Method for detecting the vacuum level of a vacuum interrupter

Abstract

To provide a method for electrochemical treatment of electrodes that can be carried out simply and effectively. [Solution] The vacuum level detection method of the present invention detects the vacuum level of a vacuum interrupter (11) having a fixed electrode (22) and a movable electrode (23) inside the vacuum container (21). The method includes an arc generation step S0, S1 in which a DC voltage is applied to the vacuum interrupter from a DC power supply and an arc (A) is generated by opening the electrodes to separate them; a measurement step S2 in which an arc maintenance voltage is measured while maintaining the arc generation from the arc generation step; and a detection step S3 in which the vacuum level is detected based on the arc maintenance voltage measured in the measurement step and master data of the vacuum level.

Description

[Technical Field]

[0001] This invention relates to a method for detecting the vacuum level of a vacuum interrupter. [Background technology]

[0002] Patent Document 1 describes a vacuum valve comprising a detection electrode provided on the outer wall of the vacuum valve and a detection unit connected to the detection electrode, which detects a discharge signal caused by a discharge occurring inside the vacuum valve during operation and performs a determination of whether the vacuum level of the vacuum valve is insufficient. Patent Document 2 describes a vacuum circuit breaker that generates a magnetic field by winding a magnetic field cable around it and applying a predetermined DC voltage, thereby creating a magnetron state between the electrodes of the vacuum circuit breaker and measuring the vacuum level of the vacuum circuit breaker. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 64-76630 [Patent Document 2] Japanese Patent Publication No. 2017-216134 [Overview of the project] [Problems that the invention aims to solve]

[0004] In Patent Document 1, the vacuum level is constantly monitored during operation, so the vacuum level cannot be detected in the pressure range of 1.0 Pa or less. Furthermore, the vacuum level management standard that guarantees the normal operation of the vacuum interrupter is 6.7 × 10⁻⁶. -2 Since it is Pa, it becomes impossible to detect the degree of vacuum in a way that would allow for the determination of such a standard. Furthermore, as described in Patent Document 2, when a vacuum circuit breaker is installed on-site, it becomes difficult to attach the magnetic field cable due to reasons such as the lack of space to wind the magnetic field cable around it.

[0005] This invention has been made in view of the above circumstances, and aims to provide a vacuum level detection method for a vacuum interrupter that can detect the vacuum level under the conditions of a vacuum level control standard while having a simple configuration. [Means for solving the problem]

[0006] One embodiment of the present invention is a method for detecting the vacuum degree of a vacuum interrupter, which detects the vacuum degree of a vacuum container in a vacuum interrupter having a pair of electrodes in the vacuum container, and is characterized by performing an arc generation step of applying a DC voltage from a DC power supply to the vacuum interrupter and generating an arc by opening the electrodes to separate one electrode from the other; a measurement step of measuring an arc maintenance voltage that maintains the generation of the arc while maintaining the generation of the arc in the arc generation step; and a detection step of detecting the vacuum degree based on the arc maintenance voltage measured in the measurement step and predetermined comparison data of the vacuum degree. [Effects of the Invention]

[0007] According to the present invention, in the comparative data of vacuum levels, the relationship between the arc-sustaining voltage that maintains the arc generated by the DC voltage and the vacuum level is 10 -3 Pa or more 10 2 Since there is a negative proportional relationship within the range of Pa or less, the vacuum level control standard conditions (6.7 × 10) that guarantee the normal operation of the vacuum interrupter are met. -2 The degree of vacuum can be detected by its relationship to the pressure (Pa). Furthermore, since the degree of vacuum is detected by measuring the arc maintenance voltage and comparing it with comparison data, the installation of conventional detection electrodes and magnetic field cables mentioned above is unnecessary, thus simplifying the configuration used for vacuum detection. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing the configuration of the vacuum level detection circuit of the vacuum interrupter in the embodiment. [Figure 2] This is a flowchart of the vacuum level detection method according to the embodiment. [Figure 3] This graph shows an example of the master data used in the detection step. [Modes for carrying out the invention]

[0009] The vacuum level detection method for a vacuum interrupter according to the embodiment will be described in detail below with reference to the attached drawings. Note that the present invention is not limited to the embodiments described below, and can be modified as appropriate without changing its essence. The orientation of each component in the following embodiments is merely an example and can be changed to any orientation.

[0010] Figure 1 is a diagram showing the configuration of a vacuum level detection circuit for a vacuum interrupter in an embodiment. As shown in Figure 1, the circuit for implementing the vacuum level detection method of this embodiment includes a vacuum interrupter 11, a DC power supply 12, an ammeter 13, and a voltmeter 14.

[0011] The vacuum interrupter 11 comprises a vacuum vessel 21 whose interior is maintained under vacuum, and a pair of electrodes 22 and 23 housed within the vacuum vessel 21. Of the pair of electrodes 22 and 23, one is a fixed electrode 22 and the other is a movable electrode 23. In Figure 1, the movable electrode 23 is capable of opening and closing vertically via an opening and closing mechanism (not shown). When the movable electrode 23 comes into contact with the fixed electrode 22 due to this movement, it closes, and when it separates, it opens. The distance between the fixed electrode 22 and the movable electrode 23 in the open state is the electrode distance D. n (n is a non-negative integer, and so on)

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

[0013] The DC power supply 12 connects the DC voltage source 31 and the load resistor 32 in a series circuit, and the output voltage E nand the output current can be made variable. The DC power supply 12 has the cathode side of the DC voltage source 31 grounded and is 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 DC power supply 12 serves as the cathode, and the movable electrode 23 serves as the anode.

[0014] The ammeter 13 is provided on the wiring cable 28 and measures the energization current I n that energizes the vacuum interrupter 11 by the DC power supply 12. Note that the energization current I n is set to the same value as the output current of the DC power supply 12 and is also set to the same value as the current value flowing between the fixed electrode 22 and the movable electrode 23.

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

[0016] In the present embodiment, an opening / closing mechanism (not shown) for driving the movable electrode 23, a DC power supply 12, an ammeter 13, and a control unit (not shown) connected to the voltmeter 14 can be provided. The control unit is composed of a processor that executes various processes, a memory that stores programs, and the like. Based on the programs stored in the memory of the control unit and the outputs of the ammeter 13 and the voltmeter 14, the opening / closing mechanism and the DC power supply 12 may be controlled to implement the vacuum degree detection method described later.

[0017] Subsequently, a vacuum degree detection method for detecting the vacuum degree of the vacuum vessel using the circuit of FIG. 1 will be described with reference to FIG. 2. FIG. 2 is a flowchart in the vacuum degree detection method of the embodiment. The vacuum degree detection method of the present embodiment is implemented in the order of step S0, step S1, step S2, and step S3 as described below, and steps S0 to S3 correspond to S0 to S3 shown in FIG. 2. Note that the main body that operates the DC power supply 12 and the like in each step described later may be implemented by the above-described control unit or may be performed by an operator.

[0018] In the initial step S0, the electrodes 22 and 23 of the vacuum interrupter 11 connected to the DC power supply 12 are closed. Then, immediately before the opening operation of electrodes 22 and 23, a DC voltage is applied to the vacuum interrupter 11 from the DC power supply 12 with an output voltage E0 of 20V or more. If the output voltage E0 of the DC power supply 12 and the resistance value R of the load resistor 32 of the DC power supply 12 are taken, then the current I0 = E0 / R and the voltage between electrodes V0 = 0 in step S0.

[0019] Next, in step S1, with current flowing between electrodes 22 and 23, an opening operation is performed to separate the movable electrode 23 from the fixed electrode 22, thereby satisfying certain conditions and generating an arc A (vacuum DC arc) between electrodes 22 and 23.

[0020] When arc A is generated in step S1, an inter-electrode voltage V1 is generated between each electrode 22, 23, which is a potential difference necessary to maintain the generation of arc A. In step S1, if the output voltage E0 of the DC power supply 12 from step S0 is kept constant, the current I1 decreases to (E0-V1) / R due to the generation of arc A. This current I1 is 20A or more, and is a current value that does not cause electrode melting, so that even if the generation of arc A is maintained for a long time, the surface state of each electrode 22, 23 will not change. Herein, steps S0 and S1 constitute the arc generation step.

[0021] After step S1, a measurement step is performed as step S2. In step S2, while maintaining the generation of arc A as in step S1, the output voltage E2 of the DC power supply 12 is adjusted to decrease and the value of the current I2 is adjusted. At this time, the current I2 = (E2 - V1) / R. During the generation of arc A in step S2, the output voltage E2 applied from the DC power supply 12 is kept constant. By adjusting the output voltage E2 of the DC power supply 12, the current I2 is adjusted to the same current value as under the conditions for acquiring the master data (comparison data) described later.

[0022] In step S2, the adjusted current I2 is applied for a certain period of time, and then the inter-electrode voltage V2 is measured by the voltmeter 14 while the current I2 is kept constant within the range of 20A to 50A. In other words, the adjusted current I2 is kept constant when measuring the inter-electrode voltage V2. The measured inter-electrode voltage V2 is then recorded as the arc-maintaining voltage VA that sustains the generation of arc A in the vacuum interrupter 11.

[0023] After recording the arc-maintaining voltage VA, the output of the DC power supply 12 is stopped to extinguish the arc A between electrodes 22 and 23. As the arc A generated between electrodes 22 and 23 between step S1 and step S2 is extinguished, 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.

[0024] After step S2, a detection step is performed as step S3. Figure 3 is a graph showing an example of master data used in the detection step. In the graph of Figure 3, the vertical axis represents the arc maintenance voltage between each electrode 22 and 23, and the horizontal axis represents the internal pressure of the vacuum vessel 21. This internal pressure is the degree of vacuum in the vacuum vessel 21 in the vacuum interrupter 11.

[0025] In step S3, the master data shown in Figure 3, which serves as predetermined comparison data for vacuum levels, is used. This master data is a graph plotted by measuring the relationship between the internal pressure of the vacuum vessel 21 and the arc-sustaining voltage that maintains the generation of arc A between each electrode 22 and 23, before implementing this detection method.

[0026] In step S3, the vacuum level of the vacuum vessel 21 is detected based on the arc-maintaining voltage VA measured and recorded in step S2 (measurement step) and the master data in Figure 3. In this embodiment, in step S3, the recorded arc-maintaining voltage VA is fitted to the graph of the master data in Figure 3 to estimate the internal pressure of the vacuum vessel 21. Generally, the vacuum level control standard that guarantees the normal operation of a vacuum interrupter is 6.7 × 10⁻⁶. -2 It is given as Pa. Therefore, the reference value is 6.7 × 10-2 The vacuum leak state of the vacuum vessel 21 is detected (determined) by comparing Pa with the estimated internal pressure described above. For example, the reference value is 6.7 × 10⁻⁶. -2 If the internal pressure estimated from Pa is small, it is determined that the vacuum level is sufficient to guarantee normal operation, and the standard value is 6.7 × 10⁻⁶. -2 If the internal pressure estimated from Pa is high, it is detected as a vacuum level that cannot guarantee normal operation. At the arc maintenance voltage VA shown in Figure 3, the internal pressure of the vacuum vessel 21 is 1.0 × 10⁻⁶ -2 It is estimated to be Pa, with a reference value of 6.7 × 10⁻⁶. -2 Since it is smaller than Pa, it is detected as a vacuum level that can guarantee normal operation.

[0027] Here, in step S3, the internal pressure (vacuum level) of the vacuum vessel 21 in the master data (comparison data) is 10 -3 Pa or more 10 2 A range of Pa or less is used. Within this range, as shown in the master data graph in Figure 3, the internal pressure and arc sustaining voltage are in a negative proportional relationship, and the accuracy of the internal pressure estimated by fitting the measured arc sustaining voltage VA is good.

[0028] According to the above embodiment, the internal pressure of the vacuum vessel 21 can be estimated using the measured value of the arc-maintaining voltage (inter-pole voltage V2) that maintains the arc A generated by the DC power supply 12 and the master data in Figure 3. Furthermore, the estimated internal pressure of the vacuum vessel 21 and the reference value 6.7 × 10⁻⁶ can be used. -2 The vacuum level can be detected based on its relationship to Pa. This allows the vacuum level to be detected under the conditions of the vacuum level control standard that guarantees the normal operation of the vacuum interrupter 11.

[0029] Furthermore, since the vacuum level is detected by measuring the arc maintenance voltage and comparing it with master data, the installation of conventional detection electrodes and magnetic field cables mentioned above is unnecessary, thus simplifying the configuration used for vacuum level detection.

[0030] 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 DC power supply 12, it becomes impossible to generate arc A 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 DC power supply 12 n It will no longer be able to follow changes in this setting.

[0031] Therefore, in this embodiment, a load resistor 32 is provided in front of the DC voltage source 31 in the DC power supply 12, and the output voltage E of the DC power supply 12 is set immediately before the opening operation. n The 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.

[0032] Furthermore, in step S2, which is the measurement step, the current I2 is kept constant within the range of 20A to 50A. This allows metal vapor to be continuously generated from the surface of electrodes 22 and 23 that become cathodes due to the localized arc current, and the generation of arc A can be stably maintained.

[0033] 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.

[0034] For example, in the above embodiment, the comparison data was set to the master data shown in Figure 3, but this does not preclude the use of data other than such master data.

[0035] Also, the current I n This adjustment may also be performed by replacing the load resistor 32 with a variable resistor and adjusting its resistance value. [Explanation of Symbols]

[0036] 11: Vacuum interrupter 12:DC power supply 21: Vacuum container 22: Fixed electrode (electrode) 23: Movable electrode (electrode) A: Ark

Claims

1. A method for detecting the vacuum level of a vacuum interrupter having a pair of electrodes inside a vacuum container, the vacuum level of the vacuum container in the vacuum interrupter, An arc generation step is performed by applying a DC voltage from a DC power supply to the vacuum interrupter and generating an arc by opening the electrodes and separating one electrode from the other. A measurement step that measures the arc-maintaining voltage while maintaining the generation of the arc in the arc generation step, A method for detecting the vacuum degree of a vacuum interrupter, characterized by performing a detection step of detecting the vacuum degree based on the arc maintenance voltage measured in the measurement step and predetermined comparison data of the vacuum degree.

2. The vacuum level detection method for a vacuum interrupter according to claim 1, characterized in that, when measuring the arc maintenance voltage in the measurement step, the value of the current supplied between the electrodes is kept constant.

3. The vacuum level detection method for a vacuum interrupter according to claim 2, characterized in that, in the measurement step, the DC voltage applied from the DC power supply is kept constant while the arc is being generated.

4. The vacuum level detection method for a vacuum interrupter according to claim 2, characterized in that the current value is kept constant within the range of 20A to 50A in the measurement step.

5. The vacuum level detection method for 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.

6. In the detection step, the vacuum level in the comparison data is 10 －３ Pa or more 10 ２ A method for detecting the vacuum level of a vacuum interrupter according to any one of claims 1 to 5, characterized in that a range of Pa or less is used.

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