CN106597053A - Straight optical path linear optical current sensor and current detection method - Google Patents

Abstract

The invention relates to a straight optical path linear optical current sensor and a current detection method. The sensor comprises a light source, a collimator, a polarizer, a first magnetic conduction plate, a magneto optical film, a second magnetic conduction plate and a radial polarization grating. The first magnetic conduction plate is arranged at one side of an air gapped ferromagnetic concentrator ring air gap opening, and the second magnetic conduction plate is arranged at the other side of the ferromagnetic concentrator ring air gap opening. The sensor also comprises a current-carrying wire which goes through a ferromagnetic concentrator ring. The detection method comprises the steps that: a light signal from the light source passes the collimator, the polarizer, the first magnetic conduction plate, the magneto optical film and the second magnetic conduction plate to reaches the radial polarization grating, a light spot with a fixed shaped is obtained by radial polarization, and through measuring the rotation angle of the light spot, the current value to be measured in the current-carrying wire is obtained. According to the device and the method of the invention, the reflection phase shift is eliminated, the measurement sensitivity is increased, the detection mode is independent of optical power, and the ranges and sensitivity of linear measurement and dynamic measurement are improved greatly.

Description

A kind of bar path linear optics current sensor and electric current detecting method

Technical field

The present invention relates to a kind of bar path linear optics current sensor and electric current detecting method.

Background technology

Optical current mutual inductor is broadly divided into full fiber type and the big class of mixed type two：The former passes light, sensing using optical fiber, The latter passes the magneto-optic memory techniques such as light optical fiber, sensing magneto-optical crystal, magneto-optic glass or magneto-optic thin film.Wherein mixed type optical current The sensing arrangement of transformer is mostly collection magnetic-type, and the optics such as prism, polarizer, magneto-optic memory technique are placed in iron core air gap, Therefore air gap is sufficiently large.But big air gap affects collection magnetic property, and makes sensing head volume bigger than normal.Entrance prism in light path with it is anti- Penetrate prism and introduce reflection phase shift, make line polarisation depolarization be oval thickness, reduce measurement sensitivity.At present biorthogonal reflection protect partially, Reflecting surface plated film is protected partially and the method for eliminating reflection phase shift such as inclined is protected in reflection at critical angle, and effect is undesirable, only protects inclined film reflection The measure error that phase shift causes just is up to 1.55%, requires far from the accuracy of measurement for meeting 0.2 grade of optical current mutual inductor. Additionally, the detection mode of optical current mutual inductor is all based on the polarised light light-intensity test pattern of Malus' law, measurement result With luminous power correlation, easily affected by optical power fluctuation；Using approximately linear conversion measurement during SIN function low-angle Faraday rotation angle, causes range of dynamic measurement and measures the limited in one's ability of harmonic wave.Meanwhile, what temperature drift and linear birefrigence were produced Random noise reduces the Stability and dependability of transformer longtime running, constrains its practical.

The content of the invention

It is an object of the invention to provide a kind of bar path linear optics current sensor and electric current detecting method, with gram Take defect present in prior art.

For achieving the above object, the technical scheme is that：A kind of bar path linear optics current sensor, bag Include：Be set in turn in light source in same light path, collimater, the polarizer, the first magnetic conductive board, magneto-optic thin film, the second magnetic conductive board with And radial direction analyzing grating；The side for being arranged at a ring concentrator air gap opening for opening air gap of first magnetic conductive board, described second The opposite side for being arranged at the ring concentrator air gap opening of magnetic conductive board；Also include a current carrying conductor for passing through the ring concentrator.

In an embodiment of the present invention, the ring concentrator air gap is less than 15mm, and Distribution of Magnetic Field is uniform.

In an embodiment of the present invention, first magnetic conductive board and second magnetic conductive board are square iron plate；It is described First magnetic conductive board and second magnetic conductive board correspondence offer the light hole of same size.

In an embodiment of the present invention, the radial direction analyzing grating is circle, and internal diameter is 4mm, and external diameter is 5mm；Grating grid Bar is aluminum metal, and spacing is 50nm.

Further, a kind of a kind of bar path linear optics current sensor based on described in claim 1 is also provided Electric current detecting method, optical signal obtains directional light from after light source collimater described in；The directional light is through described Device partially obtains linearly polarized light；After light hole of the linearly polarized light on first magnetic conductive board, the magneto-optic is injected into thin On film；The plane of polarization of linearly polarized light produces rotation in the presence of the current carrying conductor current field, produces an anglec of rotation；Line is inclined The light that shakes reaches the radial direction analyzing grating by the light hole on second magnetic conductive board, and a shape is obtained Jing after radial direction analyzing Fixed hot spot；The hot spot and the anglec of rotation synchronous rotary, by measuring the anglec of rotation of the hot spot load is obtained Current value to be measured in conductance line.

In an embodiment of the present invention, the size of the anglec of rotation is current field intensity, thang-kng length and magneto-optic thin film The linear function of Verdet constant.

In an embodiment of the present invention, the Jones matrix of the radial direction analyzing grating is：

Wherein, t_βRepresent the tangential amplitude of transmitted light, η represents the phase delay in transmitted light radially and tangentially direction, and β is light The anglec of rotation of grid.

Compared to prior art, the invention has the advantages that：The present invention is rectangular with light hole using two pieces Shape pure iron piece (magnetic conductive board) draws air-gap field, and magneto-optic thin film is placed in the middle of magnetic conductive board, and bar path does not need right angle reflection Prism, eliminates the impact of reflection phase shift.There was only the magneto-optic thin film of 400um thickness in air-gap field, greatly reduce line of tension Birefringent impact；Air gap is less than 15mm, and Distribution of Magnetic Field is obviously improved.And by radial direction analyzing grating, by Faraday rotation angle The synchronous axial system of ring-shaped light spot is converted to, directly carrying out signal transacting to light spot image can obtain current value to be measured, realize electricity The linear measurement of stream.

Description of the drawings

Fig. 1 is the structure chart of bar path linear optics current sensor in one embodiment of the invention.

Fig. 2 is the structural representation of radial direction analyzing grating in one embodiment of the invention.

Fig. 3 is the structural representation of grating in radial direction analyzing grating in one embodiment of the invention.

【Label declaration】：1- ring concentrators；2- current carrying conductors；The magnetic conductive boards of 3- first；The magnetic conductive boards of 4- second；5- light sources；6- is accurate Straight device；The 7- polarizers；8- magneto-optic thin films；9- radial direction analyzing gratings；10- light paths.

Specific embodiment

Below in conjunction with the accompanying drawings, technical scheme is specifically described.

The present invention provides a kind of bar path linear optics current sensor, as shown in figure 1, including：It is set in turn in same Light source 5, collimater 6, the polarizer 7, the first magnetic conductive board 3, magneto-optic thin film 8, the second magnetic conductive board 4 and radial direction analyzing in one light path Grating 9, to form a bar path；The side for being arranged at an air gap opening of ring concentrator 1 for opening air gap of the first magnetic conductive board 3, the The opposite side for being arranged at the air gap opening of ring concentrator 1 of two magnetic conductive boards 4；Also include a current carrying conductor 2 for passing through ring concentrator.

Further, in the present embodiment, ring concentrator air gap is less than 15mm, and Distribution of Magnetic Field is uniform.

Further, in the present embodiment, the first magnetic conductive board and the second magnetic conductive board are rectangular electrical pure iron piece； First magnetic conductive board and the second magnetic conductive board correspondence offer the light hole of same size.

Further, in the present embodiment, as shown in FIG. 2 and 3, radial direction analyzing grating is circle, and internal diameter is 4mm, External diameter is 5mm；Grating grizzly bar is aluminum metal, and spacing is 50nm.

Further, in the present embodiment, the bar path linear optics current sensor is based on bar path, farad What magnetic rotation luminous effect and radial direction analyzing method were realized.Optical signal obtains directional light from the collimator 6 of light source 5, then through being polarized Device 7 obtains linearly polarized light, is injected on magneto-optic thin film 8 by the light hole on the first magnetic conductive board 3, and the plane of polarization of polarised light is being carried Rotation is produced in the presence of conductance line current magnetic field, the size of the anglec of rotation is current field intensity, thang-kng length and magneto-optic thin film The linear function of Verdet constant, linearly polarized light reaches radial direction analyzer 9 by the light hole on the second magnetic conductive board 4, and Jing is radially The hot spot that a shape is fixed, hot spot and anglec of rotation synchronous rotary are obtained after analyzing, the anglec of rotation for measuring hot spot is obtained Current value to be measured.

Further, the Jones matrix of radial direction analyzing grating is：

Wherein, t_βRepresent the tangential amplitude of transmitted light, η represents the phase delay in transmitted light radially and tangentially direction, and β is light The anglec of rotation of grid.

In order to allow those skilled in the art to further appreciate that the device and detection method, enter with reference to specific embodiment Row explanation.

By taking 300A electric currents as an example, the operation wavelength of light source is 808nm, and spot diameter is 3mm, and the Fil moral of magneto-optic thin film is normal Number V is 1.5deg/cm.Oe.Preferably, the optimal size parameter of bar path sensing head is：Ring concentrator internal diameter 25mm, external diameter 35mm, high 25mm, superior distance is 14mm, the long 45mm of plate, wide 25mm between magnetic conductive board plate, and thickness is 5mm, the air gap thickness of ring concentrator For 10mm, the thickness of magneto-optic thin film is 400um.The bar path linear optics obtained using above-mentioned linear optics current sensor The ratio difference of current transformer is less than 0.0845%, and angular difference is less than 3.45 ', meets the requirement of 0.2S class of accuracies.

It is more than presently preferred embodiments of the present invention, all changes made according to technical solution of the present invention, produced function is made During with scope without departing from technical solution of the present invention, protection scope of the present invention is belonged to.

Claims (7)

1. a kind of bar path linear optics current sensor, it is characterised in that include：The light being set in turn in same light path Source, collimater, the polarizer, the first magnetic conductive board, magneto-optic thin film, the second magnetic conductive board and radial direction analyzing grating；First magnetic conduction The side for being arranged at a ring concentrator air gap opening for opening air gap of plate, ring concentrator air gap that is arranged at of second magnetic conductive board is opened The opposite side of mouth；Also include a current carrying conductor for passing through the ring concentrator.

2. a kind of bar path linear optics current sensor according to claim 1, it is characterised in that the ring concentrator Air gap is less than 15mm, and Distribution of Magnetic Field is uniform.

3. a kind of bar path linear optics current sensor according to claim 1, it is characterised in that described first leads Magnetic sheet and second magnetic conductive board are square iron plate；First magnetic conductive board and second magnetic conductive board correspondence are offered The light hole of same size.

4. a kind of bar path linear optics current sensor according to claim 1, it is characterised in that the radial direction inspection Polarisation grid are circle, and internal diameter is 4mm, and external diameter is 5mm；Grating grizzly bar is aluminum metal, and spacing is 50nm.

5. a kind of electric current detecting method of a kind of bar path linear optics current sensor based on described in claim 1, its It is characterised by, optical signal obtains directional light from after light source collimater described in；The directional light is obtained through the polarizer To linearly polarized light；After light hole of the linearly polarized light on first magnetic conductive board, it is injected on the magneto-optic thin film；Line The plane of polarization of polarised light produces rotation in the presence of the current carrying conductor current field, produces an anglec of rotation；Linearly polarized light leads to The light hole crossed on second magnetic conductive board reaches the radial direction analyzing grating, obtains what a shape was fixed Jing after radial direction analyzing Hot spot；The hot spot and the anglec of rotation synchronous rotary, by measuring the anglec of rotation of the hot spot current carrying conductor is obtained In current value to be measured.

6. the electric current detecting method of a kind of bar path linear optics current sensor according to claim 5, its feature It is that the size of the anglec of rotation is the linear function of current field intensity, thang-kng length and magneto-optic thin film Verdet constant.

7. the electric current detecting method of a kind of bar path linear optics current sensor according to claim 5, its feature It is that the Jones matrix of the radial direction analyzing grating is：

$GT=t_{\mathrm{\β}}\·e^{i\mathrm{\η}}\left(\begin{array}{cc}{\sin }^2\mathrm{\β}& -sin\mathrm{\β}cos\mathrm{\β}\\ -\sin \mathrm{\β}cos\mathrm{\β}& {\cos }^2\mathrm{\β}\end{array}\right)$

Wherein, t_βRepresent the tangential amplitude of transmitted light, η represents the phase delay in transmitted light radially and tangentially direction, β is grating The anglec of rotation.