JP6600567B2 - Vacuum valve vacuum degree monitoring device and monitoring method - Google Patents

Description

  Embodiments described herein relate generally to a vacuum valve monitoring device and a monitoring method for a vacuum valve that monitors the vacuum of a vacuum valve having a pair of contactable and separable contacts.

  The vacuum valve which has the outstanding interruption | blocking performance and insulation performance is used for the vacuum circuit breaker used for a power distribution equipment. However, when the degree of vacuum deteriorates, it becomes difficult to exhibit these performances.

  For this reason, there have been many proposals for monitoring the degree of vacuum. For example, what detects the discharge which generate | occur | produces with deterioration of a vacuum degree with an antenna is known (for example, refer patent document 1). However, although noise removal is performed by detecting the continuity and duration of discharge, there is a limit to improving the detection sensitivity because external noise is easily superimposed and it is difficult to distinguish from discharge in the vacuum bulb. In addition, there is known one that performs noise removal by providing a threshold value for a signal detected by an antenna (see, for example, Patent Document 2). However, it is difficult to detect a weak discharge below the threshold, and there is a limit to improving detection sensitivity.

  In addition, there is known one that detects an electromagnetic wave by installing an antenna close to a vacuum valve (see, for example, Patent Document 3). However, a bandpass filter is used for signal processing, and the microwave band generated as the degree of vacuum is deteriorated is detected. Therefore, the frequency band to be detected is limited, and there is a limit to improving the detection sensitivity. . Further, there is known a technique in which external discharge that becomes noise is attenuated by a low-pass filter, and internal discharge from a vacuum bulb is received by an antenna (see, for example, Patent Document 4). However, since a high frequency band of several MHz to several hundred MHz is detected and a threshold value is provided for determining the degree of vacuum deterioration, it is difficult to detect discharge that falls below the threshold value, and there is a limit to improving detection sensitivity. was there.

  Furthermore, there is known one that detects electromagnetic waves from a vacuum valve with an antenna, analyzes the frequency of the signal, and estimates the degree of vacuum (for example, see Patent Document 5). However, the phase of the voltage applied to the main circuit is divided into a plurality of parts, and frequency analysis is performed for each of the divided phases, so that the analysis apparatus is complicated.

  For this reason, without using a complicated device that divides the phase of the applied voltage, the electromagnetic wave detected by the antenna is frequency-analyzed by a simple method, and a filter or the like is connected to the circuit for noise removal, or judgment There has been a demand for a sensor that can detect the degree of vacuum of a vacuum valve with high sensitivity without providing a threshold value or the like.

JP 2002-184275 A JP 2005-302331 A JP-A-7-318447 Japanese Patent No. 5597311 Japanese Patent Laying-Open No. 2015-15172

  The problem to be solved by the present invention is that the electromagnetic wave generated from the vacuum valve can be directly detected with high sensitivity by the antenna without using a filter or a threshold, and the degree of vacuum can be monitored. An object of the present invention is to provide a vacuum degree monitoring device and a monitoring method for a vacuum valve.

  In order to solve the above-described problem, a vacuum degree monitoring device for a vacuum valve according to an embodiment includes an electromagnetic wave detection sensor disposed at a predetermined interval on a vacuum valve, and a vacuum degree determination device connected to the electromagnetic wave detection sensor. The vacuum degree determination device includes: an electromagnetic wave detection unit that obtains a peak voltage value of the electromagnetic wave detected by the electromagnetic wave detection sensor and a rise time of the first wave; and a rise time of the peak voltage value and the first wave. A waveform comparison unit that compares with a previously obtained vacuum degree curve, and a vacuum degree determination unit that determines the degree of vacuum of the vacuum valve based on the determination by the waveform comparison unit. .

Schematic which shows the structure of the vacuum degree monitoring apparatus of the vacuum valve which concerns on Example 1 of this invention. The figure explaining the relationship between the vacuum degree which concerns on Example 1 of this invention, and the peak voltage value of a signal. The figure explaining the relationship between the vacuum degree which concerns on Example 1 of this invention, and the rise time of a signal. The figure explaining the relationship between the peak voltage value of the signal which concerns on Example 1 of this invention, and a rise time. The measurement example of the electromagnetic wave which concerns on Example 1 of this invention. The figure explaining the angle of the electromagnetic wave detection sensor which concerns on Example 1 of this invention. The figure explaining the relationship between the angle of the electromagnetic wave detection sensor which concerns on Example 1 of this invention, and an output voltage. Schematic which shows the structure of the vacuum degree monitoring apparatus of the vacuum valve which concerns on Example 2 of this invention. The figure explaining the relationship between the applied voltage and discharge pulse which concern on Example 2 of this invention. Schematic which shows the structure of the vacuum degree monitoring apparatus of the vacuum valve which concerns on Example 3 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a vacuum degree monitoring device for a vacuum valve according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing a configuration of a vacuum degree monitoring device for a vacuum valve according to a first embodiment of the present invention, and FIG. 2 shows a vacuum degree and a signal according to the first embodiment of the present invention. FIG. 3 is a diagram for explaining the relationship between the degree of vacuum and the signal rise time according to the first embodiment of the present invention, and FIG. 4 is a signal for explaining the relationship between the peak voltage values of the first embodiment of the present invention. FIG. 5 illustrates an example of electromagnetic wave measurement according to the first embodiment of the present invention, and FIG. 6 illustrates an angle of the electromagnetic wave detection sensor according to the first embodiment of the present invention. FIG. 7 is a diagram for explaining the relationship between the angle and the output voltage of the electromagnetic wave detection sensor according to the first embodiment of the present invention.

  As shown in FIG. 1, a vacuum valve 2 mounted on a vacuum circuit breaker is housed in a metal box 1. An electromagnetic wave detection sensor 3 such as a loop antenna is disposed in the vacuum valve 2 in the vicinity thereof. The output of the electromagnetic wave detection sensor 3 is connected to a vacuum degree determination device 4 provided outside the box 1. The degree-of-vacuum determination device 4 includes an electromagnetic wave detection unit 5 that detects the peak voltage value of the electromagnetic wave connected to the output of the electromagnetic wave detection sensor 3 and the rise time of the first wave, and the electromagnetic wave detected by the electromagnetic wave detection unit 5 as a vacuum degree curve. A waveform comparison unit 6 to be compared and a vacuum level determination unit 7 that determines deterioration of the vacuum level based on information in the waveform comparison unit 6 are configured.

  Next, the relationship between the electromagnetic wave detected by the electromagnetic wave detection sensor and the degree of vacuum will be described with reference to FIGS. Each figure is a logarithmic scale.

  When the degree of vacuum in the container of the vacuum bulb 2 is changed and an electromagnetic wave due to discharge is detected by a loop antenna, the peak voltage value of the electromagnetic wave increases when the degree of vacuum deteriorates and approaches atmospheric pressure as shown in FIG. . Although the peak voltage value is easily formed in the first wave, it is not limited to the first wave. Further, as shown in FIG. 3, when the degree of vacuum deteriorates and approaches atmospheric pressure, the rise time of the first wave is shortened.

As a result, the relationship between the peak voltage value of the electromagnetic wave and the rise time of the first wave increases as the rise time of the first wave becomes shorter, as shown in FIG. That is, it is possible to obtain a vacuum degree curve in which the rise time of the first wave and the peak voltage value change according to the change in the degree of vacuum. On this vacuum degree curve, plotting a value at a degree of vacuum (10 ⁻¹ Pa or less) at which the discharge start voltage rises and stabilizes from a known Passenger curve gives point A (20 mV, 0.5 μS). Point A is an electromagnetic wave from a typical vacuum valve 2.

  The values obtained when the degree of vacuum as shown in FIGS. 5A and 5B is changed are plotted on the vacuum degree curve shown in FIG. These data are obtained by obtaining the peak voltage and rise time of the electromagnetic wave directly detected by the electromagnetic wave detection sensor 3 without using a filter or the like. Since the electromagnetic wave detection sensor 3 has directivity and detects a magnetic field component that is difficult to shield at a high frequency as compared with an electric field, it has high sensitivity. The frequency band is 30 kHz to 200 MHz based on vacuum discharge (from low vacuum to high vacuum).

  Since the peak voltage value of the electromagnetic wave generated with the change in the degree of vacuum and the rise time of the first wave vary depending on the discharge part such as the arc shield and the electrode, a vacuum degree curve at a representative discharge part is obtained in advance. Shall be kept. The general vacuum valve 2 has a good degree of vacuum when the rise time is 0.5 μS or more and the peak voltage value is 20 mV or less. Here, when no electromagnetic wave is generated, the degree of vacuum is very good.

  Next, the output change of the electromagnetic wave detection sensor 3 will be described with reference to FIGS.

  As shown in FIG. 6, when the cross section of the entire loop of the electromagnetic wave detection sensor 3 is arranged perpendicular to the axial direction of the vacuum valve 2 and the angle θ is changed, the output voltage is a cosine curve as shown in FIG. It becomes. Here, in this type of device in which noise is generally easily superimposed, it is sufficient to suppress the measurement error to 1%. When the output voltage is to be within this measurement error, the angle of the electromagnetic wave detection sensor 3 is θ = ± 8 degrees may be changed, and workability can be improved. Moreover, the cross section of the entire loop of the electromagnetic wave detection sensor 3 with respect to the axial direction of the vacuum valve 2 can also be arranged at ± 8 degrees. In addition, the electromagnetic wave detection sensor 3 secured a sufficient distance to prevent discharge from starting from the vacuum bulb 2.

  These are referred to as a twisted arrangement of the cross section of the electromagnetic wave detection sensor 3 at a predetermined angle with respect to the axial direction of the vacuum valve 2.

  According to the vacuum degree monitoring device of the vacuum valve of the first embodiment, the electromagnetic wave generated with the discharge of the vacuum bulb 2 is detected by the electromagnetic wave detection sensor 3, and the peak voltage value and the first wave of the first wave are detected by the vacuum degree measuring device 4. Since the rise time is obtained and the degree of vacuum is judged in comparison with the previously obtained degree of vacuum curve, the degree of vacuum of the vacuum valve 2 can be monitored with high sensitivity without the need for a noise removal filter or the like. Can do. Moreover, in the vacuum degree measuring apparatus 4, since it is sufficient to detect only the peak voltage value and the rise time of the first wave, the analysis apparatus can be simplified.

  Next, a vacuum valve vacuum degree monitoring apparatus according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 8 is a schematic diagram showing the configuration of a vacuum degree monitoring device for a vacuum valve according to Embodiment 2 of the present invention, and FIG. 9 is a diagram for explaining the relationship between the applied voltage and the discharge pulse according to Embodiment 2 of the present invention. is there. The second embodiment is different from the first embodiment in that a current transformer is provided in the main circuit to determine discharge. In FIG. 8, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 8, an annular CT 8 is provided around the vacuum valve 2 at a predetermined interval, and is connected to the vacuum degree determination device 4 via a voltage divider 9. As shown in FIG. 9, the degree-of-vacuum determination device 4 takes out the operating voltage element of the main circuit and detects the superimposed current signal due to the discharge detected at CT8.

  Thereby, since the superimposition signal by discharge is detected with the monitoring of the degree of vacuum, the degree of vacuum can be reliably monitored. In the three-phase circuit, the phase of the operating voltage is different, so that the phase can be specified. Further, in the discharge of the vacuum valve 2, since a pulsed superimposed signal having the same polarity is output in the vicinity of the zero cross phase of the operating voltage, it is easy to determine the deterioration of the degree of vacuum.

  According to the vacuum degree monitoring device for a vacuum valve of the second embodiment, in addition to the effects of the first embodiment, the degree of vacuum can be detected more reliably.

  Next, a vacuum valve vacuum degree monitoring apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 10 is a schematic diagram illustrating a configuration of a vacuum degree monitoring device for a vacuum valve according to Embodiment 3 of the present invention. The third embodiment is different from the first embodiment in that a voltage divider is provided in the main circuit to determine the discharge. In FIG. 10, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 10, a VT 10 is provided around the vacuum valve 2 at a predetermined interval, and is connected to the vacuum degree determination device 4 via a voltage divider 9 such as C sharing. In the degree-of-vacuum determination device 4, the operation voltage element of the main circuit is taken out as in FIG.

  According to the vacuum degree monitoring device for a vacuum valve of the third embodiment, the same effect as that of the second embodiment can be obtained.

  According to the embodiment as described above, the peak voltage value of the electromagnetic wave generated by the discharge from the vacuum bulb and the rise time of the first wave are directly detected by the electromagnetic wave detection sensor, and the previously obtained vacuum degree curve is obtained. Since the degree of vacuum is determined by placing it, it is difficult to superimpose noise, and the degree of vacuum can be monitored with high sensitivity with a simple device that does not require a filter or the like.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Box body 2 Vacuum valve 3 Electromagnetic wave detection sensor 4 Vacuum degree determination apparatus 5 Electromagnetic wave detection part 6 Waveform comparison part 7 Vacuum degree determination part 8 CT
9 Voltage divider 10 VT

Claims (8)

An electromagnetic wave detection sensor arranged at a predetermined interval in a vacuum valve;
A degree of vacuum determination device connected to the electromagnetic wave detection sensor,
The vacuum degree determination device includes an electromagnetic wave detection unit that obtains a peak voltage value of an electromagnetic wave detected by an electromagnetic wave detection sensor and a rise time of the first wave;
A waveform comparison unit that compares the peak voltage value and the rise time of the first wave with a previously obtained vacuum curve;
A vacuum degree monitoring device for a vacuum valve, comprising: a vacuum degree determination unit that determines a vacuum degree of the vacuum valve based on the determination in the waveform comparison unit.   The vacuum degree monitoring device for a vacuum valve according to claim 1, wherein the electromagnetic wave detection sensor is a loop antenna having a frequency band of 30 kHz to 200 MHz.   3. The vacuum valve according to claim 1, wherein the degree of vacuum of the vacuum valve is determined when the peak voltage value is a predetermined value or less and the rising time of the first wave is a predetermined value or more. Vacuum monitoring device.   4. The vacuum valve monitoring device according to claim 1, wherein a section of the electromagnetic wave detection sensor is twisted and arranged at a predetermined angle with respect to an axial direction of the vacuum valve. 5.   The vacuum valve vacuum degree monitoring device according to any one of claims 1 to 4, wherein a voltage divider for taking out a voltage element of an operating voltage is provided in the vacuum valve at a predetermined interval. An electromagnetic wave detection sensor is arranged at a predetermined interval in the vacuum valve,
First, the peak voltage value of the electromagnetic wave detected by the electromagnetic wave detection sensor and the rise time of the first wave are obtained,
Next, the degree of vacuum of the vacuum valve is determined by comparing the peak voltage value and the rise time of the first wave with a previously obtained degree of vacuum curve. Vacuum degree monitoring method.   The vacuum degree monitoring method for a vacuum degree monitoring apparatus for a vacuum valve according to claim 6, wherein the degree of vacuum is good when the peak voltage value is 20 mV or less and the rise time of the first wave is 0.5 µS or more. .   The vacuum degree monitoring method for a vacuum degree monitoring device for a vacuum valve according to claim 6 or 7, wherein a cross section of the electromagnetic wave detection sensor is arranged within ± 8 degrees with respect to an axial direction of the vacuum valve. .