CN103472378B - A kind of all-fiber Partial Discharge in Power Transformer detection system and detection method thereof - Google Patents
A kind of all-fiber Partial Discharge in Power Transformer detection system and detection method thereof Download PDFInfo
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Abstract
The present invention relates to a kind of all-fiber Partial Discharge in Power Transformer detection system and detection method thereof.This system comprises controller, transmitting device and pick-up unit, and pick-up unit comprises four groups of Fiber Bragg Grating FBG F-P sonacs, is being respectively equipped with fiber delay line between two between Fiber Bragg Grating FBG; Four groups of Fiber Bragg Grating FBG F-P sonacs and fluorescent probe are connected on optical fiber; Transmitting device is connected with pick-up unit by feed-through; Controller is connected with transmitting device.At computing end, received the mistiming of sound wave by four groups of sensors, and time-multiplexed time error is taken into account, calculate the position determining shelf depreciation; By the intensity of fluorescent probe stimulated emission light signal, calculate the Apparent discharge magnitude of shelf depreciation; By the contrast of sonac and fluorescent probe signal, judge system whether due to the erroneous judgement that external environmental interference causes, avoid misreport of system, have structure simple, be convenient to the advantage such as networking, electromagnetism interference.
Description
Technical field
The present invention relates to a kind of Partial Discharge in Power Transformer on-line monitoring technique, specifically relate to a kind of all-fiber Partial Discharge in Power Transformer detection system and detection method thereof.
Background technology
Large-scale High-Pressure power transmission and transforming equipment especially transformer is the basis ensureing power supply reliability, is also the basic guarantee that electric power safety is produced.Along with transmission of electricity, the improving constantly of power transformation ability, electric pressure is also improving constantly, and the reliability service of transformer and fault diagnosis seem all the more important.Shelf depreciation be cause electric power transformer insulated aging and cause the main cause that punctures.The detection of shelf depreciation be all the various phenomenons that produce with shelf depreciation for foundation, characterized the state of shelf depreciation by the physical quantity stating this phenomenon.Usually when insulating inner generation shelf depreciation, there will be many phenomenons: electric pulse, ultrasound wave, electromagnetic wave, light, heat and with some the new products generated or gaseous tension and chemical change phenomenon.According to above-mentioned physical appearance feature, Partial Discharge Detection means conventional at present have following several: the multiple method such as pulse current method, supercritical ultrasonics technology (AE, or title acoustic-emission), flash spotting, gas chromatography, ultrahigh frequency method (UHF).For existing pulse current method subject matter be poor anti jamming capability, the problem such as survey frequency is low, frequency band is narrow and the quantity of information that comprises is few; For supercritical ultrasonics technology, also there is serious electromagnetic interference problem in current piezoelectric ceramic ultrasonic sensor, although there is optical fibre ultrasonic sensor, sound wave is decayed in route of transmission, distortion serious, causes ultrasound wave substantially can not reflect the size of discharge capacity; Flash spotting subject matter is the location that cannot realize shelf depreciation; Vapor-phase chromatography detects poor real, and actual shelf depreciation wants delayed a few hours; Ultrahigh frequency method is used for Partial Discharge in Power Transformer and detects, and needs the uhf sensor of design specialized (sensor generally needs pre-buried or puts in transformer oil), and practical application is inconvenient.
Optical fiber has electromagnetism interference, electrical isolation, corrosion-resistant, the advantage of essential safety, utilizes optical fiber for the characteristic of the sensitivity response of sound wave and low-loss transmission to light, can make the partial discharge detecting sensor based based on supercritical ultrasonics technology and flash spotting accordingly.Such sensor based on optical fiber has the incomparable electromagnetism interference characteristic of traditional electrical class sensor, and can realize the mode of built-in installation, thus effective raising detection sensitivity and reliability.
Existing application number is 201010235704.9, denomination of invention is the detection that light signal that " detecting the system and method for Partial Discharge in Power Transformer with fluorescence optical fiber " utilizes shelf depreciation to produce carries out shelf depreciation, the method exist sensitivity low, cannot the problem such as orientation discharge source; Chinese patent 201020302185.9, denomination of invention utilize acoustic emission to detect partial discharge of transformer for " local discharging optical fiber detection device of transformer ", the method exist sensitivity low, be subject to the interference of extraneous ultrasonic signal, the problems such as Apparent discharge magnitude cannot be measured; Chinese patent 201110266331.6, denomination of invention are that " Partial Discharge in Power Transformer detection system and detection method based on Fiber Bragg Grating FBG " utilizes Fiber Bragg Grating FBG to detect the situation of partial discharge of transformer, the method is owing to using Fiber Bragg Grating FBG as sensing unit, therefore it exists by the large problem of influence of ambient vibration, be difficult to realize application in actual environment.
In addition, the probability distribution of discharge signal and interference is not generally completely clear and definite, there is many disturbing factors and all can cause interference to Partial Discharge Detection in actual environment, causes wrong report to occur.As the thunderbolt at thunderstorm weather can produce ultrasound wave, cause the wrong report of sonac.These uncertain factors all reduce the reliability of partial discharge monitoring system.
Summary of the invention
For the deficiencies in the prior art, the object of this invention is to provide a kind of all-fiber Partial Discharge in Power Transformer detection system, another object is to provide a kind of all-fiber Partial Discharge in Power Transformer detection method, have that structure is little, volume is simple, be convenient to the characteristic such as networking, electromagnetism interference, and inside transformer installation can be stretched into, the combination of Fiber Bragg Grating FBG F-P sonac and fluorescent probe can realize measurement and the location of shelf depreciation simultaneously, and the advantages such as the wrong report that external interference can be avoided to cause.The present invention can be widely used in the partial discharge monitoring of the power transformer of each grade and the location of discharge source.
The object of the invention is to adopt following technical proposals to realize:
The invention provides a kind of all-fiber Partial Discharge in Power Transformer detection system, described system comprises controller, transmitting device and pick-up unit, its improvements are, described pick-up unit comprises four groups of Fiber Bragg Grating FBG F-P sonacs, is being respectively equipped with fiber delay line between two between Fiber Bragg Grating FBG; Four groups of Fiber Bragg Grating FBG F-P sonacs and fluorescent probe are connected on optical fiber;
Described transmitting device is connected with pick-up unit by feed-through; Described controller is connected with transmitting device.
Further, described transmitting device is arranged on transformer external fiber, and transformer external fiber is connected by feed-through with inside transformer optical fiber;
Described transmitting device comprises LD pumping source, the first fiber coupler, the second fiber coupler, the first photodetector and the second photodetector;
Described LD pumping source is held with the A of the first fiber coupler and is connected, and its B end is connected with feed-through; The C end of described first fiber coupler is held with the D of the second fiber coupler and is connected, and the E end of the second fiber coupler is connected with the first photodetector; The F end of the second fiber coupler is connected with the second photodetector;
Described LD pumping source, the first photodetector are connected with controller respectively with the second photodetector.
Further, described feed-through adopts the through device of power transformer tank to realize, and described controller adopts computing machine to realize.
Further, described four groups of Fiber Bragg Grating FBG F-P sonacs and fluorescent probe to be connected on optical fiber and to be arranged on inside transformer.
Described four groups of Fiber Bragg Grating FBG F-P sonacs are respectively the first Fiber Bragg Grating FBG F-P sonac, the second Fiber Bragg Grating FBG F-P sonac, the 3rd Fiber Bragg Grating FBG F-P sonac and the 4th Fiber Bragg Grating FBG F-P sonac;
The first fiber delay line is provided with between described first Fiber Bragg Grating FBG F-P sonac and the second Fiber Bragg Grating FBG F-P sonac;
The second fiber delay line is provided with between the second Fiber Bragg Grating FBG ultrasonic sensor and the 3rd Fiber Bragg Grating FBG ultrasonic sensor;
The 3rd fiber delay line is provided with between the 3rd Fiber Bragg Grating FBG ultrasonic sensor and the 4th Fiber Bragg Grating FBG ultrasonic sensor.
Further, often organize Fiber Bragg Grating FBG F-P sonac and be made up of two Fiber Bragg Grating FBGs, described two Fiber Bragg Grating FBG reflectivity and transmissivity are 8%, and chamber is long is 7cm, and centre wavelength is 1550nm.
Further, described fluorescent probe is arranged on the end of inside transformer optical fiber;
Fluorescent probe is the surface by sensitive material being coated to testee, utilizes lens that exciting light and fluorescence are coupled to optical fiber; Fluorescent material is subject to exciting of shelf depreciation light signal, produces the light signal of new wave band.
Further, the fluorescent material of described fluorescent probe is magnesium fluorophosphate, and it excites wave band to be 250-500nm, and emission band is 600-700nm.
Further, the infrared semiconductor short-pulse laser of wavelength 1550nm centered by described LD pumping source.
Further, the splitting ratio of described first fiber coupler and the second fiber coupler is 50:50.
Further, described first photodetector is near infrared solid state photomultiplier pipe, spectral range 1000nm-1700nm; Described second photodetector is siliceous avalanche diode, spectral range 400nm-1100nm;
(function receiving the detector of fiber Bragg grating F-P ultrasonic sensing signal is mainly used for locating, and receives the detector of fluorescent probe signal for calculating the Apparent discharge magnitude of shelf depreciation for the Apparent discharge magnitude of shelf depreciation and the second photodetector.Two detectors are independent of each other, but can by the two whether have signal to export simultaneously, judge whether system is reported by mistake) output intensity be directly proportional.
Further, select the first photodetector of near infrared solid state photomultiplier pipe as the probe unit of four groups of Fiber Bragg Grating FBG F-P sonac light signals, select the probe unit of the second photodetector as fluorescent probe light signal of siliceous avalanche diode.
The present invention is based on a kind of all-fiber Partial Discharge in Power Transformer detection method that another object provides, its improvements are, the system of described method is all-fiber Partial Discharge in Power Transformer detection system, and described method comprises the steps:
<1>LD pumping source sends pulse laser, through the first fiber coupler, imports inside transformer optical fiber into by feed-through;
<2> pulse laser carries out reflecting and projecting through the first Fiber Bragg Grating FBG F-P sonac, the first fiber delay line, the second Fiber Bragg Grating FBG F-P ultrasonic sensor, the second fiber delay line, the 3rd Fiber Bragg Grating FBG F-P ultrasonic sensor, the 3rd fiber delay line and the 4th Fiber Bragg Grating FBG F-P sonac successively;
The optical signal transmission of <3> after reflection and transmission is to fluorescent probe, after fluorescent probe senses the light signal of shelf depreciation, being excited to produce wavelength is the light wave of 600-700nm, and together transmits with the reflected light through four groups of Fiber Bragg Grating FBG F-P ultrasonic sensors;
<4> reflected light signal and fluorescence excitation signal are transferred to transformer external fiber through feed-through, the second fiber coupler is transferred to again, respectively by the first photodetector and the second photoelectric detector through the first fiber coupler;
<5> first photodetector produces response to the reflected signal of Fiber Bragg Grating FBG F-P sonac, second photodetector produces response to fluorescence excitation signal, change light signal into electric signal respectively, and transfer to computing machine.
Further, in described step <5>, at computer disposal end, using Fiber Bragg Grating FBG F-P sonac and fluorescent probe mutually as reference signal, comprising:
If the first photodetector and the second photodetector receive the change of light signal simultaneously, then utilize the mistiming of the reflected signal of four groups of Fiber Bragg Grating FBG F-P sonacs, calculate the position of Partial Discharge Sources, utilize the light intensity of the optical excitation signal of fluorescent probe, calculate the Apparent discharge magnitude of shelf depreciation, and send alarm signal, by discharge information and position output display;
If the first photodetector and the second photodetector all do not receive the change of light signal, then detection system is failure to actuate;
If the first photoelectric detector to the change of light signal and the second photodetector do not receive the change of light signal or the first photodetector do not receive the change of light signal and the second photoelectric detector to the change of light signal, then be considered as wrong report situation, give a warning and detection system overhauled.
Compared with the prior art, the beneficial effect that the present invention reaches is:
All-fiber Partial Discharge in Power Transformer detection system provided by the invention and detection method advantage specific as follows:
1, all-fiber sensor-based system that the present invention proposes has that structure is little, volume is simple, be convenient to the characteristic such as networking, electromagnetism interference, and inside transformer installation can be stretched into, effectively avoid the complicacy due to inside transformer structure, cause the decay of ultrasonic signal, thus shelf depreciation situation can be monitored more accurately and effectively.
2, the invention solves supercritical ultrasonics technology and can only locate the disadvantage that the monitoring that cannot realize Apparent discharge magnitude and flash spotting cannot realize the location of shelf depreciation, effective combination of Fiber Bragg Grating FBG F-P sonac and fluorescent probe can be realized simultaneously measurement and the location of shelf depreciation, and the advantages such as the wrong report that external interference can be avoided to cause.The present invention can be widely used in the partial discharge monitoring of the power transformer of each grade and the location of discharge source.
3, the present invention is based on the principle that supercritical ultrasonics technology is combined with flash spotting, by the otherness of time-division multiplex technology and the reflecting light wave band of Fiber Bragg Grating FBG F-P ultrasonic sensor and the excitation light wave wave band of fluorescent probe, four groups of Fiber Bragg Grating FBG F-P ultrasonic sensors and fluorescent probe are serially connected on an optical fiber, respectively the optical excitation signal of ultrasonic sensor light signal and fluorescent probe is detected by the photodetector of two different operating wave bands, utilize the mistiming of four groups of Fiber Bragg Grating FBG F-P ultrasonic sensor Received signal strength, calculate partial discharge position, utilize the optical excitation signal intensity of fluorescent probe, calculate the Apparent discharge magnitude of shelf depreciation.By the combination of the two, while realization is measured and is located, both signals Fiber Bragg Grating FBG F-P sonac and fluorescent probe received, mutually as with reference to signal, as the foundation whether system normally works, effectively avoid external interference to cause the wrong report erroneous judgement situation of system.
Accompanying drawing explanation
Fig. 1 is Fiber Bragg Grating FBG F-P sonac structural drawing provided by the invention;
Fig. 2 is the reflected light spectrogram of Fiber Bragg Grating FBG F-P sonac provided by the invention;
Fig. 3 is the schematic diagram of ultrasonic method provided by the invention location Partial Discharge Sources;
Fig. 4 is shelf depreciation spectrogram provided by the invention;
Fig. 5 is that the fluorescent probe of magnesium fluorophosphate material provided by the invention excites and utilizing emitted light spectrogram;
Fig. 6 is all-fiber Partial Discharge in Power Transformer detection system structured flowchart provided by the invention;
Wherein: 1-LD pumping source, 2-first fiber coupler, the through device of 3-power transformer tank wall, 4-first Fiber Bragg Grating FBG F-P sonac, 5-first fiber delay line, 6-second Fiber Bragg Grating FBG F-P sonac, 7-second fiber delay line, 8-the 3rd Fiber Bragg Grating FBG F-P sonac, 9-the 3rd fiber delay line, 10-the 4th Fiber Bragg Grating FBG F-P sonac, 11-fluorescent probe, 12-transformer, 13-second fiber coupler, 14-first photodetector, 15-second photodetector, 16-computing machine;
Fig. 7 is flow chart of data processing figure provided by the invention.
Embodiment
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in further detail.
The principle of the invention is: supercritical ultrasonics technology is the ultrasound wave produced by the electric discharge of sonac local, and detect shelf depreciation thus, its frequency is typically chosen between 70-150kHz.Fiber Bragg Grating FBG F-P sonac, utilize two identical Bragg gratings as " catoptron ", form the Fabry-Perot based on Fiber Bragg Grating FBG (F-P) chamber, the structure of this double grating can effectively solve the problems such as grating cross sensitivity.The chamber that the compressional wave that ultrasonic signal produces will modulate F-P is long, by the move of stripe (light intensity) of demodulation Fiber Bragg Grating FBG F-P cavity reflected light, can realize hyperacoustic measurement, as depicted in figs. 1 and 2.The wave band of its reflected light is decided by light source, and the general infrared band of about 1550nm of selecting is as light source, and therefore the service band of photodetector is also selected at infrared band.
In 2D space, 2 A, B in known plane, if by mistiming of Acoustic Wave Propagation, determine the distance of space point C to A, B, can determine the position of a C in 2D plane by the triangle cosine law; Determine the position of discharge source S in the 3 d space, if 2 A (x in known spatial
1, y
1, z
1), B (x
2, y
2, z
2) locus, by the mistiming of Acoustic Wave Propagation, determine discharge source S and divide the distance being clipped to A, B, then still can not determine the position of discharge source S, but discharge source S by be defined in A, B sphere that is the center of circle on the round O that intersects, as shown in Figure 3; If known spatial point C (x again
3, y
3, z
3), and calculated the distance determining CD by mistiming of Acoustic Wave Propagation, then the position of S point is by being defined in round O and taking C as two point of intersection of sphere in the center of circle, therefore still needs the 4th spatial point D (x
4, y
4, z
4) determine the position of S, and the 4th spatial point A, B, C, D can not be coplanar.Therefore according to above analysis, by the position of supercritical ultrasonics technology determination Partial Discharge Sources, at least need 4 Fiber Bragg Grating FBG F-P sensors.Utilize following formula can try to achieve the position of space discharge source:
In formula, (x
i1, y
i1, z
i1) be that the volume coordinate of i-th sensor and first sensor is poor, r
i1the space length of i-th sensor to first sensor,
Flash spotting be the change of the light signal utilizing shelf depreciation to produce to detect shelf depreciation, the wave band of light wave that shelf depreciation produces between 240-405nm, as shown in Figure 4.The principle of fluorescent probe detection shelf depreciation is the photoluminescence principle of fluorescent material, when the external optical signals meeting fluorescence excitation wave band is radiated at phosphor surface, fluorescence will the light signal of the certain wave band of stimulated emission, by detecting the detection that this signal can realize shelf depreciation.Excitation light intensity and the Apparent discharge magnitude of fluorescence are proportional, therefore can realize the detection of Apparent discharge magnitude.Trivalent magnesium ion excite wave band between 250-500nm, cover shelf depreciation produce light-wave band, its excitation spectrum wave band at the visible light wave range of 600-700nm, as shown in Figure 5.Therefore the service band of its photodetector is selected at visible light wave range.
When photodetector operating voltage one timing, its anode output current can be expressed from the next:
i(t)＝GS
dP
s(t)……1）；
In formula, i (t) is anode output current, and G is current gain, S
dfor photo cathode sensitivity, P
st () is optical signal power.
The light signal produced due to PD is pulse signal, is also pulse signal, can not ignore, can be obtained by equivalent electrical circuit for pulse signal photodetector anode ground capacitance by the known anode output current of formula:
In formula, the output voltage that u (t) is photomultiplier, τ
1=R
1c
1, C is constant.Output voltage is differentiated and can be obtained:
Simultaneous formula 2) and 3) can obtain:
u(t)+τ
1u'(t)＝τ
1i(t)……4）；
Simultaneous formula 1) and 4) can obtain:
According to above-mentioned derivation, the luminous energy E that can obtain a PD optical sensor absorption is:
Single PD flash spotting signal is had
can be obtained by formula (6):
From light signal attenuation characteristic in media as well, the luminous energy E of a PD release
land the relation received between luminous energy E can be represented by the formula:
In formula, μ is the absorption coefficient of optical sensor, k
ξabsorption coefficient, L is the distance in sensor and PD source, and ρ is gas density.By formula 7) and 8) can obtain:
When photodetector operating voltage is certain, optical sensor and PD discharge source relative position certain, μ, G, S
d,
be constant, it can thus be appreciated that flash spotting signal integrated value characterizes in fact the luminous energy of PD release.
Based on the principle that supercritical ultrasonics technology is combined with flash spotting, by the otherness of time-division multiplex technology and the reflecting light wave band of Fiber Bragg Grating FBG F-P ultrasonic sensor and the excitation light wave wave band of fluorescent probe, four groups of Fiber Bragg Grating FBG F-P ultrasonic sensors and fluorescent probe are serially connected on an optical fiber, respectively the optical excitation signal of ultrasonic sensor light signal and fluorescent probe is detected by the photodetector of two different operating wave bands, utilize the mistiming of four groups of Fiber Bragg Grating FBG F-P ultrasonic sensor Received signal strength, calculate partial discharge position, utilize the optical excitation signal intensity of fluorescent probe, calculate the Apparent discharge magnitude of shelf depreciation, by the combination of the two, measure in realization and while location, effectively avoid the erroneous judgement situation that external interference causes.
All-fiber Partial Discharge in Power Transformer detection system structured flowchart provided by the invention as shown in Figure 6, comprises controller, transmitting device and pick-up unit, and controller adopts computing machine 16 to realize.
Pick-up unit is arranged on inside transformer, comprise four groups of Fiber Bragg Grating FBG F-P sonacs and fluorescent probe 11, be respectively the first Fiber Bragg Grating FBG F-P sonac 4, second Fiber Bragg Grating FBG F-P sonac the 6, the 3rd Fiber Bragg Grating FBG F-P sonac 8 and the 4th Fiber Bragg Grating FBG F-P sonac 10; First Fiber Bragg Grating FBG F-P sonac 4, second Fiber Bragg Grating FBG F-P sonac the 6, the 3rd Fiber Bragg Grating FBG F-P sonac the 8, the 4th Fiber Bragg Grating FBG F-P sonac 10 and fluorescent probe 11 are connected on one article of optical fiber, between the first Fiber Bragg Grating FBG F-P sonac 4 and the second Fiber Bragg Grating FBG F-P sonac 6, be provided with the first fiber delay line 5; The second fiber delay line 7 is provided with between the second Fiber Bragg Grating FBG ultrasonic sensor 6 and the 3rd Fiber Bragg Grating FBG ultrasonic sensor 8; The 3rd fiber delay line 9 is provided with between the 3rd Fiber Bragg Grating FBG F-P sonac 8 and the 4th Fiber Bragg Grating FBG F-P sonac 10.
Transmitting device comprises LD pumping source 1, first fiber coupler 2, power transformer tank wall through device 3, second fiber coupler 13, first photodetector 14 and the second photodetector 15; The C end of the first fiber coupler 2 is held with the D of the second fiber coupler 13 and is connected, and the E end of the second fiber coupler 13 is held with the F of the first photodetector 14, second fiber coupler 13 and is connected with the second photodetector 15; LD pumping source 1, first photodetector 13 is connected with computing machine 16 respectively with the second photodetector 15.Inside transformer optical fiber is connected by the through device 3 of power transformer tank wall with external fiber.
LD pumping source 1 selects infrared band semiconductor short-pulse laser.The selection of light source is very important for time division multiplex system.The wavelength chooses of infrared semiconductor short-pulse laser is 1550nm, has the advantages such as high-quantum efficiency, high brightness, impedance low in calories, can long-term stable operation.
Fiber coupler is a kind of optical passive component made by fused biconical taper method, and the signal transmission that can realize in optical fiber produces coupling in special coupled zone, and carries out power or Wavelength Assignment.The splitting ratio of first, second fiber coupler is 50:50.
Fiber Bragg Grating FBG F-P sonac utilizes two identical Fiber Bragg Grating FBGs as catoptron, and form a Fabry-Perot-type cavity, its structure as shown in Figure 1.Incident light produces multi beam coherent reflection light and transmitted light after interreflection and refraction on relative two sides, and the spectrogram that transmitted light beam is formed as shown in Figure 2.Grating transmissivity in described first, second, third and fourth Fiber Bragg Grating FBG F-P sonac is 8%, the long 7cm in chamber, centre wavelength 1550nm.
Fluorescent probe 11 is at the end of internal optical fiber, connect with 4 groups of Fiber Bragg Grating FBG F-P sonacs, when inside transformer produces shelf depreciation, its light signal produced will cause the fluorescence signal of fluorescent probe 11 stimulated emission wavelength 600nm-700nm, F end through the second fiber coupler 13 is connected with the second photodetector 15, the service band of the second photodetector 15 is between 400nm-1100nm, and the Apparent discharge magnitude of shelf depreciation is directly proportional to the output intensity of detector.
Fluorescent probe 11 is the surfaces by sensitive material being coated to testee, utilizes lens that exciting light and fluorescence are coupled to optical fiber.Fluorescent material is subject to exciting of shelf depreciation light signal, will produce the light signal of new wave band.The sensitive material of described fluorescent probe is magnesium fluorophosphate, and it excites wave band to be 250-500nm, and emission band is 600-700nm.
Photodetector is device light signal being changed into real-time electric signal.According to detection optical signal spectrum scope difference, often select the device of different material structure.Select near infrared solid state photomultiplier pipe as the probe unit of Fiber Bragg Grating FBG F-P sonac light signal in this example, select silicon PIN photoelectric diode as the probe unit of fluorescent probe light signal.
The present invention also provides a kind of all-fiber Partial Discharge in Power Transformer detection method, and its process flow diagram as shown in Figure 7, comprises the steps:
<1>LD pumping source 1 sends pulse laser, through the first fiber coupler 2, imports inside transformer optical fiber into by the through device 3 of power transformer tank wall;
<2> pulse laser is after the first Fiber Bragg Grating FBG F-P sonac 4, there is part light can return along original optical path, and transmission is transmitted by remaining part light, after the first fiber delay line 5, enter the second Fiber Bragg Grating FBG F-P ultrasonic sensor 6, there is again portion's dichroic reflection and return along original optical path, remaining light will continue transmission, after the second fiber delay line 7, import the 3rd Fiber Bragg Grating FBG F-P ultrasonic sensor 8 into, to import after the 3rd Fiber Bragg Grating FBG F-P sonac 8 still important part dichroic reflection fractional transmission into, transmitted light still has the transmission of part reflecting part after entering the 4th Fiber Bragg Grating FBG F-P sonac 10,
After <3> fluorescent probe 11 senses the light signal of shelf depreciation, will be excited to produce wavelength is the light wave of 600-700nm, and together transmits with the reflected light through each Fiber Bragg Grating FBG F-P ultrasonic sensor;
<4> reflected light signal and fluorescence excitation signal are transferred to external fiber through the through device 3 of power transformer tank wall, transfer to the second fiber coupler 13 through the first fiber coupler 2 again, received by the first photodetector 14 and the second photodetector 15 respectively; The service band of the first photodetector 14 is between 1000nm-1700nm, and extraneous ultrasonic signal will cause the movement of reflectance spectrum, cause the change of detector output intensity, thus realize the detection of ultrasonic signal.And due to the effect of intermediate retardation device 5,7,9, between each reflected light, will certain time delay be had, therefore can be determined the induced signal of each Fiber Bragg Grating FBG F-P sonac by the mistiming of photoelectric detector;
<5> is due to the difference of service band, first and second photodetector will produce response to the reflected signal of Fiber Bragg Grating FBG F-P sonac and fluorescence excitation signal respectively, change corresponding light signal into electric signal respectively, and transfer to computing machine 16.
At computing end, computing machine using Fiber Bragg Grating FBG F-P sonac and fluorescent probe mutually as reference signal, if first, second photodetector receives the change of light signal simultaneously, then utilize the mistiming of the reflected signal of 4 groups of Fiber Bragg Grating FBG F-P sonacs, calculate the position of Partial Discharge Sources, utilize the light intensity of the optical excitation signal of fluorescent probe, calculate the Apparent discharge magnitude of shelf depreciation, and send alarm signal, by discharge information and position output display; If first, second photodetector does not all receive the change of light signal, then system is failure to actuate; If the first photoelectric detector is to the change of light signal and the second photodetector is receive the change of light signal or the first photoelectric detector to the change of light signal and the second photodetector does not receive the change of light signal, then be considered as wrong report situation, give a warning and need overhaul detection system, flow process as shown in Figure 7.
The inventive method utilizes present system, at computing end, has children outside the state plan the mistiming that sensor receives sound wave, and time-multiplexed time error taken into account, calculate the position determining shelf depreciation by four groups of Fiber Bragg Grating FBG F-P; By the intensity of fluorescent probe stimulated emission light signal, calculate the Apparent discharge magnitude of shelf depreciation; By the contrast of sonac and fluorescent probe signal, judge system whether due to the erroneous judgement that external environmental interference causes, avoid misreport of system.
Finally should be noted that: above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit, although with reference to above-described embodiment to invention has been detailed description, those of ordinary skill in the field are to be understood that: still can modify to the specific embodiment of the present invention or equivalent replacement, and not departing from any amendment of spirit and scope of the invention or equivalent replacement, it all should be encompassed in the middle of right of the present invention.
Claims (7)
1. an all-fiber Partial Discharge in Power Transformer detection system, described system comprises controller, transmitting device and pick-up unit, it is characterized in that, described pick-up unit comprises four groups of Fiber Bragg Grating FBG F-P sonacs, is being respectively equipped with fiber delay line between two between Fiber Bragg Grating FBG; Four groups of Fiber Bragg Grating FBG F-P sonacs and fluorescent probe are connected on optical fiber;
Described transmitting device is connected with pick-up unit by feed-through; Described controller is connected with transmitting device;
Described transmitting device is arranged on described transformer external fiber, and described transformer external fiber is connected by feed-through with inside transformer optical fiber;
Described transmitting device comprises LD pumping source, the first fiber coupler, the second fiber coupler, the first photodetector and the second photodetector;
Described LD pumping source is held with the A of the first fiber coupler and is connected, and its B end is connected with feed-through; The C end of described first fiber coupler is held with the D of the second fiber coupler and is connected, and the E end of the second fiber coupler is connected with the first photodetector; The F end of the second fiber coupler is connected with the second photodetector;
Described LD pumping source, the first photodetector are connected with controller respectively with the second photodetector;
Described fluorescent probe is arranged on the end of inside transformer optical fiber;
Fluorescent probe is the surface by sensitive material being coated to testee, utilizes lens that exciting light and fluorescence are coupled to optical fiber; Fluorescent material is subject to exciting of shelf depreciation light signal, produces the light signal of new wave band;
The fluorescent material of described fluorescent probe is magnesium fluorophosphate, and it excites wave band to be 250-500nm, and emission band is 600-700nm;
The infrared semiconductor short-pulse laser of wavelength 1550nm centered by described LD pumping source;
The splitting ratio of described first fiber coupler and the second fiber coupler is 50:50;
Described first photodetector is near infrared solid state photomultiplier pipe, spectral range 1000nm-1700nm; Described second photodetector is siliceous avalanche diode, spectral range 400nm-1100nm;
The Apparent discharge magnitude of shelf depreciation is directly proportional to the output intensity of the second photodetector.
2. all-fiber Partial Discharge in Power Transformer detection system as claimed in claim 1, is characterized in that, described feed-through adopts the through device of power transformer tank to realize, and described controller adopts computing machine to realize.
3. all-fiber Partial Discharge in Power Transformer detection system as claimed in claim 1, is characterized in that, described four groups of Fiber Bragg Grating FBG F-P sonacs and fluorescent probe to be connected on optical fiber and to be arranged on inside transformer;
Described four groups of Fiber Bragg Grating FBG F-P sonacs are respectively the first Fiber Bragg Grating FBG F-P sonac, the second Fiber Bragg Grating FBG F-P sonac, the 3rd Fiber Bragg Grating FBG F-P sonac and the 4th Fiber Bragg Grating FBG F-P sonac;
The first fiber delay line is provided with between described first Fiber Bragg Grating FBG F-P sonac and the second Fiber Bragg Grating FBG F-P sonac;
The second fiber delay line is provided with between the second Fiber Bragg Grating FBG ultrasonic sensor and the 3rd Fiber Bragg Grating FBG ultrasonic sensor;
The 3rd fiber delay line is provided with between the 3rd Fiber Bragg Grating FBG ultrasonic sensor and the 4th Fiber Bragg Grating FBG ultrasonic sensor.
4. all-fiber Partial Discharge in Power Transformer detection system as claimed in claim 3, it is characterized in that, often organize Fiber Bragg Grating FBG F-P sonac to be made up of two Fiber Bragg Grating FBGs, described two Fiber Bragg Grating FBG reflectivity and transmissivity are 8%, chamber is long is 7cm, and centre wavelength is 1550nm.
5. all-fiber Partial Discharge in Power Transformer detection system as claimed in claim 1, it is characterized in that, select the first photodetector of near infrared solid state photomultiplier pipe as the probe unit of four groups of Fiber Bragg Grating FBG F-P sonac light signals, select the probe unit of the second photodetector as fluorescent probe light signal of siliceous avalanche diode.
6. an all-fiber Partial Discharge in Power Transformer detection method, is characterized in that, the system of described method is all-fiber Partial Discharge in Power Transformer detection system, and described method comprises the steps:
<1>LD pumping source sends pulse laser, through the first fiber coupler, imports inside transformer optical fiber into by feed-through;
<2> pulse laser carries out reflecting and projecting through the first Fiber Bragg Grating FBG F-P sonac, the first fiber delay line, the second Fiber Bragg Grating FBG F-P ultrasonic sensor, the second fiber delay line, the 3rd Fiber Bragg Grating FBG F-P ultrasonic sensor, the 3rd fiber delay line and the 4th Fiber Bragg Grating FBG F-P sonac successively;
The optical signal transmission of <3> after reflection and transmission is to fluorescent probe, after fluorescent probe senses the light signal of shelf depreciation, being excited to produce wavelength is the light wave of 600-700nm, and together transmits with the reflected light through four groups of Fiber Bragg Grating FBG F-P ultrasonic sensors;
<4> reflected light signal and fluorescence excitation signal are transferred to transformer external fiber through feed-through, the second fiber coupler is transferred to again, respectively by the first photodetector and the second photoelectric detector through the first fiber coupler;
<5> first photodetector produces response to the reflected signal of Fiber Bragg Grating FBG F-P sonac, second photodetector produces response to fluorescence excitation signal, change light signal into electric signal respectively, and transfer to computing machine.
7. all-fiber Partial Discharge in Power Transformer detection method as claimed in claim 6, it is characterized in that, in described step <5>, at computer disposal end, using Fiber Bragg Grating FBG F-P sonac and fluorescent probe mutually as reference signal, comprising:
If the first photodetector and the second photodetector receive the change of light signal simultaneously, then utilize the mistiming of the reflected signal of four groups of Fiber Bragg Grating FBG F-P sonacs, calculate the position of Partial Discharge Sources, utilize the light intensity of the optical excitation signal of fluorescent probe, calculate the Apparent discharge magnitude of shelf depreciation, and send alarm signal, by discharge information and position output display;
If the first photodetector and the second photodetector all do not receive the change of light signal, then detection system is failure to actuate;
If the first photoelectric detector to the change of light signal and the second photodetector do not receive the change of light signal or the first photodetector do not receive the change of light signal and the second photoelectric detector to the change of light signal, then be considered as wrong report situation, give a warning and detection system overhauled.
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