CN104062569A - Method for detecting partial discharge direction of compound eye type optical fiber EFPI - Google Patents

Abstract

The invention belongs to the technical field of online monitoring of partial discharge of electric power paper oil insulation electrical equipment and relates to a method for detecting the partial discharge direction of a compound eye type optical fiber EFPI. A system for detecting the partial discharge direction of the compound eye type optical fiber EFPI is utilized; voltage signals output by five identical amplifiers are connected to an oscilloscope, power is supplied, a compound eye type optical fiber external cavity type Fabry-Perot sensor is placed at the top end of an insulating rod, and the insulating rod is rotated toward an optical fiber external cavity type Fabry-Perot sensing head with the strongest signal till the partial discharge pulse amplitude of an optical fiber external cavity type Fabry-Perot sensing head located in the middle is the largest and the partial discharge pulse amplitudes of optical fiber external cavity type Fabry-Perot sensing heads placed on the periphery are roughly equal; then, the orientation of the optical fiber external cavity type Fabry-Perot sensing head located in the middle in the compound eye type optical fiber external cavity type Fabry-Perot sensor is the direction of the partial discharge point. The method is high in sensitivity, good in directivity and high in anti-interference capacity and can be used for locating the partial discharge direction of key portions of electrical equipment conveniently and accurately.

Description

The shelf depreciation direction detection method of a kind of compound eye type optical fiber EFPI

Technical field

The present invention relates to the shelf depreciation direction detection method of a kind of compound eye type optical fiber EFPI, belong to electric power paper oil insulation local discharge of electrical equipment on-line monitoring technique field.

Background technology

Paper oil insulation electrical equipment (take transformer as main) partial discharge monitoring has several different methods both at home and abroad at present, mainly comprise very high frequency(VHF) (VHF) pulse current detection method, ultrahigh frequency (UHF) Electromagnetic Wave Detection method and piezoelectric sensor ultrasonic Detection Method, what wherein VHF and UHF detection method detected is electric signal, is easily subject to the interference of electromagnetic interference signal; What piezoelectric supersonic method detected is ultrasonic signal, and sensor is to be attached to the ultrasonic signal that on device housings, the inner shelf depreciation of checkout equipment produces, though be not vulnerable to the interference of electromagnetic noise, sensitivity is not high.Also there is the inside that piezoelectric sensor is placed on to device housings, in oil, detect shelf depreciation, but because piezoelectric supersonic sensor detection sensitivity in oil is not high, can not be placed on current potential higher position and measure, its detection method is restricted simultaneously.

The technology of optical method for measuring local discharge of electrical equipment has three kinds---direct detection visible ray method, Faraday magnetooptical effect method and light-supercritical ultrasonics technology.Direct detection visible ray method be only suitable in transparent dielectric as the high-voltage electrical equipment of insulating material, be not suitable for and using solid dielectric, the liquid dielectric Partial Discharge Detection as the high-voltage electrical equipment of insulating material; Light current sensor based on Faraday magnetooptical effect principle is only suitable for the Partial Discharge Detection of the high-voltage electrical equipment of solid shape, and the high-intensity magnetic field that can not get rid of from site space disturbs and cannot distinguish the electromagnetic pulse signal of crosstalking from high-voltage electrical equipment ground wire; Light-supercritical ultrasonics technology sensor has that volume is little, loss is low, it is little to disturb, the advantage of good insulation preformance and anti-explosion, anti-corrosion and being with a wide range of applications.

Light-supercritical ultrasonics technology comprises that fiber grating is surveyed ultrasonic vibration method and light interferes survey ultrasonic vibration method fiber optic interferometric method survey ultrasonic vibration to have three kinds of methods: optical fiber Michelson (Michelson) interferometric method, optical fiber mach-Ze Deer interfere (Mach-Zehnder) method and Fabry-Paro (Fabry-Perot) interferometric method.The sensitivity of Michelson method detection system is not high, and has the multipath problem of ultrasonic propagation; Not high enough, the complex structure of optical fiber mach-Ze Deer interferometric method frequency, demodulation frequency response is high to equipment requirement; Optical fiber Fabry-Paro rule has simple in structure, and volume is little, high reliability, and high sensitivity, Fast Time Response, antijamming capability is strong etc., and advantage receives the general concern of people.

Optical fiber EFPI (the extrinsic Fabry-Perotinterferometer of current domestic research, external cavity type Fabry-Paro interferometric sensor), the measurement that is mainly used in the gradual amounts such as temperature, strain, pressure, is still not suitable for high frequency Partial Discharge Detection fast.

Fiber external cavity formula enamel amber sensing head, generally, by optical fiber 01, insulating support 02, silicon sleeve pipe 03 and silicon thin film sheet 04, formed, method by carbon dioxide laser hot melt between silicon thin film sheet 04 and silicon sleeve pipe 03 realizes fixing seal, method by carbon dioxide laser hot melt between insulating support 02 and silicon sleeve pipe 03 realizes fixing seal, and insulating support 02 and optical fiber 01 method by carbon dioxide laser hot melt realizes fixing seal, the center-aligned of (will guarantee in the manufacturing process of sensing head) silicon thin film Pian04 center and optical fiber.

Summary of the invention

Object of the present invention is mainly used in the measurement of the gradual amounts such as temperature, strain, pressure for the optical fiber EFPI type sensor of domestic research, still be not suitable for the high frequency deficiency of Partial Discharge Detection fast, proposed the shelf depreciation direction detection method of a kind of compound eye type optical fiber EFPI.

Compound eye type optical fiber EFPI shelf depreciation direction detection system is comprised of narrow-band light source, optical filter, optical branching device, five identical optical circulators, five single-mode fibers, five identical photodetectors, five identical amplifiers, compound eye type fiber external cavity formula F-P sensor and oscillographs; Compound eye type fiber external cavity formula F-P sensor is comprised of five identical fiber external cavity formula enamel amber sensing heads, in the middle of among five identical fiber external cavity formula enamel amber sensing heads, a fiber external cavity formula enamel amber sensing head is positioned at, all the other four fiber external cavity formula enamel amber sensing heads are evenly placed surrounding, and are all miter angle with intermediate fibres external cavity type enamel amber sensing head.

Described narrow-band light source is connected with optical branching device successively with optical filter; Described optical branching device is divided into five light paths by the light after optical filter filters, and one of optical circulator that every light path is identical with five one of one of optical circulator, five single-mode fibers single-mode fiber, five identical fiber external cavity formula enamel amber sensing heads fiber external cavity formula enamel amber sensing head is connected successively; One of described five identical optical circulators optical circulator also again one of photodetector identical with five one of photodetector, five identical amplifiers amplifier be connected successively separately one by one; Five identical amplifiers are all connected with oscillograph.

According to the compound eye type optical fiber EFPI shelf depreciation direction detection method of this compound eye type optical fiber EFPI shelf depreciation direction detection system---

A shelf depreciation direction detection method of compound eye type optical fiber EFPI, the method comprises the following steps:

Step 1: utilize compound eye type optical fiber EFPI shelf depreciation direction detection system, the voltage signal of five identical amplifier outputs is connected on oscillographic five passages, oscillograph adopts edge from triggering mode, and triggering level is transferred to suitable position;

Step 2: power supply, makes each device in running order;

Step 3: the top that compound eye type fiber external cavity formula F-P sensor is placed on to insulating bar, the signal intensity of five passages of observation oscilloscope, when having shelf depreciation, five identical fiber external cavity formula enamel amber sensing heads (6) in described compound eye type fiber external cavity formula F-P sensor (10) all have the pulse signal of concussion; If the local discharge signal of the fiber external cavity formula enamel amber sensing head in the middle of being arranged in is not that five signals are the strongest, to the direction of the strongest fiber external cavity formula enamel amber sensing head of signal, rotate insulating bar;

Step 4: repeating step 3 is the fiber external cavity formula enamel amber sensing head in the middle of being positioned at until the passage of the amplitude maximum of pulse is put in office; The direction of fine setting fiber external cavity formula enamel amber sensing head, until pulse amplitude maximum is put in the office of the fiber external cavity formula enamel amber sensing head in the middle of being positioned at, and pulse amplitude is put about equally in the office that is positioned over the fiber external cavity formula enamel amber sensing head of surrounding; So, the fiber external cavity formula enamel amber sensing head in the middle of being positioned in compound eye type fiber external cavity formula F-P sensor towards, be the direction of shelf depreciation point.

The present invention can measure high-frequency signal delicately, for partial discharge monitoring.

Beneficial effect of the present invention:

1, the present invention have highly sensitive, good directionality, the feature that antijamming capability is strong, can suppress the impact that ultrasonic vibration multipath propagation brings.And sensor probe is little, can be used as a kind of point sensor, the keypoint part that is easily arranged on power equipment carries out the detection of shelf depreciation.

2, the present invention can measure high-frequency signal delicately, for partial discharge monitoring.

3, the present invention proposes the method that compound eye type sensor is determined shelf depreciation point direction first, and has designed five probe sensors, can easily and accurately carry out shelf depreciation direction location.

Accompanying drawing explanation

Fig. 1 is compound eye type optical fiber EFPI shelf depreciation direction detection system structural representation.

Fig. 2 is compound eye type fiber external cavity formula F-P sensor (solid) structural representation.

Fig. 3 is the structural representation of existing single fiber external cavity formula enamel amber sensing head.

Fig. 4 is light intensity and the long schematic diagram that is related to of film reflectivity and chamber.

Fig. 5 is in the maximum interval of light intensity peak peak value, and light intensity and chamber are grown is related to schematic diagram.

Fig. 6 is the Partial discharge signal schematic diagram that PD meter, optical fiber EFPI sensor and piezoceramic transducer detect.

When Fig. 7 is unloaded pressurization, the detection signal schematic diagram of PD meter, optical fiber EFPI sensor, piezoelectric ceramics.

Fig. 8 is the piezoceramic transducer dough softening, compound eye type fiber external cavity formula F-P sensor dough softening schematic diagram.Wherein, figure (a) is piezoceramic transducer dough softening schematic diagram; Figure (b) is compound eye type fiber external cavity formula F-P sensor dough softening schematic diagram.

Fig. 9 is that head angle arranges schematic diagram.

Figure 10 is 10～90 ° of angular response curve maps of optical fiber EFPI sensor.

Wherein, 1-narrow-band light source, 2-optical filter, 3-optical branching device, 4-optical circulator, 5 single-mode fibers,

6-fiber external cavity formula enamel amber sensing head, 7-photodetector, 8-amplifier, 9-oscillograph, 10-compound eye type fiber external cavity formula F-P sensor, 01-optical fiber, 02-insulating support, 03-silicon sleeve pipe, 04-silicon thin film sheet.

Embodiment

Below in conjunction with drawings and Examples, the present invention is described further.

Fig. 1 is compound eye type optical fiber EFPI shelf depreciation direction detection system structural representation.As shown in Figure 1, the monochromatic source that the wavelength of take fixes on 1310nm is example explanation, a kind of compound eye type optical fiber EFPI shelf depreciation direction detection system, and this system architecture is:

1) wavelength fixes on the monochromatic source of 1310nm, by narrow-band light source 1, by optical fiber filter, is filtered and is obtained monochromatic wavelength light source.Narrow-band light source 1 is selected SLED type light source, and wave filter is selected 1310nm fiber band-pass filter.

2) fiber selection 1310nm single-mode fiber, its center glass core diameter 9um, covering overall diameter 125um.Find after tested at 1310nm wavelength place, the total dispersion of single-mode fiber is zero.From the loss characteristic of optical fiber, 1310nm place is also a low loss window of optical fiber.So select light source of the present invention to be chosen in 1310nm place.

3) photodetector 7 is selected PIN photodiode, has the good linearity of incident light quantity and output current; Fast response time; Output error is little; The caused output change of variation of ambient temperature is little; Make simple; The feature that reliability is high.

4) optical fiber circulator is the incident light non-reciprocal device that reflected light is exported from another port from determining port output that only allows certain port.For assurance optical fiber, along specified path, propagate, need to use optical circulator 4.

5) due to present stage manufacturing technology reason, the hardware devices such as narrow-band light source 1, optical filter 2 can not guarantee that in process parameter is in full accord, and signal input also has dispersiveness, therefore, for reducing as far as possible the dispersiveness of test result, need to select optical branching device 3.

6) amplifier 8 of the photoelectricity of system adopts three grades of amplifications, and wherein every grade of amplifying circuit is consistent, and is together in series.Single-stage amplifying circuit as shown in Figure 1.Prime amplifier is selected OPA637.

7) design of fiber external cavity formula enamel amber sensing head

The design of fiber external cavity formula enamel amber sensing head is the core of compound eye type fiber external cavity formula F-P sensor system.As shown in Figure 2, Fig. 2 is compound eye type fiber external cavity formula F-P sensor (solid) structural representation to the structure of fiber external cavity formula enamel amber sensing head.In Fig. 2, can see silicon thin film sheet and silicon sleeve pipe non-perpendicular, but have certain angle.Fig. 3 is the structural representation of existing single fiber external cavity formula enamel amber sensing head, generally, a fiber external cavity formula enamel amber sensing head is comprised of optical fiber 01, insulating support 02, silicon sleeve pipe 03 and silicon thin film sheet 04, method by carbon dioxide laser hot melt realizes silicon thin film sheet 04 and silicon sleeve pipe 03, silicon sleeve pipe 03 and insulating support 02, and the fixing seal between insulating support 02 and optical fiber 01, in the manufacturing process of sensing head, to guarantee the center-aligned of silicon thin film Pian04 center and optical fiber 01.

Model, through emulation, is shown to angle is larger, and the response frequency of film is lower.The present invention adopts the structure that silicon thin film sheet 04 is vertical with silicon sleeve pipe 03.

A) design of silicon thin film sheet

Silicon thin film sheet adopts quartz film.The design of silicon thin film sheet comprises the sensitivity of film and determining of frequency response.The expression formula of the pressure sensitivity at diaphragm center is:

${\mathrm{\η}}_{\max }=\frac{Y_{\max }}{P}=\frac{3(1-{\mathrm{\μ}}^2)}{16E{h}^3}{R}^4---\left(1\right)$

The expression formula of minimum natural frequency is:

$f=2.749\×{10}^9\frac{h}{R^2}\left(\mathrm{Hz}\right)---\left(2\right)$

By formula, found, the pressure sensitivity of diaphragm is directly proportional to the biquadratic of its radius, is inversely proportional to the cube of thickness; And its natural frequency is directly proportional to the thickness of diaphragm, with square being inversely proportional to of effective radius.Sensitivity and frequency response are contradictories, therefore when design, take the way of compromise, make diaphragm reach best sensitivity and Hz-KHz.Selected radius R=0.9mm, thickness h=30, their highest frequency response and sensitivity are f=101.5kHz, η=0.4155.

B) cavity design of fiber external cavity formula enamel amber sensing head

When change of cavity length amplitude is larger, the light intensity of sensor output will be along with chamber long period variation.For the fiber external cavity formula enamel amber sensing head of range of linearity work, it is I that its initialization point requires to work as incident intensity at Q point ₀(λ), fiber end face reflectivity is R ₁=0.04, film internal surface reflection rate is R ₂, when the chamber length of fiber external cavity formula enamel amber sensing head is l, according to the theory of optics EFPI interferometer, can show that the output optical signal intensity of fiber external cavity formula enamel amber sensing head is:

$I_p\left(\mathrm{\λ}\right)=\frac{R_1+\mathrm{\η}{R}_2-2\sqrt{\mathrm{\η}{R}_1{R}_2}\cos \mathrm{\δ}}{1+\mathrm{\η}{R}_1{R}_2-2\sqrt{\mathrm{\η}{R}_1{R}_2}\cos \mathrm{\δ}}{I}_0\left(\mathrm{\λ}\right),---\left(3\right)$

In formula, it is the catoptrical optical path difference of two bundles.Intensity of reflected light and the contrast formula that by formula (3), can be derived sign sensor signal quality are:

$V=\frac{2\sqrt{R_1{R}_2}(1+R_1{R}_2-R_1-R_2)}{R_1+R_2+R_1^2{R}_2+R_1{R}_2^2-4R_1{R}_2},---\left(4\right)$

Loss correction factor η is:

$\mathrm{\η}={\mathrm{\η}}_1\×{\mathrm{\η}}_2\×{\mathrm{\η}}_3=0.9493{\mathrm{\η}}_1=0.9493{\left\{\frac{1}{1+{[2\mathrm{l\λ}/2\mathrm{\π}{n}_0{\mathrm{\ω}}^2]}^2}\right\}}^2---\left(5\right)$

By light source center wavelength 1310nm, n ₀=1.455 and ω=3.8 μ m substitution formulas (5).Interference light intensity is carried out to simulation result as shown in Figure 4, and Fig. 4 is light intensity and the long schematic diagram that is related to of film reflectivity and chamber.The reflectivity of film is when 0.35～0.36 interval, and the peak-to-peak value that light intensity changes is maximum, and it is very favorable for us, choosing quiescent point like this.

The long relation in light intensity to film reflectivity between 0.348～0.362 time and chamber is carried out emulation, obtains result as shown in Figure 5.Fig. 5 is in the maximum interval of light intensity peak peak value, and light intensity and chamber are grown is related to schematic diagram.According to analysis, determine that when chamber length is 50.58 μ m, light intensity mediates, namely suitable quiescent point Q.

8) compound eye type fiber external cavity formula F-P sensor design

The present invention proposes to adopt the many probe sensors of compound eye type to carry out the method for shelf depreciation point direction location first.Main thought be by a plurality of sensing heads by difference towards being grouped together, the voltage signal that measures towards the sensing head that approaches most shelf depreciation direction is maximum, carrys out accordingly to determine the direction of shelf depreciation point.Compound eye type fiber external cavity formula F-P sensor of the present invention is comprised of five identical fiber external cavity formula enamel amber sensing heads.The fiber external cavity formula enamel amber sensing head of five all, by identical parameters design, has identical performance.In the middle of a fiber external cavity formula enamel amber sensing head is positioned at, all the other four fiber external cavity formula enamel amber sensing heads are evenly placed surrounding, are all miter angle with middle sensing head.As shown in Figure 2.(Fig. 2 is compound eye type fiber external cavity formula F-P sensor (solid) structural representation.)

When measuring shelf depreciation, five fiber external cavity formula enamel amber sensing heads all have signal, but the fiber external cavity formula enamel amber sensing head signal that the most approaching office of direction puts is a little the strongest; Gradually sensor is turned to shelf depreciation point place, until the fiber external cavity formula enamel amber sensing head signal in the middle of being positioned at is the strongest, the fiber external cavity formula enamel amber sensing head signal that is placed in surrounding is basic identical, the fiber external cavity formula enamel amber sensing head in the middle of being now positioned at towards being shelf depreciation point direction.

Above these parts of the present invention, the annexation of a kind of compound eye type optical fiber of the present invention EFPI shelf depreciation direction detection system parts is:

1) building block is prepared: the present invention needs one of SLED type narrow-band light source, one of 1310nm fiber band-pass filter, 1 * 5 one of optical branching device, one of insulating bar of 5 Five-channel oscillographs of 5 amplifiers of the some photodetectors of the some BNC signal transmssion lines of 5 single-mode fibers of optical circulator;

2) by the designing requirement of compound eye type fiber external cavity formula F-P sensor and parameter, manufacture 5 of fiber external cavity formula enamel amber sensing heads.

3) by Fig. 1, assemble, with single-mode fiber, each device is coupled together.Manufacture the support of five pin, fix respectively 5 fiber external cavity formula enamel amber sensing heads, fiber external cavity formula enamel amber sensing head is arranged as Fig. 6, four fiber external cavity formula enamel amber sensing heads of surrounding all become miter angle with intermediate fibres external cavity type enamel amber sensing head, form compound eye type fiber external cavity formula F-P sensor.Fiber external cavity formula enamel amber sensing head is numbered to 1-5, and the fiber external cavity formula enamel amber sensing head mediating is numbered 1, and all the other four fiber external cavity formula enamel amber sensing heads are number consecutively 2-5 in the direction of the clock.Regulation No. 1 sensing head the compound eye type fiber external cavity formula that is oriented F-P sensor towards;

Narrow-band light source (1) is connected with optical branching device (3) successively with optical filter (2); Described compound eye type fiber external cavity formula F-P sensor (10) is comprised of five identical fiber external cavity formula enamel amber sensing heads (6); Described optical branching device (3) is divided into five light paths by the light after optical filter (2) filters, and one of optical circulator (4) that every light path is identical with five one of one of optical circulator, five single-mode fibers (5) single-mode fiber, five identical fiber external cavity formula enamel amber sensing heads (6) fiber external cavity formula enamel amber sensing head is connected successively; One of described five identical optical circulators (4) optical circulator also again one of photodetector (7) identical with five one of photodetector (7), five identical amplifiers (8) amplifier (8) be connected successively separately one by one; Five identical amplifiers (8) are all connected with oscillograph (9).

A kind of compound eye type optical fiber EFPI shelf depreciation direction detection method of compound eye type optical fiber EFPI shelf depreciation direction detection system is accordingly:

1) voltage signal of amplifier output is connected on oscillographic five passages, oscillograph adopts edge from triggering mode, and triggering level is transferred to suitable position.If each device of sensing head optics needs Power supply, mate suitable power supply.Make each device in running order.

2) compound eye type fiber external cavity formula F-P sensor is placed on insulating bar, can neatly sensor be placed in electrical equipment, carry out measurement of partial discharge.For example from head cover of transformer, put in transformer oil the shelf depreciation of measuring transformer paper oil insulation.

3) signal of five passages of observation oscilloscope, when having shelf depreciation, five passages all can have the pulse signal of concussion.If the signal of amplitude maximum is in 2-5 sensing head, mobile insulating bar makes the compound eye type sensor sensing head direction that slowly turn signal is the strongest.

4) repeating step 3, until the passage of the amplitude maximum of pulse is put in office, are 1 passage.The direction of fine setting compound eye type sensor, until pulse amplitude maximum is put in the office of 1 passage, and pulse amplitude is put about equally in the office of 2-5 passage.So, compound eye type sensor-type towards, namely No. 1 sensing head towards, be exactly the direction of shelf depreciation point substantially.

[performance verification experiment]:

The performance of sensing head of the present invention can be tested by the EFPI of single-path optical fiber shown in Fig. 1 pick-up unit.Paper oil insulation defect shelf depreciation model is set in laboratory, by pulse current method PD meter detection system, piezoceramic transducer system and single-path optical fiber EFPI detection system, measure respectively local discharge signal simultaneously, Fig. 6 is the Partial discharge signal schematic diagram that PD meter, optical fiber EFPI sensor and piezoceramic transducer detect, result as shown in Figure 7, when Fig. 7 is unloaded pressurization, the detection signal schematic diagram of PD meter, optical fiber EFPI sensor, piezoelectric ceramics.The sensing head of visible the present invention's design can detect local discharge signal well.

By the high-field electrode of shelf depreciation model---pin electrode takes off, other conditions are constant, and unloaded pressurization, is forced into 17kV, and the signal detecting as shown in Figure 7.Pass through Fig. 7, can obtain, in zero load, be pressurized to after 17kV, in environment, exist electromagnetic interference (EMI) or testing transformer to produce transaudient electromagnetic interference signal, PD meter detects discharge signal, and fiber ultrasonic wave sensor is corresponding with it without ultrasonic signal with piezoceramic transducer, this has also illustrated that ultrasonic sensor has good anti-electromagnetic interference capability, and optical fiber EFPI sensor is compared piezoceramic transducer and had better antijamming capability.

Optical fiber EFPI sensor ultrasound wave response amplitude under the ultrasound wave response amplitude of the optical fiber EFPI sensor under the different distance obtaining and 15cm is asked to ratio, then the lower 50 groups of data of each distance of statistics are averaged, the signal that same method detects piezoceramic transducer is processed, and can obtain dough softening curve as shown in Figure 8.Fig. 8 is the piezoceramic transducer dough softening, compound eye type fiber external cavity formula F-P sensor dough softening schematic diagram.Wherein, figure (a) is piezoceramic transducer dough softening schematic diagram; Figure (b) is compound eye type fiber external cavity formula F-P sensor dough softening schematic diagram.Can see that the decay of the relative optical fiber EFPI of piezoelectric ceramics dough softening sensor is very fast, at 30cm place, substantially can't detect local discharge signal, and the distance that optical fiber EFPI sensor is put source 75cm in distance office still can detect larger discharge signal, this proof optical fiber EFPI transducer sensitivity is higher, faint local discharge signal can be detected.

Optical fiber EFPI sensing head detection angles performance test a: sensing head is put a little over against office, and the sensing head of second identical parameters becomes angle α to place with it, and as shown in Figure 9, Fig. 9 is that head angle arranges schematic diagram to model.The response curve that the shelf depreciation amplitude that obtains fiber external cavity formula enamel amber sensing head changes with angle as shown in figure 10.Figure 10 is 10～90 ° of angular response curve maps of optical fiber EFPI sensor.Visible optical fiber external cavity type enamel amber sensing head is larger towards departing from shelf depreciation orientation angle, and the signal amplitude measuring is less, but how tube angulation is not placed, and can measure signal all the time can find range from interior.

The present invention proposes the method that compound eye type sensor is determined shelf depreciation point direction first, and has designed five probe sensors, can easily and accurately carry out shelf depreciation direction location.The present invention has highly sensitive, good directionality, and the feature that antijamming capability is strong, can suppress the impact that ultrasonic vibration multipath propagation brings.And sensor probe is little, can be used as a kind of point sensor, the keypoint part that is easily arranged on power equipment carries out the detection of shelf depreciation.The present invention can measure high-frequency signal delicately, for partial discharge monitoring.

The present invention is not limited to above-mentioned preferred forms; anyone can draw other various forms of products under enlightenment of the present invention; no matter but do any variation in its shape or structure; every have identical with a application or akin technical scheme, within all dropping on protection scope of the present invention.

Claims (1)

1. the shelf depreciation direction detection method of a compound eye type optical fiber EFPI, described compound eye type optical fiber EFPI is comprised of five identical fiber external cavity formula enamel amber sensing heads, in the middle of among five identical fiber external cavity formula enamel amber sensing heads, a fiber external cavity formula enamel amber sensing head is positioned at, all the other four fiber external cavity formula enamel amber sensing heads are evenly placed surrounding, and be all miter angle with intermediate fibres external cavity type enamel amber sensing head, compound eye type optical fiber EFPI and narrow-band light source, optical filter, optical branching device, five identical optical circulators, five single-mode fibers, five identical photodetectors, five identical amplifiers and oscillograph form compound eye type optical fiber EFPI shelf depreciation direction detection system, it is characterized in that, the method comprises the following steps:

Step 1: utilize compound eye type optical fiber EFPI shelf depreciation direction detection system, the voltage signal of five identical amplifier outputs is connected on oscillographic five passages, oscillograph adopts edge from triggering mode, and triggering level is transferred on position;

Step 2: power supply, makes each device in running order;

Step 3: the top that compound eye type fiber external cavity formula F-P sensor is placed on to insulating bar, the signal intensity of five passages of observation oscilloscope, when having shelf depreciation, five identical fiber external cavity formula enamel amber sensing heads in compound eye type fiber external cavity formula F-P sensor all have the pulse signal of concussion; If the local discharge signal of the fiber external cavity formula enamel amber sensing head in the middle of being arranged in is not that five signals are the strongest, to the direction of the strongest fiber external cavity formula enamel amber sensing head of signal, rotate insulating bar;

Step 4: repeating step 3 is the fiber external cavity formula enamel amber sensing head in the middle of being positioned at until the passage of the amplitude maximum of pulse is put in office; The direction of fine setting fiber external cavity formula enamel amber sensing head, until pulse amplitude maximum is put in the office of the fiber external cavity formula enamel amber sensing head in the middle of being positioned at, and pulse amplitude is put about equally in the office that is positioned over the fiber external cavity formula enamel amber sensing head of surrounding; So, the fiber external cavity formula enamel amber sensing head in the middle of being positioned in compound eye type fiber external cavity formula F-P sensor towards, be the direction of shelf depreciation point.