as shown in FIG. 5, the resistance in which the metal plate 18 is fixed between the sliding contact portion 14 a of the contact 14 and the movable conductor 16 at the position of the movable electrode 9 where the arc is generated. Since the body 17 is inserted, a surge current flows through the resistor 17 and is attenuated, thereby suppressing overvoltage.

When the closing operation proceeds and the tip of the movable conductor 16 comes into contact with the fixed arc electrode 11 as shown in FIG. 6, no arc is generated and no surge is generated. After the contact of the distal end portion of the movable conductor 16, the closing operation further proceeds, and when the state shown in FIG. As described above, since the length of the insulator 19 in the direction of the central axis is shorter than the length of the contact surface of the contactor 14 in the direction of the central axis, the contactor 14 is connected to the metal plate 18 and the movable conductor 16. Since it can contact simultaneously, it does not become an electrically insulated state.

When the closing operation further proceeds and the movable electrode 9 comes into contact with the fixed main electrode 12, or immediately before the movable electrode 9 comes into contact with the fixed main electrode 12, the resistor 17 and the contact 14 are separated from each other. Then, the contact 14 comes into direct contact with the movable conductor 16 to reach a closed state as shown in FIG.

Thus, in the disconnector shown in this embodiment, the resistor 17 can be inserted into the circuit at the position of the movable electrode 9 where the arc is generated during the closing operation, so that the surge surge can be suppressed. . In the above description, the case of the closing operation is taken up. However, the voltage applied during the opening operation is an alternating voltage, or a voltage that fluctuates is applied, such as when a small current is cut off. Thus, when no arc is generated at the initial stage of opening and the arc is generated in the middle of the opening, or when the arc is regenerated after being extinguished in the middle of the opening, the surge can be similarly suppressed.

In addition, since the resistor 17 has a cylindrical shape that covers the outer peripheral surface of the movable electrode 9, the movable electrode 9 is a three-piece rod-shaped continuous body of the metal portion, the resistor, and another metal portion in the direction of the central axis. Therefore, the dimension of the movable electrode 9 in the direction of the central axis associated with the provision of the resistor 17 is not increased.

Further, since it is not necessary to separately provide a short-circuit electrode for short-circuiting the resistor 17 in the closed circuit state, surge suppression by the resistor 17 can be performed with a small and simple structure. Furthermore, since it is not necessary to provide sliding contact between the short-circuit electrode and the movable electrode 9, it is not necessary to reinforce the opening / closing operation force of the operating device 7 corresponding to the increase in frictional resistance accompanying the sliding contact.

  From the above, there is an effect of obtaining a small disconnector that can suppress a surge during the switching pole operation.

Further, the metal plate 18 is fixed to the surface of the resistor 17 on the side of the contact 14 so that the contact 14 and the metal plate 18 are in sliding contact during the switching pole operation. The sliding frictional force (drag) can be reduced, the driving force of the operating device 7 that performs the opening / closing pole operation can be set small, and the operating device 7 can be miniaturized.

Furthermore, the sliding friction can be similarly reduced by providing the insulator 19. At the position of the movable electrode 9 where the contact 14 and the insulator 19 slide, the tip of the movable conductor 16 slides simultaneously with the fixed arc electrode 11 and the fixed main electrode 12, and in particular, a large switching pole operating force is exerted. I need. Therefore, the insulator 19 can prevent the direct contact between the metal plate 18 and the movable conductor 16, can set the maximum driving force required for the operating device 7, and can reduce the size of the operating device 7.

Further, in the closed state, it is not necessary to short-circuit the resistor 17 with a short-circuit electrode as in the case of a conventional disconnector, so that a current is passed from the contactor 14 to the fixed electrode 9 via the movable conductor 16 at the minimum contact point. It can be energized, and the heat dissipation characteristics are not deteriorated due to the installation of the resistor 17 for surge suppression.

In this embodiment, as shown in FIG. 2, the contactor 14 is configured to be separated from the resistor 17 and to contact the movable conductor 16 in the open circuit state. The length of the resistor 17 may be increased toward the fixed electrode 10 so that the body 17 contacts.

In this embodiment, the metal plate 18 and the insulator 19 are used in order to reduce the drag due to the sliding of the contact 14. However, for example, a metal alloy resistor 17 is used, and the outer peripheral surface of the resistor is used. When sufficient finishing treatment is performed on the surface on the side to reduce the drag caused by sliding with the contact 14, the metal plate 18 and the insulator 19 may not be provided as shown in FIG. 8.

Embodiment 2. FIG.
FIG. 9 is a sectional view of the movable electrode 9 according to the second embodiment. In this embodiment, a slit hole 20 extending in the direction of the central axis of the movable electrode 9 is provided in the cylindrical portion of the resistor 17 and the metal plate 18 shown in the first embodiment. Since other configurations are the same as those in the first embodiment, the following description will be made on differences from the first embodiment.

In the closed state, the energized current flows concentratedly on the movable conductor 16 through the resistor 17. Therefore, in a disconnector with a large energizing current compared to the cross-sectional area of the thin portion covered with the resistor 17 of the movable conductor 16, the temperature of the thin portion may increase. Furthermore, since the resistor 17 has a lower thermal conductivity than the conductor, there is a possibility that the heat generated in the thin portion cannot be sufficiently radiated from the surface of the resistor 17. Therefore, in this embodiment, the slit hole 20 is provided in the resistor 17 and the metal plate 18 so that the surface of the movable conductor 16 is in direct contact with the surrounding gas, thereby radiating heat to the surrounding gas. Promoting. By promoting this heat dissipation, a large energizing capacity can be realized by the thinner movable electrode 9, so that the radial dimension of the disconnector can be reduced.

In the disconnector using the movable electrode 9 as described above, the same effects as those of the first embodiment can be obtained.

Embodiment 3 FIG.
FIG. 10 is a cross-sectional view of the movable electrode 9 according to the third embodiment. In this embodiment, a heat radiating hole 21 is provided along the central axis of the movable conductor 16 shown in the first embodiment, and the portion of the heat radiating hole 21 is filled with ambient gas. Since other configurations are the same as those in the first embodiment, the following description will be made on differences from the first embodiment.

In the closed state, the energized current flows concentratedly on the movable conductor 16 through the resistor 17. Therefore, in a disconnector with a large energizing current compared to the cross-sectional area of the thin portion covered with the resistor 17 of the movable conductor 16, the temperature of the thin portion may increase. Furthermore, since the resistor 17 has a lower thermal conductivity than the conductor, there is a possibility that the heat generated in the thin portion cannot be sufficiently radiated from the surface of the resistor 17. Therefore, in this embodiment, by radiating heat from the surface of the heat radiating hole 21 to the surrounding gas, it is possible to suppress a temperature rise in a thin portion covered with the resistor 17 of the movable conductor 16.

In the disconnector using the movable electrode 9 as described above, the same effects as those of the first embodiment can be obtained.

Further, even if the heat dissipation hole 21 is provided in the movable electrode 9 shown in the second embodiment, it is possible to suppress an increase in temperature of a thin portion covered with the resistor 17 of the movable conductor 16 as described above.

Embodiment 4 FIG.
In the fourth embodiment, the magnitude of the resistance value of the resistor 17 shown in the first embodiment is changed from the characteristic impedance Z ₀ (also called surge impedance) and the circumference of the power circuit to which the disconnector of the present invention is applied. The value is greater than or equal to the product of the rate π. Since other configurations are the same as those in the first embodiment, the following description will be made on differences from the first embodiment.

Examples of the power circuit include, for example, a coaxial bus part such as a gas insulated switchgear or a circuit in which a coaxial cable is connected. Further, when equivalent characteristic impedance is required in other circuits, the same can be handled.

  Generally, 1 / f is the lower limit of the surge decay time constant τ with respect to the surge frequency f, and if the decay time constant is less than 1 / f, it can be considered that sufficient attenuation is performed ( “Electrical Energy Engineering” Corona, first edition, 5th edition, issued December 10, 2004, paragraph 145). On the other hand, since it can be considered that the circuit in which the surge is generated can be approximated to an LRC series resonance circuit, the decay time constant τ derived therefrom is obtained by using the inductance L and the resistance value R.

と表される。
また、サージの周波数ｆは、上記インダクタンスＬとキャパシタンスＣを用いて

It is expressed.
The frequency f of the surge is calculated using the inductance L and capacitance C.

で表される。
ここで、πは円周率である。τ≦１/ｆであるには

It is represented by
Here, π is the circumference ratio. To satisfy τ ≦ 1 / f

を満たせばよいので、Ｒが満たす式は

Therefore, the equation that R satisfies is

であればよい。
ここで、特性インピーダンスＺ₀は

If it is.
Here, the characteristic impedance Z ₀ is

と表されるので、抵抗体１７の値は、

Therefore, the value of the resistor 17 is

とすればよい。

And it is sufficient.

By determining the resistance value of the resistor 17 as described above, it is possible to obtain an effect of attenuating the surge to a sufficient degree that does not harm the power equipment.

Even if the resistance value of the resistor 17 shown in the second or third embodiment is set to a value equal to or greater than the product of the characteristic impedance Z ₀ and the circular ratio π of the power circuit, the surge is not harmful to the power equipment. It can be attenuated to a certain extent.

DESCRIPTION OF SYMBOLS 1 Metal housing, 2 Movable side electrode apparatus, 3 Fixed side electrode apparatus, 4 Movable side terminal, 5 Fixed side terminal, 6 Insulating spacer, 7 Operation apparatus, 8 Operation rod, 9 Movable electrode, 10 Fixed electrode, 11 Fixed arc Electrode, 12 Fixed main electrode, 13 Fixed shield, 14 Contact, 14a Sliding contact part, 15 Movable shield, 16 Movable conductor, 17 Resistor, 18 Metal plate, 19 Insulator, 20 Slit hole, 21 Heat dissipation hole .

Claims (5)

In a disconnector that opens and closes a power circuit by moving a movable electrode into which a current is introduced by sliding contact with a fixed contact to and from a fixed electrode,
The movable electrode is
A rod-shaped movable conductor having a central axis in the direction of the switching pole operation and contacting and separating from the fixed electrode at the tip, and a cylindrical resistor covering a part of the outer peripheral surface of the side of the movable conductor And
The cylindrical resistor is
By the opening / closing pole operation, at least the movable electrode moves from a position where insulation is maintained with respect to a voltage applied between the movable electrode and the fixed electrode to a position where contact with the fixed electrode is started. Is inserted between the sliding contact portion of the contact and the movable conductor,
In addition, in the closed state in which the movable electrode is further moved to the fixed electrode side from the position where the contact is started, the disconnection is arranged so as not to be inserted between the sliding contact portion and the movable conductor. vessel. A contact surface of the cylindrical resistor has a metal plate electrically connected to the cylindrical resistor and not in direct contact with the movable conductor, and the contact is in sliding contact with the metal plate. The disconnector according to claim 1. The cylindrical resistor has a slit hole extending in the direction of the central axis of the movable conductor, and ambient gas flowing into the slit hole is in direct contact with the movable conductor. Disconnector. The disconnector according to claim 1 or 2, wherein the movable electrode has a heat radiating hole provided along the central axis. The disconnector according to any one of claims 1 to 4, wherein the resistance value of the cylindrical resistor is equal to or greater than the product of the characteristic impedance of the power circuit and the circumference ratio.

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