CN201051119Y - Distributed optical voltage mutual inductor - Google Patents

Abstract

The utility model discloses a novel distributed optical voltage transformer used for measuring voltage of high voltage transmission lines by optical methods. An electro-insulated section of the distributed optical voltage transformer of the utility model is made from dielectric materials, the measured voltage is added on electrodes on the two ends of the utility model, the inner region of the electro-insulated section offers dielectric shielding of interference to disturb extraneous stray electric fields, a plurality of optical miniature electric-field sensors composed of electro-optical crystals Bi 4 Ge 3 O 12 and optical elements are arranged in the inner portion of the electro-insulated section in a longitudinal orientation to sense the electric-field in which the sensor is arranged, and the measured electric-field value is utilized as output signal and is transferred to data handling components via optical fibers, influence of various extraneous interferences is limited via a specific numerical integration method, thereby calculating the magnitude of voltage to be measured accurately.

Description

Distributed optical voltage transformer

Technical field

The utility model relates to a kind of novel optical voltage transformer, is used for particularly measuring the voltage of high voltage transmission line with optical method for measuring voltage.

Background technology

Measure accurately with optical means in recent years that the technology of voltage more and more arouses attention in the high voltage environment in power industry.With existing routine techniques, i.e. inductance or capacitance voltage transformer, or capacitance voltage voltage divider etc. compares, and the advantage that optical measuring technique has is:

The ability of-intrinsic anti-electromagnetic interference (EMI);

-no iron core saturation problem;

-excellent electrical insulation properties;

-bigger bandwidth;

-bigger dynamic range;

-light weight;

-very little volume;

-spread all over the precision of whole great dynamic range Nei Genggao;

-safe operating conditions

-low maintenance cost; Deng

Yet existing optical voltage transformer has utilized discrete optical element at large, and special electrode structure and seal, and needs to use insulating gas, as sulfur hexafluoride.This has caused structure significantly complicated; Cost obviously increases; Safeguard expensive difficulty; And sulfur hexafluoride is unfavorable to environmental protection; And the security that causes using reduces.

The utility model content

The purpose of this utility model is, a kind of distributed optical voltage transformer is proposed, be used for optical method for measuring voltage: it comprises that a component cloth is placed on the miniature optical electric-field sensor of its dielectric barrier electric insulation section, measure electric field value is removed to obtain voltage to be measured, particularly ultra-high-tension power transmission line again by the special value integration method voltage by described miniature optical electric-field sensor.It has high measurement accuracy, and can overcome the interference that various environmental factors cause.

Tested voltage can be alternating voltage, also can be DC voltage.

In order to realize the purpose of this utility model, a kind of distributed optical voltage transformer has been proposed, comprise the optical electric-field sensing unit, described optical electric-field sensing unit comprises light source, optical fiber, a plurality of miniature optical electric-field sensors and photodetector, described miniature optical electric-field sensor comprises electro-optic crystal; Dielectric barrier insulation unit; Described dielectric barrier insulation unit comprises the electric insulation section that is made of dielectric material and lays respectively at two conductor electrodes that electric insulation section two ends spacing distance is L that voltage to be measured is added on described two conductor electrodes; Data processing unit is used to receive the signal of optical electric-field sensing unit output, and calculates voltage to be measured; Wherein a plurality of miniature optical electric-field sensors are transformed into optical signalling with the electric field that voltage to be measured generates, and through described photodetector conversion input data processing unit, data processing unit utilizes specific integration method to calculate voltage to be measured; Electro-optic crystal optical axis in the wherein said miniature optical electric-field sensor is parallel with detection light beam and direction of an electric field to be measured, and promptly electro-optic crystal is in vertical orientation;

Consisting of of distributed optical voltage transformer of the present utility model: one group is used to measure its place, place electric field, and with measured value with light signal by Optical Fiber Transmission to the miniature optical electric-field sensor of data processing unit, as Fig. 1, shown in 10, the optical electric-field sensing unit of formation; An electric insulation segment unit that constitutes by dielectric material, as Fig. 1, shown in 12, it is that L lays respectively on the conductor electrode at its two ends that voltage V to be measured is added in spacing distance, as Fig. 1,13; Fig. 1, shown in 14, this insulating segment portion zone within it forms the dielectric barrier that stray electric field to external world etc. disturbs, and the miniature optical electric-field sensor places this insulating segment inside to remove to detect its place, place electric field; One is utilized the light signal of optical electric-field sensing unit output to remove to make up the data processing unit of calculating voltage exact value V to be measured by the special value integration method, as Fig. 1, shown in 11.These three unit interosculate and have formed: distributed optical voltage transformer.

Optical electric field sensor

The utility model is a kind of miniature optical electric-field sensor based on linear electro-optic effect (Pockels electro-optic effect).

Miniature optical electric-field sensor (Pockels cell) is the core devices of distributed optical voltage transformer system, it can well be resisted because of ambient temperature and the intensity of light source change the influence that produces and remove to measure electric field with the precision that satisfies the IEC standard, and has big dynamic range, high bandwidth, good runnability also satisfies long-time stability and reliability requirement simultaneously.

All optical electric field sensors are generally less than 2% along the length summation of direction of an electric field and the ratio of two electrode separation L in the optical voltage transformer system, so institute's measured value is approximately an electric field value, so that the optical voltage transformer system obtains enough precision.So these used optical element dimension are all very little, are called the miniature optical electric-field sensor.Abbreviate as: micro field sensor.

Bi ₄Ge ₃O ₁₂Crystal is called for short the BGO crystal, has cubic symmetry point group 43m, and also note is done: T _dIts three non-vanishing matrix elements equate: r ₄₁=r ₅₂=r ₆₃. the orientation that the BGO crystal is got in the miniature optical electric-field sensor, the extra electric field direction, and the pass between the direction of beam propagation three is:

BGO crystal in the micro field sensor is got vertical orientation in optical voltage transformer, as Fig. 6 a, shown in the b, that is: the optical axis direction of BGO crystal detects the direction of light beam in the crystal, extra electric field, the direction of electric field to be measured just, this three is parallel mutually, promptly all is in same direction, as Fig. 6, shown in 41.Usually the optical axis of getting the length direction of BGO crystalline size is as the direction of beam propagation and the direction of electric field to be measured, and to get this direction be z direction of principal axis in the rectangular coordinate system, as Fig. 1, and 10; Fig. 6 a is shown in the b.

By extra electric field, what just electric field to be measured was inducted propagates the poor of optical index between two quadrature optics polarization modes of light beam along the z axle, i.e. linear birefrigence is:

$\mathrm{\Δn}=n_0^3{r}_{41}{E}_z---\left(1\right)$

Phase differential is between two quadrature optics of Dui Ying this polarization mode with it:

$\mathrm{\δ}=\frac{2\mathrm{\π}{n}_0^3{r}_{41}{V}_z}{{\mathrm{\λ}}_0}---\left(2\right)$

Wherein:

n ₀Be not subjected to the BGO crystal refractive index of external electric field disturbance;

r ₄₁BGO crystal electrooptical coefficient;

V _zThe BGO electro-optic crystal is at two suffered impressed voltages of end face of z direction of principal axis;

V _z＝E _z·L _z

λ ₀Used light source wavelength in a vacuum;

L _zThe BGO electro-optic crystal detects beam direction, the just length of direction of an electric field to be measured at the z direction of principal axis;

E _zThe longitudinally outer electric field that is added on the BGO crystal, electric field promptly to be measured

When optical electric field sensor is placed in vertical orientation, be that unique depending on is added to the electric field on the BGO crystal then along the linear birefrigence of being inducted between two quadrature optics polarization modes of z axle propagation.

The sensitivity of electro-optic crystal is only by three factor decision: λ when optical electric field sensor is in vertical orientation ₀n ₀r _Ij, be r herein ₄₁, and irrelevant with the length and the physical dimension of used BGO crystal.This can promptly be produced the pairing voltage of π phase differential and be represented by half-wave voltage:

$V_{\mathrm{\π}}=\frac{{\mathrm{\λ}}_0}{2n_0^3{r}_{41}}---\left(3\right)$

Vertical optical electric field sensor of setovering,, transmissivity T is as shown in Figure 3:

$T=\frac{1}{2}[1+\sin \left(\mathrm{\π}\frac{V}{V_{\mathrm{\π}}}\right)]---\left(4\right)$

Work as relation:

V＜＜V _π (5)

When the restrictive condition of expression satisfies, then have following approximation relation to set up:

$T\≈\frac{1}{2}(1+\mathrm{\π}\frac{V}{V_{\mathrm{\π}}})---\left(6\right)$

So,, embody and be biased the external alive response in back the enough good linearity is arranged as long as condition (5) satisfies the fine approximate of transmissivity that following formula is exactly the longitudinal biasing micro field sensor and impressed voltage relation.

And from (4) formula as seen, as long as condition (5) satisfies and add the variation that a little electric field will cause the transmissivity maximum on this electric-field sensor.This just shows and is biased back electric-field sensor sensitivity maximum.

In the optical voltage transformer system construction, because the BGO crystal of micro field sensor is along the z shaft length, promptly in the dimension of direction of an electric field, much smaller than the distance L between the two high-tension electricity utmost points, voltage suffered on the BGO crystal is much smaller than its half-wave voltage V _πSo condition (5) always can satisfy.Therefore, BGO crystal optics micro field sensor can have appropriate sensitivity, the very high linearity, and sufficiently high precision, and corresponding sizable range of dynamic measurement.

Miniature optical electric field sensing of the present utility model unit can utilize Fig. 4 (a, b, c, d, e) in any among each form optical electric-field sensing unit of signal, can both obtain two light intensity signal S that complement each other at its signal output part ₁And S ₂Can be translated into the output valve of digital electronic signal: a by photo-detector and analog to digital converter, b, and then calculate this miniature optical electric-field sensor by data processing unit according to following method and surveyed the electric field exact value.

When tested voltage is DC voltage, then should utilize the miniature optical alternating current-direct current electric field sensing unit of illustrating among Fig. 5, and then ask the DC electric field method to remove to calculate this miniature optical electric-field sensor to be surveyed the DC electric field exact value according to following by data processing unit, referring to formula 17.

The distributed optical voltage transformer of the utility model, as Fig. 1, shown in Figure 2, comprise an electric insulation segment unit that constitutes by dielectric material, as Fig. 1, shown in 12, it is L and being in respectively on the conductor electrode at its two ends that tested voltage is added in by spacing distance, one of them electrode connects the high voltage transmission line current potential, as Fig. 1, shown in 13, another earthing potential, as Fig. 1, shown in 14; This insulating segment has selected specific inductive capacity and special composition, structure and shape, normal is tubular column, resistor-type dielectric barrier pipe with the electrode linking, be placed in above-mentioned hollow insulation tube inside, the cavities zone forms the dielectric barrier that stray electric field to external world etc. disturbs within it thus, as shown in Figure 2.N miniature optical electric-field sensor places this insulating segment interior zone axis to get on and detects the electric field that its place is located; So just reduced the error that interference such as extraneous stray electric field cause.

In distributed optical voltage transformer of the present utility model: utilize the insulating material and the structure that are easy to obtain, it is general column support type insulated column, cooperation is with several miniature optical electric-field sensors that are placed in its inner ad-hoc location, add the transmission of light signal and survey disposal system etc., just can construct distributed optical voltage transformer.

The dielectric barrier insulation unit of distributed optical voltage transformer of the present utility model comprises:

As Fig. 1, shown in Figure 2, by the insulating segment that metal support supports, can be hollow circular tube shape compound substance insulated column.Be mainly used in the mechanical support of miniature optical electric-field sensor and prevent interference and the destruction of various spuious external conditions the miniature optical electric-field sensor.

With high-field electrode and the ground-electrode that quite big separating distance is opened, be built in hollow circular tube shape compound substance insulating segment two ends.

Provide the hollow circular tube shape resistor of dielectric barrier to be installed in insulating segment inside, between two electrodes at insulating segment two ends, top electrodes and transmission line high-pressure side are done electric connection, and bottom electrode is then got earth potential.To the zone between two electrodes, utilize the material of high dielectric constant to form dielectric barrier, the various mixed and disorderly electric field interference source from the outside is carried out dielectric barrier.

-hollow circular tube shape compound substance insulating segment in-discard with sulfur hexafluoride gas, or oil, paper waits material to make the demand of special insulation.

Several miniature optical electric-field sensors of being made by dielectric material are placed on the resistance shielded-plate tube axis line inside in the tubular compound inslation section.Determine the position coordinates of each micro field sensor on the axis according to numerical integration algorithm, the orientation orientation is installed then as Fig. 1, Fig. 2 and Fig. 6 a are shown in the b.The micro field sensor of Zhi Fanging is used for accurately measuring its loca electric field in this way.

The light of light source is sent into by optical fiber and is attached thereto the micro field sensor that connects, and the light detection device that the light signal of exporting is sent in the pulpit is converted to electric signal again, finally provides the magnitude of voltage that will survey by data processing unit then.

The basic comprising of distributed optical voltage transformer of the present utility model: from top to bottom, referring to Fig. 1, Fig. 2

^*The top conductor electrode that links to each other with high voltage transmission line; Have grading ring;

^*With the hollow insulation pipe of composite dielectric materials such as glass fibre as tube wall, the insulating material full skirt is equipped with in the outside, constitutes insulation column;

^*With the resistor-type dielectric barrier pipe that the insulating segment two end electrodes is connected, be placed in above-mentioned hollow insulation pipe inside;

^*The ground-electrode base plate that conductor constitutes; With the grounded bracket that constitutes with conductor.

^*The miniature optical electric-field sensor is placed in respectively on the axis of insulation tube, and its position is provided by numerical integration algorithm.

^*The miniature optical electric-field sensor is placed in respectively on the axis of insulation tube, and its orientation orientation is by Fig. 6 .a, and Fig. 6 .b provides.

^*Optical fiber is connected in light source, and light is imported into micro field sensor, and its light signal of exporting is transferred back to photo-detector and the data processing unit that is positioned at the pulpit, is used to calculate the voltage of obtaining on the hv transmission line.

The advantage of the utility model optical voltage transformer is:

-without any need for relying on client's condition electrode structure customized with and/or the special insulation device;

-do not need the sulfur hexafluoride gas-insulating that pressurizes, do not need oil-paper yet, wait material as insulation, reduced manufacturing cost and maintenance cost thus, reduced the risk of environmental pollution;

-because high voltage part and earth potential part by the separating of broad, so just can satisfy insulation requirements in the middle of the insulated column that dry nitrogen or air are filled in hollow, make the electric insulation security increase of this distributed optical voltage transformer.

-owing to regulate the measuring accuracy that the number of miniature optical electric-field sensor just can increase voltage to be measured, make the precision of this optical voltage transformer be easy to improve.

Description of drawings

Figure .1 is distributed optical voltage transformer basic structure synoptic diagram;

Figure .2 is distributed optical voltage transformer system global structure synoptic diagram;

Fig. 3 is the vertical optical electric field sensor principle schematic of biasing;

Fig. 4 .a is the optical electric-field sensing unit of first embodiment of optical voltage transformer of the present utility model;

Fig. 4 .b is the optical electric-field sensing unit of second embodiment of optical voltage transformer of the present utility model;

Fig. 4 .c is the optical electric-field sensing unit of the 3rd embodiment of optical voltage transformer of the present utility model;

Fig. 4 .d is the optical electric-field sensing unit of the 4th embodiment of optical voltage transformer of the present utility model;

Fig. 4 .e is the optical electric-field sensing unit of the 5th embodiment of optical voltage transformer of the present utility model;

Fig. 5 is the optical electric-field sensing unit of the 6th embodiment of optical voltage transformer of the present utility model;

Fig. 6 .a is the structure of miniature optical electric-field sensor of the present utility model and places the orientation synoptic diagram;

Fig. 6 .b is the another kind of structure of miniature optical electric-field sensor of the present utility model and places the orientation synoptic diagram.

The number in the figure explanation:

10. miniature optical electric-field sensor

11. data processing unit

12. the electric insulation section that dielectric material constitutes

13. the top conductor electrode that links to each other with high voltage transmission line

14. ground-electrode

15. hollow insulation pipe

16. resistor-type dielectric barrier pipe

17. grading ring

18. insulation cluster parachute

19. conductor support

20. the top conductor that links to each other with high voltage transmission line

21. ground

24. incident detects light beam

25. optical polariser

26. optics quarter wave plate

27. optics analyzer

28. light source

29. optical fiber

30. polarizing beam splitter

31.32.33. optical alignment coupling mechanism group

34. photo-detector

35. the online polarizer of optical fiber

36. the online quarter wave plate of optical fiber

37. polarization maintaining optical fibre

38. optical prism

39. unpolarized optical splitter

40. birefringent phase modulator

41.BGO electro-optic crystal

Embodiment

Below in conjunction with accompanying drawing, introduce the embodiment of optical voltage transformer of the present utility model in detail

First embodiment

A). to be measured is alternating electric field

Described optical electric-field sensing unit is at least by the optical fiber that is in the high voltage environment, optical polariser, optical alignment coupling mechanism, optics quarter-wave plate, electro-optic crystal Bi ₄Ge ₃O ₁₂(brief note is: BGO), and the formed miniature optical electric-field sensor of polarizing beam splitter, and be in the outer light source of high voltage environment, optical fiber and photodetector constitute; Shown in Fig. 4 a.

The light that light source sends is by Optical Fiber Transmission, send optical polariser to through optical alignment coupling mechanism group, both order are commutative, again by entering behind the optics quarter-wave plate among the electro-optic crystal BGO, wave plate and crystal order are also commutative, be proportional to the phase differential that is added to electric field to be measured on the BGO because of linear electro-optic effect produces between two cross polarization light components, polarizing beam splitter separates with the optical alignment coupling mechanism and calculate voltage exact value V to be measured by data processing unit after optical fiber passes to these two cross polarization light components corresponding photodetector to be converted to electric signal separately

Utilize the one-piece construction of the miniature optical electric-field sensor of illustrating among Fig. 4 a, can obtain two light intensity signal S that complement each other at its signal output part ₁And S ₂, can be translated into the output valve of digital electronic signal by photo-detector and analog to digital converter: a, b.And then remove to calculate this miniature optical electric-field sensor by data processing unit according to following method and surveyed the electric field exact value.

The miniature optical electric-field sensor need utilize two to complement each other, by photo-detector and analog to digital converter with light intensity signal S ₁And S ₂Be converted into the output valve of digital electronic signal: a, b.Count the loss in transmission and the conversion process, and after the influence of scale factor variation, numerical value a represents corresponding light intensity S ₁, that is:

a＝K _a*S ₁； (7-a)

Equally: b=K _b* S ₂(7-b)

In data processing unit, utilize the value of a and b can calculate the electric field of measuring by micro field sensor.

From establish an equation down, can obtain the transport function of micro field sensor:

With

Wherein:

P ₀Enter total light intensity of micro field sensor;

E added electric field intensity on the optical propagation direction electro-optic crystal, or the average field intensity on the micro field sensor entire length;

E _πSet up the needed electric field intensity of π phasic difference in the electro-optic crystal between the polarization propagating mode of two quadratures;

Biasing or initial phase difference on the electro-optic crystal between the polarization propagating mode of two quadratures, mainly by wave plate control, typical case is got pi/2;

α shows the coefficient of imperfection degree in the micro field sensor making;

K _a, K _b: for signal a and b, the power loss factor separately;

More than two formulas can be rewritten as:

With

Wherein

Be phase bias residual in the micro field sensor, mainly stem from the imperfection of used wave plate, can come also that wave plate since then produces because of ambient temperature changes with respect to

Depart from.

When the major part of tested electric field or voltage is under the situation of 50Hz AC signal

E＝E ₀sinωt (11)

Wherein

E ₀The alternating electric field amplitude;

Alternating electric field angular frequency: ω=2 π f, f: frequency (50Hz); T: time;

In order accurately to measure electric field, must cancel, minimize or compensate because of light source intensity, a that interference such as temperature variation or vibration cause, the variation of each parameter in b and the transport function.This can utilize (9-a, 9-b) formula is calculated the standardization transport function:

Wherein $K=\frac{K_a}{K_b}---\left(13\right)$

From (12,13) formula, can solve the extra electric field on the micro field sensor of being asked:

If α,

E _πAll known with K, the value of electric field E then to be measured can utilize following formula to obtain from the value of measured signal a and b by data processing unit.For each micro field sensor, α and E _πCan determine by test, can draw by demarcation.K then depends on the loss of light path and electronic circuit in the signal path, can change to some extent in time, so system's reply it constantly follow the tracks of monitoring dynamically.The phase bias that micro field sensor is residual

Also should be monitored frequently.

When tested amount mainly is by the represented sinusoidal alternating signal of (11) formula, then the K value can be used (9), and (11) two formulas are obtained: measure the absolute value of the alternating compenent of signal a and b respectively, just can obtain the K value from following formula:

$K=\frac{\left|a_{\mathrm{AC}}\right|}{\left|b_{\mathrm{AC}}\right|}=\frac{K_a}{K_b}$

Residual subsequently phase bias

Can try to achieve with (10) and (14) formula:

Following formula is zero to the mean value of time, so have:

Because K and

Any variation of value can both be followed the tracks of by optical voltage transformer system dynamics ground, monitoring and regulate and be measured accurately, and this just makes with (14), when (15) formula is calculated electric field since due to the various interference K and

Any variation of value can not cause influential error to the survey magnitude of voltage.

The electric field value that utilizes the output of miniature optical electric-field sensor and obtain by this signal processing method, can in hyperbaric environment, spread all over quite wide temperature range and exist the intensity of light source to change and during various interferences such as vibration, place, miniature optical electric-field sensor place electric field is carried out reliable and accurate measurement.

By the above electric field value that obtains, can obtain magnitude of voltage to be measured through following Gauss's numerical integration method calculating.

A, b, the voltage of point-to-point transmission can go out from the point-to-point transmission electric Field Calculation:

$V_{\mathrm{ba}}=-{\∫}_{{\mathrm{\Γ}}_{\mathrm{ab}}}\stackrel{\→}{E}\·\stackrel{\→}{d}l---\left(1\right)$

Here Γ _AbIt is the free routing from a to b in the space.

Utilize cartesian coordinate system, get path Γ _AbAlong shortest path is straight line, and then following formula can be written as:

$V_{\mathrm{ba}}=-{\∫}_a^b{E}_z\left(z\right)\mathrm{dz}---\left(2\right)$

A wherein, b is getting E on the z axle _z(z) being at the component of z point place electric field along the z axle, is the function of coordinate z.

Voltage can utilize limited electric field sampling value to come that line integral (2) is done limited weighted sum and be similar to:

$V=-{\∫}_a^b{E}_z\left(z\right)\mathrm{dz}=-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\α}}_i{E}_z\left(z_i\right)---\left(3\right)$

Here:

E _z(z _i) on axis between the insulating segment two end electrodes, i.e. z on the z axle _iPut the component of the electric field at place along the z axle,

α _iz _iThe electric field value E that some place micro field sensor is measured _z(z _i) pairing weight,

z _iMicro field sensor on axis between the insulating segment two end electrodes, i.e. position coordinates on the z axle,

N is to axis between two electrodes of insulating segment, the i.e. sampling number of electric field value, just micro field sensor number on the z axle;

For n miniature optical electric-field sensor, there be 2n known variables: a n location variable, and n weight variable.Ideally, the selected variation sum that should make extraneous all kinds of interference cause of these variablees is minimum.

Here initial point is to be taken at a point place, as shown in Figure 1.

Be defined as by perturbed system that an any system without disturbance is disturbed and system after changing.

The example of these variations comprises: near the appearance of other voltage sources of space; And dielectric medium becomes inhomogeneous etc.So just produce by the electric field E after the disturbance ^p(z), it along z axle component is for x, y

$E_z^p(\mathrm{0,0},z)=E_z^p\left(z\right)$

E _z ^p(z) can use E _z ^Up(z) item is expressed:

$E_z^p\left(z\right)=E_z^{\mathrm{up}}\left(z\right)\mathrm{\ρ}\left(z\right)---\left(4\right)$

The ρ here (z) is when optical voltage transformer system pairing variable quantity when never state of disturbance enters by state of disturbance.This algorithm requires E _z ^Up(z) being known quantity, preferably is exactly the E that is undisturbed in the system _z(z).In actual conditions, be easy to draw E by setting up electric field model by means of numerical method _z ^Up(z).

Generation (4) go into (3) and the right changed after:

$V=-{\∫}_a^b{E}_z^{\mathrm{up}}\left(z\right)\mathrm{\ρ}\left(z\right)\mathrm{dz}=-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{w}_i\mathrm{\ρ}\left(z_i\right)---\left(5\right)$

The integration is here expressed with the variable quantity ρ (z) at n some place on the z axle, wherein:

$w_i={\mathrm{\α}}_i{E}_z^{\mathrm{up}}\left(z_i\right)---\left(6\right)$

Exist a simple method and remove to obtain w in (5) formula _iAnd z _i, Here it is Gauss's numerical integration algorithm.

Getting ρ (z) is the ascending power polynomial expression, and allows (5) formula accurately set up.

Here sampling spot position coordinates z _iWeight w with respective point _iBe two unknown quantitys that need be determined.

Here m _kBe k rank square, it is the given integration of following formula, has relation:

ρ (z)=z ^k, be 1, z, z ², z ³... z ^2n-1:

$m_k=-{\∫}_a^b{E}_z^{\mathrm{up}}\left(z\right)z^k\mathrm{dz}---\left(7\right)$

Suppose that ρ (z) can be well approximate by a n rank polynomial expression, get ρ (z), then provide 2n equation for not being higher than the ascending power polynomial expression on 2n-1 rank:

m ₀＝w ₁+w ₂+w ₃...+w _n

m ₁＝w ₁z ₁+w ₂z ₂+w ₃z ₃...+w _nz _n

$m_2=w_1{z}_1^2+w_2{z}_2^2+w_3{z}_3^2...+w_n{z}_n^2$

$m_{2n-1}=w_1{z}_1^{2n-1}+w_2{z}_2^{2n-1}+w_3{z}_3^{2n-1}...+w_n{z}_n^{2n-1}---\left(8\right)$

Separate the method for this Nonlinear System of Equations:

The defined feature polynomial expression:

$\mathrm{\π}\left(z\right)=\underset{i=1}{\overset{n}{\mathrm{\Π}}}(z-z_i)=\underset{k=0}{\overset{n}{\mathrm{\Σ}}}{C}_k{z}^k---\left(9\right)$

Annotate: π (z _iIf)=0 is i=1, and 2 ... n

Here z _iBe exactly the zero point of proper polynomial π (z), and C _kIt is this polynomial coefficient.

To the both sides of each equation from top to bottom in the system of equations (8) of top, first equation be multiply by C ₀, second equation multiply by C ₁... n equation multiply by C _n

Get C _n=1; Then all equation addition summations in (8) formula are got:

$\underset{k=0}{\overset{n}{\mathrm{\Σ}}}{C}_k{m}_k=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{w}_i\mathrm{\π}\left(z_i\right)=0---\left(10\right)$

Subsequently various each coefficient in (8) is moved down, allow next equation both sides with taking advantage of each coefficient.

And then repeat this summation process:

$\underset{k=0}{\overset{n}{\mathrm{\Σ}}}{C}_k{m}_{k+1}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{w}_i{z}_i\mathrm{\π}\left(z_i\right)=0$

This process should repeat n time, up to obtaining the system of linear equations that n equation constitutes:

$\underset{k=0}{\overset{n}{\mathrm{\Σ}}}{C}_k{m}_{k+l}=0$ l＝0，1，2，...n-1； (11)

If: | m _K+l| ≠ 0

Then utilize C _n=1, can solve all C _kValue.

Each m wherein _kCan obtain from (7) formula.So each C in the following formula _kValue can all solve.

Since whole coefficient C _kValue knows that all then this proper polynomial (9) is just determined by unique, and can obtain its each zero point, so its root just can solve.Here it is the micro field sensor coordinate figure z on insulation tubing string axis _i, the position of electric field to be measured sampling place just.

Work as z _iValue all obtained after since independently only contain n unknown number w in the equation at this n _i, i=1,2 ... n, utilize preceding n the equation of (8) formula just can try to achieve the weight w of each electric field sampling value correspondence _i

Can calculate z from (6) formula _iThe electric field value E that some place micro field sensor is measured _z(z _i) directly corresponding weight:

${\mathrm{\α}}_i=\frac{w_i}{E_z^{\mathrm{up}}\left(z_i\right)}$

Try to achieve z _iAnd α _iAfter, because always can not to be higher than any polynomial expression on 2n-1 rank by an exponent number enough accurately approximate for the factor ρ (z) of the actual extraneous all kinds of interference of the expression of definition (4), so (3) degree of accuracy of integral algorithm is just can be enough high in the formula, the electric field value that just can utilize a plurality of miniature optical electric-field sensors to measure is done weighted sum and is obtained the exact value of voltage V to be measured.

Second embodiment, shown in Fig. 4 b, to compare with first embodiment shown in Fig. 4 a, optical polariser among second embodiment and optics quarter-wave plate are made of the online device of optical fiber, the structure of the second embodiment remainder, and specific implementation process is identical with first embodiment.

The 3rd embodiment. shown in Fig. 4 c, compare with first embodiment shown in Fig. 4 a, optical polariser among the 3rd embodiment and optics quarter-wave plate are made of the online device of optical fiber, and the polarizer is outside high voltage environment, the structure of the 3rd embodiment remainder, and specific implementation process is identical with first embodiment.

The 4th embodiment. shown in Fig. 4 d, compare with first embodiment shown in Fig. 4 a, the linearly polarized light that is provided by optical polariser among the 4th embodiment passes through electro-optic crystal earlier, be converted to rotatory polarization by wave plate again, the structure of the 4th embodiment remainder, and specific implementation process is identical with first embodiment.

The 5th embodiment. shown in Fig. 4 e, compare with first embodiment shown in Fig. 4 a, the characteristics of the 5th embodiment are that the light path in the electro-optic crystal is reflective: the linear polarization incident beam that optical polariser provides among the 5th embodiment is by behind the electro-optic crystal, through being in the optical prism of electro-optic crystal one end, or pass through electro-optic crystal again behind the prismatic reflection that constitutes with the other end of electro-optic crystal, enter the optics quarter-wave plate, the structure of the 5th embodiment remainder, and specific implementation process is identical with first embodiment.

Among the first five embodiment, described optics quarter-wave plate is positioned at electro-optic crystal incident end, yet this optics quarter-wave plate also can be positioned at the electro-optic crystal exit end, can obtain identical effect.

The 6th embodiment. miniature optical alterating and direct current pressure sensor

B). to be measured is DC electric field

Described optical electric-field sensing unit is at least by the polarization maintaining optical fibre or the general single mode fiber that are in the high voltage environment, optical alignment coupling mechanism, optical polariser, electro-optic crystal Bi ₄Ge ₃O ₁₂(brief note is: BGO), unpolarized optical splitter, optics quarter-wave plate group, the formed miniature optical electric-field sensor of optics analyzer group, and be in light source in the pulpit, polarization maintaining optical fibre or general single mode fiber, birefringent phase modulator, the photodetector group, signal generator is in conjunction with formation;

The light that light source sends by the alternating voltage that provides with signal generator by in the birefringent phase modulator periodic variation optical fiber after the polarization state of light of propagating realizes phase modulation (PM), send optical polariser through Optical Fiber Transmission to optical alignment coupling mechanism group, both order of back are commutative, become polarized light and enter electro-optic crystal BGO and optics quarter-wave plate, because of producing, linear electro-optic effect is proportional to the phase differential that is added to electric field to be measured on the BGO between two cross polarization light components, unpolarized optical splitter and optics analyzer group and optical alignment coupling mechanism component from and after optical fiber passes to corresponding photodetector separately with these two cross polarization light components and is converted to electric signal, calculate voltage exact value V to be measured by data processing unit; The optical electric field sensor of Gou Chenging can be used for the measurement of DC electric field in this manner, also can be used for the measurement of AC field.As shown in Figure 5.

For a DC electric field E to be measured, can calculate from the output signal of miniature optical combined-voltage sensor groups:

$E=\frac{E_{\mathrm{\π}}}{2\mathrm{\π}}\left\{{\mathrm{ctg}}^{-1}\right[\frac{\left|a_{m1H}\right|}{\left|a_{m2H}\right|}\frac{J_2\left({\mathrm{\φ}}_m\right)}{J_1\left({\mathrm{\φ}}_m\right)}]+{\mathrm{ctg}}^{-1}[\frac{\left|a_{m1H}\right|}{\left|a_{m2H}\right|}\frac{J_2\left({\mathrm{\φ}}_m\right)}{J_1\left({\mathrm{\φ}}_m\right)}\left]\right\}---\left(17\right)$

Wherein

E _πBe the half-wave electric field of the half-wave voltage correspondence of BGO crystal.

φ _mSin ω _mT provides and is added in the phase modulation (PM) that the modulation sinusoidal signal on the birefringent phase modulator generates by signal generator

φ _mIt is the phase modulation (PM) amplitude; J ₁(φ _m), J ₂(φ _m) be respectively that variable is φ _mSingle order, the second order Bessel's function

A is from light intensity signal S ₁The digital electronic signal that changes into, a _M1H, a _M2H, be respectively first harmonic and the second harmonic of a.

B is from light intensity signal S ₂The digital electronic signal that changes into, b _M1H, b _M2H, be respectively first harmonic and the second harmonic of b.

The value of the electric field E to be measured that is obtained in the method and the fluctuation of the intensity of light source are irrelevant.

Control remaining optics phase bias Δ φ by dynamic monitoring ₀Value with the variation of ectocine, miniature optical alterating and direct current field sensor system can monitor remaining optics phase bias Δ φ by following formula ₀Value:

And numerical compensation is because of Δ φ ₀Disturbed and the error of the measured DC electric field that variation is caused by extraneous all kinds of factor, obtain DC electric field value to be measured in this way accurately.

This method also can be used for measuring AC field from miniature optical alterating and direct current field sensor output signal.

By the above electric field value that obtains, just can obtain magnitude of voltage to be measured through the numerical integration algorithm calculating identical with above-mentioned all embodiment.

It should be noted that at last: above embodiment only in order to the explanation the utility model, and and the described technical scheme of unrestricted the utility model; Therefore although this instructions explains the utility model with reference to each above-mentioned example, those of ordinary skill in the art should be appreciated that still and can make amendment or be equal to replacement the utility model; And all do not break away from the technical scheme and the improvement thereof of spirit and scope of the present utility model, all should be encompassed in the middle of the claim scope of the present utility model.

Claims (18)

1. distributed optical voltage transformer comprises:

The optical electric-field sensing unit, described optical electric-field sensing unit comprises light source, optical fiber, a plurality of miniature optical electric-field sensors and photodetector, described miniature optical electric-field sensor comprises electro-optic crystal;

Dielectric barrier insulation unit; Described dielectric barrier insulation unit comprises the electric insulation section that is made of dielectric material and lays respectively at two conductor electrodes that electric insulation section two ends spacing distance is L that voltage to be measured is added on described two conductor electrodes;

Data processing unit is used to receive the signal of optical electric-field sensing unit output, and calculates voltage to be measured;

Wherein a plurality of miniature optical electric-field sensors are transformed into optical signalling with the electric field that voltage to be measured generates, and through described photodetector conversion input data processing unit, data processing unit utilizes numerical integration method to calculate voltage to be measured;

It is characterized in that: the electro-optic crystal optical axis in the described miniature optical electric-field sensor is parallel with detection light beam and direction of an electric field to be measured, and promptly electro-optic crystal is in vertical orientation.

2. according to the distributed optical voltage transformer of claim 1, it is characterized in that: described electro-optic crystal is Bi ₄Ge ₃O ₁₂Crystal.

3. according to the distributed optical voltage transformer of claim 1, it is characterized in that: described a plurality of miniature optical electric-field sensors are distributed on the axis, described electric insulation intersegmental part zone, i.e. the coordinate place that provides with Gauss's numerical integrating on the z axis.

4. according to the distributed optical voltage transformer of claim 1, it is characterized in that: described data processing unit is according to following formula

$V=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\α}}_i{E}_i$

Calculate the data processing unit of voltage to be measured, wherein:

N is 〉=1 integer, and the number of expression miniature optical electric-field sensor;

E _iBe at distance lower end electrode z _iI the electric field value that the miniature optical electric-field sensor is measured of distance,

α _iBe and i the corresponding weight factor of the measured electric field value of miniature optical electric-field sensor, wherein α _i, z _iSelection should make

$\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\α}}_{i}d{E}_i$

Become minimal value, wherein dE _iBe owing to interference such as extraneous stray electric field make at z _iThe electric field E of place _iThe variation that produces.

5. according to the distributed optical voltage transformer of claim 4, it is characterized in that: wherein data processing unit is to utilize Gauss's numerical integrating to select α _i, z _iSo that

$\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\α}}_i{\mathrm{dE}}_i$

Become minimizing data processing unit.

6. according to the distributed optical voltage transformer of claim 1, it is characterized in that: described a plurality of miniature optical electric-field sensors along the ratio of the length summation of direction of an electric field and two electrode separation L less than 2%.

7. according to the distributed optical voltage transformer of claim 1, it is characterized in that: described electric insulation section also comprises the hollow insulation tube and is placed in the resistor-type dielectric barrier pipe of above-mentioned hollow insulation tube inside.

8. according to the distributed optical voltage transformer of claim 7, it is characterized in that: described resistor-type dielectric barrier pipe two ends are respectively with two electrode adjacency.

9. according to the distributed optical voltage transformer of claim 1, it is characterized in that: described miniature optical electric-field sensor also comprises optical polariser, optical alignment coupling mechanism, optics quarter-wave plate, polarizing beam splitter.

10. according to the distributed optical voltage transformer of claim 1, it is characterized in that: described miniature optical electric-field sensor also comprises the online polarizer of optics, optical alignment coupling mechanism, the online quarter-wave plate of optics, polarizing beam splitter.

11. distributed optical voltage transformer according to claim 1, it is characterized in that: described optical electric-field sensing unit also comprises optical polariser, described miniature optical electric-field sensor also comprises the optical alignment coupling mechanism, optics quarter-wave plate, polarizing beam splitter.

12. the distributed optical voltage transformer according to claim 1 is characterized in that: described miniature optical electric-field sensor also comprises optical polariser, optical alignment coupling mechanism, optics quarter-wave plate, polarizing beam splitter, optical prism.

13. distributed optical voltage transformer according to claim 1, it is characterized in that: described optical electric-field sensing unit also comprises optical polariser, and described micro field sensor also comprises the optical alignment coupling mechanism, the optics quarter-wave plate, polarizing beam splitter, optical prism.

14. the distributed optical voltage transformer according to claim 12 or 13 is characterized in that: described optical prism is formed by an end of electro-optic crystal.

15. distributed optical voltage transformer according to claim 1, it is characterized in that: described optical electric-field sensing unit also comprises optical polariser, the birefringent phase modulator, signal generator, described miniature optical electric-field sensor also comprises the optics quarter-wave plate, unpolarized optical splitter, optical alignment coupling mechanism, analyzer.

16. distributed optical voltage transformer according to claim 1, it is characterized in that: described optical electric-field sensing unit also comprises the birefringent phase modulator, signal generator, described miniature optical electric-field sensor also comprises optical polariser, the optics quarter-wave plate, unpolarized optical splitter, optical alignment coupling mechanism, analyzer.

17. the distributed optical voltage transformer according to claim 9 is characterized in that: described optics quarter-wave plate is positioned at electro-optic crystal incident end.

18. the distributed optical voltage transformer according to claim 9 is characterized in that: described optics quarter-wave plate is positioned at the electro-optic crystal exit end.

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