JP2009244230A - Sensor fiber convolutional turning direction displaying technique - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus preventing mis-installation of convolutional turning direction of a sensor fiber in convolutional operation convolving a sensor fiber of a reflection-type fiber current measuring device around an measured object such as cables and the like. <P>SOLUTION: In order to implement convolutional turning of the sensor fiber 1 so as to conform a measuring direction of the sensor fiber 1 to a direction of the current flowing through the measured object, an indication 7 is installed, indicating a direction forced to agree with the flowing direction of measured current around periphery of the sensor fiber 1 turned conventionally around the measured object. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for indicating a measured current direction on a sensor fiber portion of a current measuring device using an optical fiber.

  As a device for measuring the current flowing through a conductor, the polarization plane of linearly polarized light propagating in an optical fiber is set to the magnitude of the measured current by the action of the magnetic field generated by the measured current flowing in the conductor to be measured. Using the principle of the Faraday effect that rotates proportionally, the current measurement device using an optical fiber (hereinafter referred to as “the optical fiber”) obtains the magnitude of the current by measuring the rotation angle of the polarization plane of the linearly polarized light incident on the sensor fiber. "Optical fiber current measuring device"). This optical fiber current measuring device is suitable for current measurement in high voltage equipment such as substation equipment and power transmission equipment because the sensor part is composed of optical components and has the advantage of not being affected by electromagnetic noise. ing.

  FIG. 5 shows the principle of the Faraday effect in which the plane of polarization of linearly polarized light passing through the sensor fiber rotates in proportion to the magnitude of the magnetic field. The plane of polarization of the linearly polarized light incident on the sensor fiber 1 rotates in proportion to the magnitude of the magnetic field H generated by the current to be measured in the sensor fiber 1. This rotation angle of the polarization plane is called Faraday rotation angle 10.

  In this optical fiber current measuring device, linearly polarized light is incident from one end of the sensor fiber, the light is reflected by a reflection mirror at the other end of the sensor fiber, and returned light (emits from the incident end of the sensor fiber). There is a reflection type optical fiber current measuring device capable of obtaining a current to be measured by measuring a rotation angle of a polarization plane of light. (Hereinafter referred to as “reflective optical fiber current measuring device”.)

  In addition, the reflection type optical fiber current measuring device has a feature that the current can be easily measured because the current of the object to be measured can be measured simply by winding the sensor fiber around the object to be measured. Especially when installing in existing equipment, it is not necessary to remove the existing cable or other wire that is the object to be measured in order to install the sensor fiber, it can be easily retrofitted and the measurement location can be changed easily. Are preferably used.

A configuration example of the reflection type optical fiber current measuring device is shown in FIG. The reflection type optical fiber measuring device includes a sensor fiber 1 (lead glass fiber), a light transmitting fiber 2, a light receiving fiber 3, a reflecting mirror 4, a sensor head including an optical system device 5, a light source 11, a light receiving element 12, and a signal processing circuit 6. It is comprised with the signal processing apparatus which consists of. In the reflection type optical fiber current measuring device shown in FIG. 6, the light emitted from the light source 11 passes through the light transmission fiber 2, is converted into linearly polarized light by the optical system device 5, and enters the sensor fiber 1. The incident linearly polarized light is reflected by the reflection mirror 4 at the other end of the sensor fiber and returns to the optical system device 5 again. The sensor fiber 1 is wound around the current to be measured, and the linearly polarized light is subjected to Faraday rotation due to the magnetic field H generated by the current to be measured when passing through the sensor fiber. The linearly polarized light extracted by the optical system device 5 passes through the light receiving fiber 3, is converted into an electric signal by the signal processing circuit 5, and the current to be measured can be obtained by measuring the Faraday rotation angle.

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  In order to install the reflection type optical fiber current measuring device in the actual equipment, it is necessary to wrap the sensor fiber around the object to be measured such as a cable. However, the conventional sensor fiber is wound around the object to be measured. When the sensor fiber installation worker installs the sensor fiber in the winding direction opposite to the preset winding direction, the phase of the measured current measured by the optical fiber current measuring device is There was a possibility that the measurement would be shifted by 180 degrees compared to the actual current.

  Here, it will be described that the phase of the current to be measured measured by the optical fiber current measuring device is shifted by 180 degrees compared to the actual current due to the difference in the winding direction of the sensor fiber.

  In FIG. 6, light emitted from the light source 11 is sent to the optical system device 5 through the light transmission fiber 2, converted into linearly polarized light, and incident on the sensor fiber 1. The linearly polarized light incident on the sensor fiber 1 is reflected by the reflection mirror 4 at the other end of the sensor fiber, passes through the sensor fiber 1 again, and is emitted from the sensor fiber 1. In the linearly polarized light that has passed through the sensor fiber 1, rotation of the polarization plane (Faraday rotation) proportional to the magnitude of the measured current I occurs due to the Faraday effect caused by the magnetic field H generated by the measured current I. Then, the rotation angle of the linearly polarized light is measured by a signal processing device, and the measured current I is obtained. In the state shown in FIG. 6, the sensor fiber 1 is wound in the clockwise direction F1 with respect to the measured current I, and the direction of the magnetic field H generated by the measured current I and the winding direction F1 of the sensor fiber are one. I'm doing it.

  On the other hand, FIG. 7 shows a state in which the sensor fiber 1 is wound in the counterclockwise direction F2 with respect to the current I to be measured. In this state, since the direction of the magnetic field H generated by the current I to be measured and the winding direction F2 of the sensor fiber do not match, the Faraday rotation received by the linearly polarized light passing through the sensor fiber is as shown in FIG. Compared to the reverse rotation, the direction of the measured current I measured by the optical fiber current measuring device is also reversed compared to the state of FIG. 6, and the phase of the measured current I is shifted by 180 degrees. It will be measured in the state.

When the winding direction of the sensor fiber around the object to be measured is reversed as described above, the phase of the current to be measured measured by the optical fiber current measuring device is measured by being shifted by 180 degrees compared to the predetermined current.

  Accordingly, in order to solve the above-described problem, the invention of claim 1 is a reflection type optical fiber current measuring device in which a display for instructing a predetermined winding direction is provided on a sensor fiber wound around an object to be measured. It is characterized by.

According to a second aspect of the present invention, in the reflection-type optical fiber current measuring device, the sensor fiber winding direction is displayed on the outer circumference of the sensor fiber by displaying a predetermined current direction of the object to be measured. The sensor fiber is wound around the object to be measured so that the direction of the display and the predetermined current direction of the object to be measured coincide with each other.

According to the present invention, in the work of wrapping the sensor fiber of the reflection type optical fiber current measuring device around the object to be measured such as a cable, the worker installing the sensor fiber has the direction of the current to be measured displayed on the sensor fiber. The sensor fiber can be installed in the specified winding direction by winding the sensor fiber around the measured object so that the display and the specified current direction flowing through the measured object match. Thus, it is possible to reliably prevent the phase of the measured current from being shifted by 180 degrees from the actual phase of the measured current.

  FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, the direction indication 7 of the current to be measured is indicated by arrows at two locations, that is, the storage portion of the reflection mirror 4 at the end of the sensor fiber and the storage portion of the optical system device 5. However, this display need only be able to confirm the direction in which the sensor fiber 1 is wound, so it does not necessarily have to be two places. Between the winding start portion of the sensor fiber 1 and the storage portion of the reflection mirror 4 at the end of the sensor fiber. There may be at least one place.

  FIG. 2 is a view showing a cross section of the sensor fiber. In FIG. 2, the direction indication 7 of the current to be measured is displayed at a plurality of locations in the same direction along the outer peripheral surface of the sensor fiber 1. If there are a plurality of such indications, the direction indicator 7 of the current to be measured can be installed in a state that can be reliably confirmed from the outside of the object to be measured even when the sensor fiber 1 is rotated, but at least if the winding direction of the sensor fiber can be confirmed. One place may be sufficient.

  Further, the direction display 7 of the current to be measured may take any form as long as there is no problem in practical weather resistance. For example, an arrow may be drawn directly on the covering portion of the sensor fiber, or the arrow may be displayed on a tape-like object and wound around the outer circumference of the object to be measured. Further, it may be displayed on a metal or plastic display tag and fixed to the outer periphery of the object to be measured.

  FIG. 3 is a view showing a state in which the sensor fiber 1 of the present invention is wound around the object 8 to be measured. FIG. 3 shows a state in which the sensor fiber 1 is wound around the device under test 8 so that the direction of the direction display 7 of the device under test and the direction of a predetermined current flowing through the device under test 8 coincide with each other. 1 is wound counterclockwise around the object 8 to be measured. In the winding state shown in FIG. 3, the winding direction of the sensor fiber coincides with the direction of the magnetic field H generated by the current I to be measured. This optical fiber current measuring apparatus defines this state as a predetermined current direction. ing.

FIG. 4 is a diagram showing a state in which the sensor fiber 1 is wound around the device under test 8 so that the direction of the direction display 7 of the current under test does not coincide with the predetermined current direction I of the device under test 8. In the wound state as shown in FIG. 4, the sensor fiber 1 is wound clockwise around the object to be measured, and the winding direction of the sensor fiber and the direction of the magnetic field H generated by the current I to be measured are shown in FIG. The direction of the current measured by the optical fiber current measuring device is in a state that is 180 degrees out of phase with the predetermined direction.

Configuration diagram showing an embodiment of the present invention The figure which shows the electric current direction display method of the Example of this invention. The figure which shows the installation method of the current direction display of the Example of this invention The figure which shows the incorrect installation method of the current direction display of the Example of this invention Diagram showing the principle of the Faraday effect The figure which shows the relationship between the winding method (clockwise) of the sensor fiber and the magnetic field generation direction by the Faraday effect in the reflection type optical fiber current measuring device The figure which shows the relation between the winding method (counterclockwise) of the sensor fiber and the magnetic field generation direction by the Faraday effect in the reflection type optical fiber current measuring device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sensor fiber 2 Transmitting fiber 3 Receiving fiber 4 Reflecting mirror 5 Optical system apparatus 6 Signal processing circuit 7 Direction indication of measured current 8 Measured object 9 Incident light (linearly polarized light)
10 Faraday rotation angle 11 Light source 12 Light receiving element F Sensor fiber winding direction F1 Sensor fiber winding direction (clockwise)
F2 Sensor fiber winding direction (counterclockwise)
I Current to be measured H Magnetic field generated by the current to be measured

Claims (2)

  In the reflection type optical fiber current measurement device, the sensor fiber winding of the reflection type optical fiber current measurement device is provided with an indication indicating a predetermined winding direction on the sensor fiber wound around the object to be measured. How to display the turning direction The indication indicating the winding direction of the sensor fiber displays a predetermined current direction of the object to be measured on the outer periphery of the sensor fiber, and the display direction of the current direction coincides with the predetermined current direction of the object to be measured. The sensor fiber winding direction display method of the reflective optical fiber current measuring device according to claim 1, wherein the sensor fiber is wound around the object to be measured.