JP4474536B2 - High voltage measuring device - Google Patents

Description

  The present invention relates to a high voltage measuring device using a Pockels material.

  In order to measure a high voltage (for example, a voltage of 1000 V or more), the withstand voltage of the measuring device and the leakage current through the measuring device are problematic. Therefore, in general, the high voltage is converted into a low voltage that is easy to measure. It is measured after. As practical high-voltage measuring instruments, instrument transformers, resistance voltage dividers, and capacitive voltage dividers have been developed.

  However, an instrument transformer can usually measure only an alternating voltage having a frequency higher than a commercial frequency. In addition, the high voltage waveform that can be measured by the resistance voltage divider and the capacitive voltage divider is considerably limited.

  Furthermore, the voltage division ratio (ratio of conversion from high voltage to low voltage) in the case of using partial pressure changes depending on conditions such as weather conditions and the arrangement of surrounding structures. For this reason, in this method, absolute measurement of voltage cannot be expected in principle.

  In recent years, a voltage measuring device using a Pockels material (referring to a substance having a Pockels effect) and a capacitive voltage divider has been developed. However, even in this technique, since a capacitive voltage divider is used, absolute measurement of voltage is difficult.

  In addition, a technique for measuring voltage with Pockels material without using a capacitive voltage divider has been developed. However, in the conventional apparatus, in order to ensure insulation between two points, a Pockels material is stored in an extremely large container and then a gas having high insulating properties is enclosed, and there is a problem that the apparatus is large. .

  Further, when performing voltage measurement using a Pockels material, in the conventional technique, light is input avoiding the position of the electrode, and the voltage is calculated from the change in the polarization state of the light. In this technique, light passes through a region adjacent to a voltage application portion (that is, a portion sandwiched between electrodes). Then, due to the proximity effect caused by the surrounding environment, there is a problem that the lines of electric force are applied from the outside or the lines of electric force escape, and the accuracy of voltage measurement is deteriorated.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a high voltage measuring apparatus capable of accurately and easily performing absolute voltage measurement.

  The high voltage measuring apparatus according to the present invention includes a light emitting unit, a detecting unit, and a sensor unit. The sensor unit includes a Pockels material, a first electrode, and a second electrode. The Pockels material has a first end and a second end. The first electrode is attached in contact with the first end. The first electrode is transparent to the light from the light emitting unit. The second electrode is attached in contact with the second end. The light emitting unit is configured to irradiate the light so that light from the light emitting unit passes through the first electrode and the Pockels material and reaches the second electrode. The detection unit measures a voltage applied between the first electrode and the second electrode based on a characteristic change of light passing through the Pockels material and reaching the second electrode. ing.

  The light characteristic change is, for example, a change in the polarization plane of the light.

  The high voltage measuring device may further include an attachment portion. The attachment portion is attached to the sensor portion, is formed in a hook shape, and has conductivity. Further, the attachment portion is electrically connected to one of the first electrode and the second electrode. The other of the first electrode and the second electrode is electrically connected to a reference potential.

  The second electrode may be transparent to light from the light emitting unit.

  In the high-voltage measuring device, the second electrode is made of a material that reflects light from the light emitting unit, the detection unit passes through the Pockels material and reaches the second electrode, and further, the second electrode The voltage may be measured based on the light reflected by and passed through the first electrode.

  The first electrode and the second electrode may be formed in contact with the entire surface of the first end and the second end.

  The Pockels material may be formed in a column shape.

  In the high-voltage measuring device, the light from the light emitting unit may be phase-modulated, and the detection unit may detect the light from the light emitting unit by synchronous detection.

  In the high voltage measurement device, the light emitted from the light emitting unit includes light of a plurality of wavelengths, and the detection unit is configured to change the first electrode based on respective characteristic changes in the light of the plurality of wavelengths. And a voltage applied between the second electrode and the second electrode may be measured.

  The Pockels material may be configured to be held in the air by attaching the attachment portion to a measurement site.

The high voltage measurement method according to the present invention comprises the following steps:
(1) A step of applying a voltage between the first electrode and the second electrode respectively formed on the first end and the second end of the Pockels material;
(2) Before or after the step (1) or at the same time, the Pockels material is irradiated with light in a portion where the voltage is applied and in a region sandwiched between the first electrode and the second electrode. Transmitting step;
(3) A step of measuring the applied voltage based on a characteristic change of light transmitted through the Pockels material.

  According to the present invention, measurement light can pass through a region sandwiched between the first electrode and the second electrode (that is, a region to which a voltage is applied). For this reason, the electric lines of force do not increase or decrease due to the proximity effect. Therefore, according to the present invention, absolute voltage measurement can be performed with high accuracy.

  Further, by providing the hook-shaped attachment portion, the hook can be hooked on a high potential portion such as a power transmission line, and voltage measurement can be performed. For this reason, there is also an effect that the voltage measurement is simplified.

(Configuration of the first embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. The high voltage measurement device according to this embodiment includes a light emitting unit 1, a detection unit 2, a sensor unit 3, and an attachment unit 5.

  The light emitting unit 1 includes a light source 11 and an input waveguide 12. The light source 1 is configured using an appropriate light emitting element that can emit coherent light. Examples of light-emitting elements that can be used include LD (laser diode) and LED (light-emitting diode). In this embodiment, a light source 1 that can emit light of two wavelengths (for example, 1300 nm and 1550 nm) is used. Such a light source can be configured by using a plurality of LDs or LEDs that emit light of each wavelength.

  In this embodiment, the input waveguide 12 is constituted by an optical fiber. The waveguide 12 is extended so that light (input light) emitted from the light source can enter a Pockels material 31 (described later) of the sensor unit 3. However, the waveguide 12 is not limited to an optical fiber, and may be configured to propagate in space using a mirror or a configuration using a waveguide, for example.

  With this configuration, the light emitting unit 1 is configured to irradiate the input light so that the light from the light emitting unit 1 passes through the first electrode 32 and the Pockels material 31 described later and reaches the second electrode 33. Yes.

  As shown in FIG. 2, the sensor unit 3 includes a Pockels material 31, a first electrode 32, a second electrode 33, a cylindrical body 34, an input lens 35, an input polarizer 36, and an output. A lens 37 and an output polarizer 38 are provided as main components.

The Pockels material 31 has a long columnar shape (for example, a columnar shape or a prismatic shape). The Pockels material 31 includes a first end 311 and a second end 312 (see FIG. 2). The Pockels material 31 is made of a substance having a Pockels effect. As a substance having the Pockels effect, for example, there is a Bi ₄ Ge ₃ O ₁₂ crystal (so-called BGO crystal).

  The first electrode 32 is attached in contact with the entire surface of the first end 311 of the Pockels material 31. The first electrode 32 is transparent to the input light from the light emitting unit 1. The first electrode 32 is electrically connected to a zero potential (ground) as a reference potential by a wiring 39. The reference potential is not necessarily a zero potential as long as there is no problem in measurement.

Examples of materials that can be used as the first electrode 32 include materials such as ITO, ZnO-based, SnO ₂ -based, In ₂ O ₃ -based, and conductive transparent polymer.

  The second electrode 33 is attached in contact with the entire surface of the second end 312 of the Pockels material 31. In the present embodiment, the second electrode 33 is also transparent to the input light from the light emitting unit 1. The material of the second electrode 33 may be the same as or different from that of the first electrode 32.

  The cylindrical body 34 is formed in a cylindrical shape, and the Pockels material 31 is stored inside the cylindrical body 34 (see FIG. 2). It is preferable that the cylinder 34 is comprised with the insulator.

  As shown in FIG. 2, the input lens 35 and the input polarizer 36 are disposed between the input waveguide 12 and the first electrode 32.

  The output lens 37 and the output polarizer 38 are disposed between the second electrode 33 and the output waveguide 22 (described later).

  The detection unit 2 includes a detection unit 21 and an output waveguide 22 (see FIG. 1). The output waveguide 22 is composed of an optical fiber, like the input waveguide 12. Of course, waveguides other than optical fibers may be used. The output waveguide 22 propagates light (output light) that has passed through the output lens 37 and the polarizer 38 to the detector 21 (see FIG. 2).

  The detection unit 21 is configured to measure a voltage applied between the first electrode 32 and the second electrode 33 based on a change in characteristics of the output light propagated through the waveguide 22. Specifically, the detection unit 21 detects a change in the polarization plane of the output light as a change in light intensity. The detailed operation principle will be described later.

  The attaching part 5 is attached to the upper outer surface of the cylindrical body 34 of the sensor part 3 (see FIG. 2). The attachment portion 5 is formed in a hook shape. Furthermore, the attachment part 5 is comprised with the electroconductive material, and has electroconductivity. As the conductive material, for example, an appropriate material such as a metal (for example, an aluminum alloy or a copper alloy) or a conductive resin can be used. However, it is preferable that the attachment portion 5 has sufficient rigidity to withstand the weight of the sensor portion 3 in a state where the attachment portion 5 is hooked on the measurement site. Further, the attachment portion 5 is electrically connected to the second electrode 33 by the wiring 40.

(Operation of the first embodiment)
Next, the operation of the high voltage measuring apparatus according to the first embodiment will be described. In the following example, the part to be measured as a voltage measurement target is the transmission line 6 shown in FIG.

  First, the sensor unit 3 is lifted and the hook-shaped attachment unit 5 is hooked on the power transmission line 6. This work can be easily performed by a worker wearing insulating gloves, for example. In this embodiment, unlike the prior art, no insulating gas is used. For this reason, the sensor part 3 becomes very lightweight, and an operator can easily lift it.

  By this operation, the sensor unit 3 is held in the air by the mounting unit 5 (see FIG. 1). In this state, a voltage from the power transmission line 6 is applied between the second electrode 33 and the first electrode 32 via the attachment portion 5. Although the first electrode 32 is grounded, since the Pockels material 31 is insulative, the second electrode 33 and the first electrode 32 will not be short-circuited.

  On the other hand, the input lens 35 is irradiated with input light from the light source 11 of the light emitting unit 1 through the input waveguide 12. At this time, in this embodiment, light of two wavelengths is irradiated from the light source 11 to the lens 35 as input light.

  The input light applied to the input lens 35 is collected by the lens 35 and then passes through the input polarizer 36. Thereby, the input light is linearly polarized.

  The input light that has passed through the polarizer 36 passes through the first electrode 32 and is irradiated onto the Pockels material 31. The input light applied to the Pockels material 31 causes a change in the plane of polarization corresponding to the applied voltage inside the Pockels material 31. The polarization plane is usually elliptically polarized. This is because if there is a potential gradient, a change in the refractive index corresponding to the direction of the gradient occurs.

  That is, if light is incident in the z direction, the light travels separately in the x-axis direction and the y-axis direction. At this time, the light propagation speed changes depending on the potential gradient between the light traveling along the x-axis and the light traveling along the y-axis. Then, in the light that has passed through the Pockels material 31, the plane of polarization fluctuates. Since the fluctuation of the polarization plane based on the Pockels effect itself is a known phenomenon, further detailed description is omitted.

  The light (output light) that has passed through the Pockels material 31 passes through the second electrode 33, is collected by the output lens 37, and passes through the polarizer 38. Since the polarizer 38 allows only the linearly polarized component to pass, the intensity of the light that has passed through the polarizer 38 becomes weaker corresponding to the polarization fluctuation caused by the Pockels material 31.

  The output light is propagated to the detector 21 via the output waveguide 22. The detector 21 calculates the voltage applied to the Pockels material 31 based on the detected light intensity. That is, the detector 21 detects a change in the polarization plane in the output light as a change in light intensity.

  In this embodiment, the first electrode 32 is transparent, and the input light is applied to the Pockels material 31 therefrom. Therefore, light can pass through a region sandwiched between the first electrode 32 and the second electrode 33 (that is, a region to which a voltage is applied).

  If light passes through a region adjacent to this region (indicated by a two-dot chain line in FIG. 3) instead of the region between the two electrodes as shown in FIG. There is a problem of deterioration. In FIG. 3, light is input from a hole formed in the center of the electrode.

  In the region between the electrodes, even if a disturbance electric field exists, the sum of the lines of electric force is constant between the electrodes. On the other hand, outside the region between the electrodes, the electric lines of force increase or decrease due to the proximity effect. For this reason, the accuracy of voltage measurement deteriorates. In contrast, in the present embodiment, the first and second electrodes 32 and 33 are transparent, and input light is transmitted from one electrode to the other electrode. For this reason, in this embodiment, the proximity effect does not occur in the voltage on the path through which the output light has passed, and the voltage can be accurately measured.

(Experimental example)
Next, experimental examples using the apparatus of the present embodiment will be described with reference to FIGS. First, the relationship between the applied voltage and the output light intensity in the Pockels material 31 is shown in FIG. In this figure, both characteristics at two wavelengths (1300 nm and 1500 nm) are shown. Thus, the output light intensity changes in a substantially sine curve shape as the applied voltage increases. This is because, as described above, the polarization state of the output light varies depending on the intensity of the applied voltage.

  Next, FIG. 5 and FIG. 6 show the relationship between time (horizontal axis) and output light intensity (vertical) at 80 kV AC and 250 kV AC. Based on the characteristics shown in FIG. 4, the amplitude in the waveform of the output light intensity varies depending on the wavelength of light. In the figure, “divider” is a measurement result obtained by a voltage divider.

  FIG. 7 shows a calibration curve for obtaining a voltage from the detected light intensity. First, an applied voltage (candidate value) corresponding to the light intensity at one wavelength is obtained. Next, an applied voltage (candidate value) corresponding to the light intensity at the other wavelength is obtained. The point where two candidate values overlap indicates the applied voltage. Although it is theoretically possible that the candidate values overlap at a plurality of points, the applied voltage in the target range can be measured by eliminating candidate values that exceed the assumed voltage range. The obtained voltage waveforms are shown in FIGS. This waveform had almost the same shape as the voltage at the voltage divider used as a reference.

  In the present embodiment, since lights of different wavelengths are input simultaneously, there is an advantage that the voltage can be accurately measured even when the voltage fluctuates.

  Of course, voltage measurement is possible even using light of one wavelength. However, in this case, it is necessary to narrow down the assumed voltage range. On the other hand, in this embodiment, since light of a plurality of wavelengths is used at the same time, there is an advantage that an applied voltage that can fluctuate in a very wide range can be accurately measured.

  In the above example, the applied voltage is an alternating current. However, according to the apparatus of the present embodiment, a voltage having an arbitrary waveform such as a direct current, an impulse shape, or a triangular wave shape can be measured.

  Further, in the above example, the output lens 37 is used. However, if a large-diameter optical fiber is used as the output waveguide 22, most of the output light is transferred to the output waveguide 22 without being condensed. It becomes possible to introduce. Therefore, with this configuration, the output lens 37 can be omitted, and the configuration of the apparatus can be further simplified.

(Second Embodiment)
Next, a high voltage measuring apparatus according to a second embodiment of the present invention will be described with reference to FIGS. In the description of this embodiment, the same reference numerals are used to simplify the description of the configuration that is basically common to the apparatus of the first embodiment.

  In this embodiment, the second electrode 33 (FIG. 11) is made of a material that reflects light from the light emitting unit 1. The material that reflects light is, for example, a conductive metal (such as aluminum or gold).

  In this embodiment, the branching portion 42 is disposed between the first electrode 32 and the input waveguide 12. The branching section 42 is configured to transmit the input light from the input waveguide 12. Further, the branching portion 42 reflects the light (output light) reflected and returned by the second electrode 33 so that the output light is incident on the output waveguide 22 disposed in the vicinity of the branching portion 42. It has become. With this configuration, the detection unit 2 is configured to measure the voltage based on light that has passed through the Pockels material 31 to reach the second electrode 33, is reflected by the second electrode 33, and has passed through the first electrode 32. It has become. Such a branch part 42 can be comprised by a half mirror, for example.

  In the apparatus of the second embodiment, the light irradiated from the input waveguide 12 passes through the branching section 42, the polarizer 36, and the lens 35 and is incident on the Pockels material 31. The plane of polarization of light traveling inside the Pockels material 31 varies according to the applied voltage. This is the same as in the first embodiment.

  The light that reaches the second electrode 33 is reflected by the second electrode 33 and returns to the first electrode 32. The output light transmitted again through the first electrode 32 is incident on the output waveguide 22 via the lens 35, the polarizer 36, and the branching unit 42. The subsequent operation is the same as in the first embodiment.

  According to the apparatus of the second embodiment, the input waveguide and the output waveguide can be collectively arranged on one end side of the sensor unit 3. For this reason, operations such as lifting the sensor unit 3 are facilitated. Since other configurations and advantages are the same as those of the first embodiment, detailed description thereof is omitted.

  In the second embodiment, the half mirror is exemplified as the branching unit 42. However, a polarizing beam splitter may be used as the branching unit 42. The polarizing beam splitter can serve as both a branching unit and a polarizer. Therefore, by using the polarization beam splitter, it is not necessary to separately provide the polarizer 36 and the branching portion 42, and one of them can be omitted. For this reason, the configuration of the apparatus can be further simplified.

  The light from the light emitting unit 1 can also be phase-modulated. In this case, the detector 21 of the detection unit 2 detects the light from the light emitting unit 1 out of the output light by synchronous detection. In this way, noise can be removed, so that the SN ratio of the voltage value obtained as an output can be improved.

  The high voltage measuring device of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

It is explanatory drawing which shows schematic structure of the high voltage measuring apparatus which concerns on 1st Embodiment of this invention. It is an expanded vertical sectional view which shows the structure of the sensor part in 1st Embodiment. It is an expanded vertical sectional view which shows roughly the structure of the sensor part shown as a comparative example. It is a graph which shows the relationship between an applied voltage and output light intensity. It is a graph which shows the fluctuation | variation of output light intensity in case an applied voltage is AC 80 kV, a vertical axis | shaft is output light intensity and a horizontal axis is time. It is a graph which shows the fluctuation | variation of output light intensity in case an applied voltage is AC 250 kV, a vertical axis | shaft is output light intensity and a horizontal axis is time. It is a graph which shows the calibration curve for calculating an applied voltage from output light intensity, a vertical axis | shaft is output light intensity and a horizontal axis is a voltage. It is a graph which shows the waveform of the voltage (AC 80 kV) measured by the experiment example. It is a graph which shows the waveform of the voltage (AC 250kV) measured by the experiment example. It is explanatory drawing which shows schematic structure of the high voltage measuring apparatus which concerns on 2nd Embodiment of this invention. It is an expanded longitudinal cross-sectional view which shows the structure of the sensor part in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emission part 11 Light source 12 Input waveguide 2 Detection part 21 Detector 22 Output waveguide 3 Sensor part 31 Pockels material 311 1st end part 312 2nd end part 32 1st electrode 33 2nd electrode 34 Cylindrical body 35 Input Lens 36 Input Polarizer 37 Output Lens 38 Output Polarizer 39 Grounding Wire 40 Wiring Between Mounting Portion and Pockels Material 42 Branch Portion 5 Mounting Portion 6 Transmission Line (Measurement Location)

Claims (10)

A light emitting unit, a detecting unit, and a sensor unit;
The sensor unit includes a Pockels material, a first electrode, and a second electrode.
The Pockels material has a first end and a second end;
The first electrode is attached in contact with the first end portion, and the first electrode is transparent to light from the light emitting portion,
The second electrode is attached in contact with the second end;
The light emitting unit is configured to irradiate the light so that light from the light emitting unit passes through the first electrode and the Pockels material and reaches the second electrode.
The detection unit measures a voltage applied between the first electrode and the second electrode based on a characteristic change of light that has passed through the Pockels material and reached the second electrode. ,
The light emitted from the light emitting unit includes light of a plurality of wavelengths,
The detection unit includes a point where a candidate value obtained corresponding to one wavelength in the light of the plurality of wavelengths and a candidate value obtained corresponding to the other wavelength overlap with the first electrode. The high voltage measuring device is configured to be specified as a voltage applied between the second electrode and the second electrode.   The high voltage measuring apparatus according to claim 1, wherein the change in the characteristic of the light is a change in a polarization plane of the light. It also has a mounting part,
The attachment part is attached to the sensor part,
The mounting portion is formed in a hook shape,
The mounting portion has conductivity,
Furthermore, the attachment portion is electrically connected to one of the first electrode or the second electrode,
The high voltage measuring apparatus according to claim 1, wherein the other of the first electrode and the second electrode is electrically connected to a reference potential.   The high-voltage measuring device according to claim 1, wherein the second electrode is transparent to light from the light emitting unit. The second electrode is a material that reflects light from the light emitting unit,
The detection unit is configured to measure the voltage based on light passing through the Pockels material and reaching the second electrode, and further reflected by the second electrode and passed through the first electrode. The high-voltage measuring device according to claim 1, wherein   6. The high electrode according to claim 1, wherein the first electrode and the second electrode are formed in contact with the entire surfaces of the first end and the second end. 7. Voltage measuring device.   The high-voltage measuring apparatus according to claim 1, wherein the Pockels material is formed in a column shape. The light from the light emitting part is phase modulated,
The high voltage measuring apparatus according to claim 1, wherein the detection unit is configured to detect light from the light emitting unit by synchronous detection.   The high-voltage measuring device according to claim 2, wherein the Pockels material is configured to be held in the air by attaching the attachment portion to a measurement site. A high voltage measuring method comprising the following steps:
(1) A step of applying a voltage between the first electrode and the second electrode respectively formed on the first end and the second end of the Pockels material;
(2) Before or after or simultaneously with the step (1), a plurality of the Pockels material are applied to the Pockels material in a portion where the voltage is applied and in a region sandwiched between the first electrode and the second electrode. Transmitting light including a wavelength of;
(3) Based on the point where the candidate value obtained corresponding to the light of one wavelength out of the light transmitted through the Pockels material and the candidate value obtained corresponding to the light of the other wavelength overlap. Measuring the applied voltage.

Images