Current conversion method for vacuum interrupters

Abstract

To provide a method for electrochemical treatment of electrodes that can be carried out simply and effectively. [Solution] The current chemical treatment method of the present invention performs current chemical treatment on each electrode by opening the fixed electrode (22) and movable electrode (23) of a vacuum interrupter (11) connected to a chemical treatment power supply (12) to generate an arc (A). The method includes an arc generation step S0 and S1 in which a DC voltage is applied from the chemical treatment power supply to the vacuum interrupter and an arc is generated by opening the electrodes to separate them, and an arc generation step in which the generation of the arc in the arc generation step is maintained while the distance between the electrodes (D) is increased between the electrodes. n ) and current (I n The adjustment steps S2 to S4 are performed, which involve changing the conditions of ) to multiple other conditions.

Description

[Technical Field]

[0001] This invention relates to a method for generating current in a vacuum interrupter. [Background technology]

[0002] Patent Document 1 discloses a vacuum interrupter in which a pair of electrodes, arranged opposite each other so as to be able to move toward and away from each other within a vacuum vessel, are conditioned by opening and closing them with a low DC current. Patent Document 2 discloses a vacuum interrupter in which an AC voltage is applied between closed electrodes, and the electrodes are opened while the AC voltage is still applied between the electrodes, and the electrode surfaces are chemically formed by an arc generated between the electrodes. In the chemical formation described in Patent Document 2, a magnetic field in the same direction as the arc is applied by a coil, and the electrodes are opened at a speed faster than the rated opening speed. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 1-281631 [Patent Document 2] Special Publication No. 8-28157 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In Patent Document 1, the current is small because the arc is repeatedly interrupted, which may result in insufficient conditioning of the electrode surface. This leads to the problem that the number of times the electrode is opened and closed must be increased in order to increase the energy supplied to the electrode in order to adequately condition it. In Patent Document 2, the electrode is opened at high speed, which makes it difficult to control the position and timing of the arc generation necessary for chemical formation of the electrode surface, and consequently leads to insufficient chemical formation of the electrode.

[0005] This invention has been made in view of the above circumstances, and aims to provide a method for electrochemically transforming a vacuum interruptor, which can perform the electrochemical transformation treatment of electrodes simply and effectively.

Means for Solving the Problem

[0006] A method for current formation of a vacuum interrupter according to an aspect of the present invention is a method for current formation of a vacuum interrupter in which a pair of electrodes of the vacuum interrupter connected to a DC power source are opened to generate an arc to subject the electrodes to current formation treatment, the method comprising: an arc generation step of applying a DC voltage from the DC power source to the vacuum interrupter and generating the arc by an opening operation of separating one of the electrodes from the other electrode; and an adjustment step of changing an electrode distance and a conduction current between one of the electrodes and the other electrode under a plurality of conditions while maintaining the generation of the arc in the arc generation step.

Effect of the Invention

[0007] According to the present invention, since the electrode distance and the conduction current are changed under a plurality of conditions while maintaining the generation of the arc, it is possible to reduce the number of opening and closing operations of the electrodes and simplify the current formation treatment. Moreover, by changing the electrode distance and the conduction current, it is possible to adjust so that the entire surface of the electrode is altered to a desired molten state, and the current formation treatment can be effectively carried out.

Brief Description of the Drawings

[0008] [[ID=第十九]] [Figure 1] It is a configuration diagram of a current formation processing circuit of a vacuum interrupter in an embodiment. [Figure 2] It is a flowchart in the current formation method of an embodiment. [Figure 3] It is a configuration diagram similar to FIG. 1 for explaining an example of an inversion step. [Figure 4] It is a configuration diagram similar to FIG. 1 for explaining another example of an inversion step.

Mode for Carrying Out the Invention

[0009] Hereinafter, a current forming process method for a vacuum interrupter according to an embodiment will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiments, and can be appropriately modified and implemented within the scope without changing its gist. The orientation of each component in the following embodiments is merely an example, and can be changed to any orientation.

[0010] FIG. 1 is a configuration diagram of a current forming process circuit for a vacuum interrupter in an embodiment. As shown in FIG. 1, the circuit for implementing the current forming method of the present embodiment includes a vacuum interrupter 11, a forming power source 12 serving as a DC power source, an ammeter 13, and a voltmeter 14.

[0011] The vacuum interrupter 11 has a vacuum vessel 21 whose interior is maintained in a vacuum, and a pair of electrodes 22, 23 accommodated in the vacuum vessel 21. Of the pair of electrodes 22, 23, one is a fixed electrode 22 and the other is a movable electrode 23. In FIG. 1, the movable electrode 23 is configured to be able to open and close in the vertical direction via an opening and closing mechanism not shown, and closes when the movable electrode 23 contacts the fixed electrode 22 due to this movement, and opens when they are separated. The separation distance between the fixed electrode 22 and the movable electrode 23 in the open state is the electrode distance D n (n is an integer of 0 or more, the same applies hereinafter).

[0012] The fixed electrode 22 is grounded via a fixed-side current-carrying shaft 25 and a ground cable 26, and the movable electrode 23 is connected to a wiring cable 28 via a movable-side current-carrying shaft 27.

[0013] The forming power source 12 is provided with a DC voltage source 31 and a variable resistor 32 connected in a series circuit, and the output voltage E n and the output current can be made variable. The cathode side of the DC voltage source 31 of the forming power source 12 is grounded, and it is also connected to the movable electrode 23 of the vacuum interrupter 11 via the wiring cable 28. In the state shown in FIG. 1, the fixed electrode 22 of the vacuum interrupter 11 connected to the forming power source 12 is the cathode, and the movable electrode 23 is the anode.

[0014] The ammeter 13 is installed on the wiring cable 28 and measures the current I supplied to the vacuum interrupter 11 by the chemical power supply 12. n Measure the current I. n This value is set to be the same as the output current of the chemical power supply 12.

[0015] The voltmeter 14 is provided on a wiring cable 34 that is connected to and grounded between the ammeter 13 and the vacuum interrupter 11 in the wiring cable 28. The voltmeter 14 measures the inter-electrode voltage V between the fixed electrode 22 and the movable electrode 23. n Measure.

[0016] In this embodiment, a switchgear mechanism (not shown) for driving the movable electrode 23, a chemical power supply 12, and a control unit (not shown) connected to the ammeter 13 and voltmeter 14 can be provided. The control unit consists of a processor that performs various processes and a memory that stores programs. Based on the programs stored in the control unit's memory and the outputs of the ammeter 13 and voltmeter 14, the switchgear mechanism and the chemical power supply 12 may be controlled to implement the current chemical method described later.

[0017] Next, the current-forming method for each electrode 22 and 23 using the circuit in Figure 1 will be explained with reference to Figure 2. Figure 2 is a flowchart of the current-forming method of this embodiment. The current-forming method of this embodiment is carried out in the order of steps S0, S1, S2, S3, S4, and S5, as described below, with steps S0 to S4 corresponding to S0 to S4 shown in Figure 2. Note that the main operator of the power supply 12 for forming the chemicals and the movable electrode 23 in each step described later may be the control unit described above, or it may be done by an operator.

[0018] In step S0 in the initial state, each electrode 22, 23 of the vacuum interrupter 11 connected to the forming power supply 12 is set to the closed electrode state. Then, immediately before the opening operation of each electrode 22, 23, a DC voltage is applied to the vacuum interrupter 11 with the output voltage E0 from the forming power supply 12 set to 20 V or more. If the output voltage E0 of the forming power supply 12 and the resistance value R0 of the variable resistor 32 of the forming power supply 12 are set, the energization current I0 = E0 / R0 and the inter-electrode voltage V0 = 0 in step S0.

[0019] Next, in step S1, with a current flowing between the electrodes 22, 23, an arc A (vacuum DC arc) is generated between the electrodes 22, 23 by separating the movable electrode 23 from the fixed electrode 22 by an opening operation under conditions that satisfy certain conditions. The electrode distance D1 between the electrodes 22, 23 here is an arbitrary dimension.

[0020] When the arc A is generated in step S1, an inter-electrode voltage V1, which is a potential difference for maintaining the generation of the arc A, occurs between the electrodes 22, 23. In step S1, when the output voltage E0 and the resistance value R0 of the forming power supply 12 from step S0 are kept constant, the energization current I1 = (E0 - V1) / R0 decreases due to the generation of the arc A. This energization current I1 is 20 A or more, and it is assumed that the surface state of each electrode 22, 23 does not change even if the generation of the arc A is maintained for a long time as a current value at a level that does not cause electrode melting. Here, steps S0 and S1 constitute an arc generation step.

[0021] While maintaining the generation of the arc A in step S1, in steps S2 to S4, the electrode distance D n and the energization current I n are changed according to a plurality of conditions (modes). In the present embodiment, in each of steps S2 to S4, which are three steps, the electrode distance D n and the energization current I n are changed to three conditions. Here, steps S2 to S4 constitute an adjustment step.

[0022] In step S2, while maintaining the electrode distance D1 from step S1 as the electrode distance D2, the output voltage E2 of the chemical power supply 12 is increased, thereby amplifying the current I2 from the current I1 to an arbitrary value and allowing a certain period of time to pass. At this time, the current I2 = (E2 - V1) / R0. Here, the current I n For amplification, the output voltage E of the chemical power supply 12 n Instead of increasing the voltage, the resistance value of the variable resistor 32 may be decreased, but in this embodiment, the output voltage E of the chemical power supply 12 n This section explains how to change [the value].

[0023] In step S2, while the amplified current I2 is flowing, the inter-electrode voltage V2 increases as the chemical treatment progresses, melting the surface of the fixed electrode 22 which becomes the cathode due to the generation of arc A. After a certain period of time has elapsed since the current was amplified to I2, the chemical power supply 12 reduces the output voltage from E2 to E1 or a value close to E1, and reduces the current from I2 to I1. With the output voltage and current thus reduced, the inter-electrode distance D2 between each electrode 22, 23 is increased to the inter-electrode distance D3 as preparation for step S3.

[0024] Step S3 is carried out in the same manner as step S2, except that the conditions for the electrode distance D3 and the current I3 are different. In step S3, while maintaining the electrode distance D3 between electrodes 22 and 23, the output voltage E3 of the chemical power supply 12 is increased to amplify the current I3 from the current I2 to an arbitrary value and allow a certain period of time to pass. At this time, the current I3 = (E3 - V2) / R0.

[0025] In step S3, while the amplified current I3 is flowing, the inter-electrode voltage V3 increases as the chemical treatment of the surface of the fixed electrode 22 progresses due to the generation of arc A. After a certain period of time has elapsed since the current was amplified to I3, the chemical treatment power supply 12 reduces the output voltage from E3 to E1 or a value close to E1, and reduces the current from I3 to I1. With the output voltage and current thus reduced, the inter-electrode distance D3 is increased to D4 as preparation for step S4.

[0026] Step S4 is the last of the multiple conditions of the adjustment step to be performed. In step S4, while maintaining the distance D4 between electrodes 22 and 23, the output voltage E4 of the chemical power supply 12 is increased, thereby amplifying the current I4 from the current I3 to an arbitrary value. At this time, the current I4 = (E4 - V3) / R0.

[0027] In step S4, while the amplified current I4 is flowing, the inter-electrode voltage V4 rises in accordance with the progress of the chemical treatment of the surface of the fixed electrode 22 due to the generation of arc A. In step S4, the inter-electrode voltage V4 is measured by the voltmeter 14, and the time for which the current I4 flows is adjusted based on the inter-electrode voltage V4. Specifically, the elapsed time after the inter-electrode voltage V4 measured by the voltmeter 14 rises to a predetermined value is measured, and when this elapsed time reaches a time predetermined according to the chemical treatment of the surface of the fixed electrode 22, the output of the chemical treatment power supply 12 is stopped to extinguish the arc A between each electrode 22, 23.

[0028] As the arc A between electrodes 22 and 23, which has been continuously generated from step S1 to step S4, disappears, the inter-electrode voltage and current between electrodes 22 and 23 become 0, and then the movable electrode 23 is moved to make the inter-electrode distance between electrodes 22 and 23 0.

[0029] Upon completion of step S4, the arc generation step and adjustment step have been performed once. Subsequently, as step S5, a reversal step is performed to reverse the direction of the current of arc A flowing between electrodes 22 and 23. As a specific example, as shown in Figure 3, one method is to switch the electrode wiring on the voltage application side and the ground side using a vacuum interrupter 11, connect the wiring cable 28 to the fixed electrode 22, and connect the ground cable 26 connected to the movable electrode 23. Another example is to switch between positive and negative voltages in the DC voltage source 31 of the chemical power supply 12 and output them, as shown in Figure 4. The former method is advantageous in that the DC voltage source 31 can be miniaturized, while the latter method is advantageous in that the current chemical work can be simplified.

[0030] In step S5, after the reversal step is performed, the arc generation step and the adjustment step are performed again. That is, after reversing the direction of the current of arc A flowing between electrodes 22 and 23, steps S0 to S4 described above are performed one more time, and in the current generation method of this embodiment, the arc generation step and the adjustment step are performed twice.

[0031] According to the above embodiment, while maintaining the arc A generated in step S1 without extinguishing it, the distance between electrodes D of each electrode 22 and 23 is maintained in steps S2 to S4. n and current I n This is varied under multiple conditions. This minimizes the number of times each electrode 22 and 23 is switched on and off, thereby simplifying the current conversion process. Moreover, the distance between electrodes D n and current I n By changing this, the entire surface of each electrode 22, 23 can be adjusted to transform into a desired molten state, thereby effectively performing the current conversion treatment and improving the dielectric strength.

[0032] In step S1, which is included in the arc generation step, a DC current is passed through each electrode 22, 23 in a closed state, and by opening the electrodes while the current is still flowing, arc A, which is a vacuum DC arc, is generated. In this vacuum DC arc generation phenomenon, a potential difference is generated between each electrode 22, 23 at the moment they separate, and if this potential difference cannot be output from the chemical power supply 12, arc A cannot be generated stably. The generation of the potential difference between each electrode 22, 23 due to arc A is a phenomenon of less than a microsecond, and after the generation of arc A, the output voltage E of the chemical power supply 12 n It will no longer be able to follow changes in this setting.

[0033] Therefore, in this embodiment, a variable resistor 32 is provided in front of the DC voltage source 31 in the chemical power supply 12, and the output voltage E of the chemical power supply 12 is changed immediately before the opening operation. nThe voltage is set to 20V or higher. This generates a potential difference between electrodes 22 and 23 to maintain arc A through a change in potential distribution between the resistors and electrodes 22 and 23, and allows arc A to be generated immediately after opening the electrodes by creating a potential difference between electrodes 22 and 23.

[0034] In steps S2 to S4, which constitute the adjustment step, the current I1 is maintained or greater, and since the current I1 is 20A or greater, the current I n The current is maintained at 20A or higher. This allows metal vapor to be continuously generated from the surfaces of electrodes 22 and 23 that act as cathodes due to the localized arc current, and the generation of arc A can be stably maintained.

[0035] In the vacuum interrupter 11, the distance between electrodes D n The larger the distance between electrodes D, the easier it becomes for molten metal splatter generated by the melting of the surfaces of each electrode 22 and 23 due to arc A to diffuse. Therefore, in steps S2 to S4 which constitute the adjustment step, the distance between electrodes D n When the length is 50 mm or more, the current I n The current is set to 500A or less. By setting it in this way, molten metal splatter can be suppressed and prevented from adhering to the walls of the vacuum container 21, thereby suppressing contamination of the inside of the vacuum container 21 by metal splatter.

[0036] Furthermore, in the vacuum interrupter 11, if the surfaces of each electrode 22 and 23 are excessively melted by the arc A, the shape of the surface deforms, and the contact resistance between each electrode 22 and 23 increases. Therefore, in each of the steps S2 to S4 that constitute the adjustment step, the energizing current I n The current I n The value obtained by multiplying the time the current flows by the value is set to 1500 A·sec or less. By setting it in this way, it is possible to prevent excessive melting of the surfaces of each electrode 22 and 23 by arc A, and to suppress the increase in contact resistance between each electrode 22 and 23 due to excessive melting.

[0037] Furthermore, since the inversion step is performed, each electrode 22 and 23 is subjected to current conversion treatment as both the anode and cathode. When current conversion treatment is performed with arc A, which is a vacuum DC arc, the current conversion state will differ between the anode and cathode. However, in this embodiment, the current conversion treatment can be made uniform on both electrodes 22 and 23, thereby improving the withstand voltage performance.

[0038] It should be noted that the present invention is not limited to the embodiments described above, and can be implemented with various modifications. In the embodiments described above, the size, shape, orientation, etc., shown in the accompanying drawings are not limited thereto, and can be appropriately modified within the scope that allows the present invention to exert its effects. Furthermore, it can be implemented with appropriate modifications as long as it does not deviate from the scope of the objectives of the present invention.

[0039] For example, in the above embodiment, the distance D between electrodes in the adjustment step. n and current I n This was conducted with three conditions, but it is also possible to use two, four or more conditions.

[0040] In addition, the inter-electrode distance D is adjusted in the adjustment step. n and current I n In order to create multiple conditions, in the above embodiment, the electrode distances D2, D3, and D4 for each condition were set to different distances, and the currents I2, I3, and I4 were changed to different current values, but the invention is not limited to this. Between each condition, the electrode distance D n The values ​​are different, and the current I n If they are the same, or the distance between electrodes D n If the same and the current I n Even if the conditions are different, it will still be considered a change in conditions. For example, in the multiple conditions of the adjustment step, the electrode distance may be fixed at a single value of 10 mm, and the current may be changed in stages from 20 A to 500 A as part of the current conversion treatment.

[0041] Furthermore, in the adjustment step of the above embodiment, the inter-electrode voltage V n Based on the current I nAlthough this was only performed under the condition (step S4) where the timing of the current flow is adjusted at the end, the same procedure was followed under other conditions as well. n You can adjust the timing of when it plays.

[0042] Furthermore, the inversion step in the above embodiment may be omitted insofar as the current conversion treatment of the pair of electrodes 22 and 23 can be effectively carried out. [Explanation of Symbols]

[0043] 11: Vacuum interrupter 12: Chemical power supply (DC power supply) 21: Vacuum container 22: Fixed electrode (electrode) 23: Movable electrode (electrode) A: Arc

Claims

1. A method for currentizing a vacuum interrupter, comprising opening a pair of electrodes of a vacuum interrupter connected to a DC power supply to generate an arc and thereby currentizing the electrodes, An arc generation step in which a DC voltage is applied to the vacuum interrupter from the DC power supply and an arc is generated by an opening operation that separates one electrode from the other electrode, A method for generating current in a vacuum interrupter, characterized by performing an adjustment step in which the distance between one electrode and the other electrode and the current being supplied are changed to multiple conditions while maintaining the generation of the arc in the arc generation step.

2. The method for generating current in a vacuum interrupter according to claim 1, characterized in that the output voltage of the DC power supply is set to 20V or more immediately before the opening operation in the arc generation step.

3. The method for current conversion of a vacuum interrupter according to claim 1, characterized in that the current is maintained at 20 A or more in the adjustment step.

4. The method for current conversion of a vacuum interrupter according to claim 1, characterized in that, in the adjustment step, when the distance between the electrodes is 50 mm or more, the current is set to 500 A or less.

5. The method for current conversion of a vacuum interrupter according to claim 1, characterized in that, in each of the conditions of the adjustment step, the value obtained by multiplying the energizing current by the time the energizing current is passed is 1500 A·sec or less.

6. The method for current conversion of a vacuum interrupter according to claim 1, characterized in that, in the adjustment step, the inter-electrode voltage between one electrode and the other electrode is measured, and the time for which the current flows is adjusted based on the inter-electrode voltage in at least the last of the multiple conditions to be performed.

7. A method for generating current in a vacuum interrupter according to any one of claims 1 to 6, characterized in that, after performing the arc generation step and the adjustment step once, a reversal step is performed to reverse the direction of the arc current flowing between the electrodes, and then the arc generation step and the adjustment step are performed again.

Images