CN116297308A - Optical fiber type terahertz time-domain spectrum system - Google Patents
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 52
- 238000001228 spectrum Methods 0.000 title claims abstract description 20
- 239000000523 sample Substances 0.000 claims abstract description 86
- 238000001328 terahertz time-domain spectroscopy Methods 0.000 claims abstract description 27
- 238000010438 heat treatment Methods 0.000 claims abstract description 22
- 238000012360 testing method Methods 0.000 claims abstract description 22
- 238000001514 detection method Methods 0.000 claims abstract description 19
- 239000010453 quartz Substances 0.000 claims description 14
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 14
- 239000004065 semiconductor Substances 0.000 claims description 4
- 239000000835 fiber Substances 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 9
- 238000005259 measurement Methods 0.000 abstract description 7
- 230000003287 optical effect Effects 0.000 description 14
- 230000032683 aging Effects 0.000 description 13
- 239000000463 material Substances 0.000 description 11
- 238000005516 engineering process Methods 0.000 description 10
- 230000005540 biological transmission Effects 0.000 description 8
- 239000011810 insulating material Substances 0.000 description 8
- 230000008859 change Effects 0.000 description 6
- 238000010521 absorption reaction Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 230000008033 biological extinction Effects 0.000 description 4
- 230000008878 coupling Effects 0.000 description 4
- 238000010168 coupling process Methods 0.000 description 4
- 238000005859 coupling reaction Methods 0.000 description 4
- 238000003384 imaging method Methods 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
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- 230000002238 attenuated effect Effects 0.000 description 2
- 230000000875 corresponding effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000005672 electromagnetic field Effects 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
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- 238000011160 research Methods 0.000 description 2
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- 230000001427 coherent effect Effects 0.000 description 1
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- 238000009795 derivation Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000001819 mass spectrum Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
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- 239000007787 solid Substances 0.000 description 1
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- 238000002235 transmission spectroscopy Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3581—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using far infrared light; using Terahertz radiation
- G01N21/3586—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using far infrared light; using Terahertz radiation by Terahertz time domain spectroscopy [THz-TDS]
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
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Abstract
The invention relates to an optical fiber type terahertz time-domain spectroscopy system, which comprises: the optical fiber type terahertz time-domain spectrum detection device comprises a femtosecond optical fiber laser, a terahertz transmitting antenna, a terahertz receiving antenna, a bias high-voltage source, a lock-in amplifier and a computer, wherein the terahertz transmitting antenna and the terahertz receiving antenna are opposite to the transformer oil sample to be detected; the sample test bed comprises a sample tank, a heating device and a temperature sensing probe, wherein a transformer oil sample to be tested and the temperature sensing probe are both positioned in the sample tank, the heating device is attached to one side of the sample tank, and the heating device and the temperature sensing probe are both connected with a computer. Compared with the prior art, the terahertz time-domain spectrum measuring device and method for the transformer oil sample to be measured can realize real-time measurement of terahertz time-domain spectrums of the transformer oil sample to be measured at different temperatures, can finish the test in one step, are convenient to operate and high in efficiency, and can improve the accuracy of experimental results.
Description
Technical Field
The invention relates to the technical field of defect detection of power equipment, in particular to an optical fiber terahertz time-domain spectroscopy system.
Background
The optical parameters (such as refractive index and absorptivity) are macroscopic physical quantities for representing the optical properties of the material, and meanwhile microscopic properties of the material are indirectly reflected, and the terahertz time-domain spectroscopy technology can directly obtain the amplitude and phase information of the terahertz wave electromagnetic field, so that the optical parameters of the material in 2 modes of transmission and reflection can be directly obtained, and in practical application, a proper extraction mode can be selected according to specific situations.
Compared with a reflection mode, the transmission mode can obtain a higher signal-to-noise ratio, and the measurement result is more accurate and reliable, so that the terahertz time-domain spectroscopy technology is utilized to obtain the optical parameters of the insulating material in the transmission mode, the aging degree of the insulating material is characterized, and the refractive index, the extinction coefficient and the absorption coefficient of the sample to be measured are respectively obtained.
The terahertz time-domain spectroscopy technology is to induce terahertz pulse light to generate through femtosecond laser and realize terahertz pulse reconstruction through a high-precision delay equivalent time sampling mode, which is an efficient coherent detection mode, frequency domain signals containing sample amplitude and phase information can be obtained through simple Fourier transformation, and abundant physical information such as absorption coefficient, extinction coefficient, complex refractive index and the like can be obtained through simple post-processing, and can be used for supporting sample identification and quantitative analysis.
The terahertz time-domain spectroscopy technology also comprises a photoconductive emission antenna and a detection antenna, and the terahertz photoconductive antenna is a terahertz radiation source and a terahertz radiation detector which are most widely applied at present, are most reliable in operation and have the most excellent broadband radiation characteristic. Based on the ultra-fast carrier dynamics process of the photoconductive material induced by the femtosecond laser, terahertz signals with high signal to noise ratio up to a plurality of THz can be obtained, and the ultra-fast carrier dynamics process has excellent matching performance in the application of mass spectrum analysis.
In the aspect of the aging detection technology of the insulating material of the power equipment, the aging characteristics of the insulating surface skin of the cable under different aging conditions/aging years can be analyzed, macroscopic physical quantities representing the optical properties of the insulating material of the power cable are obtained, the aging characteristics of the insulating material of the power cable are represented, and the aging characteristic curve of the material is obtained by carrying out accelerated aging treatment on the material in the prior art, so that the performance of the material is evaluated.
However, for how to realize the aging characteristic detection of the insulating material of the power equipment in the accelerated aging process, the existing technology needs to be taken out after the accelerated aging of the material so as to detect the aging characteristic, the steps need to be performed, the operation is complex, and the accuracy of the experimental result is affected; and for the measurement of the performance of the transformer oil, the prior art still needs manual discrimination, and the accuracy is low.
Disclosure of Invention
The invention aims to overcome the defects that the prior art has the judgment on the performance of the transformer oil, the prior art still needs manual judgment, has low accuracy and no detection instrument with convenient operation and high precision, and provides an optical fiber terahertz time-domain spectrum system for realizing the performance measurement of the transformer oil.
The aim of the invention can be achieved by the following technical scheme:
a fiber-optic terahertz time-domain spectroscopy system, comprising: the optical fiber type terahertz time-domain spectrum detection device comprises a femtosecond optical fiber laser, a terahertz transmitting antenna and a terahertz receiving antenna, wherein the femtosecond optical fiber laser is connected with the terahertz transmitting antenna and the terahertz receiving antenna through optical fibers respectively, the terahertz transmitting antenna and the terahertz receiving antenna are opposite to the transformer oil sample to be detected, the terahertz transmitting antenna is also connected with a bias high-voltage source, and the terahertz receiving antenna is also sequentially connected with a phase-locked amplifier and a computer;
the sample test bed comprises a sample tank, a heating device and a temperature sensing probe, wherein the transformer oil sample to be tested and the temperature sensing probe are both positioned in the sample tank, the heating device is attached to one side of the sample tank, and the heating device and the temperature sensing probe are both connected with the computer.
Further, the sample cell is a quartz cuvette.
Further, the thickness of the quartz cuvette is in the range of 2.5-3.5 mm.
Further, the heating device is a semiconductor heater.
Further, the temperature sensing probe is a multichannel temperature sensor.
Further, the number of the temperature sensing probes is multiple, and each temperature sensing probe is uniformly distributed in the sample pool.
Further, the terahertz transmitting antenna and the terahertz receiving antenna are opposite to the surface of the transformer oil sample to be tested.
Further, the terahertz transmitting antenna and the terahertz receiving antenna are positioned on the same straight line.
Further, the model of the lock-in amplifier is SR830.
Further, an optical fiber delay line is connected in series between the femtosecond optical fiber laser and the terahertz receiving antenna.
Compared with the prior art, the invention has the following advantages:
(1) According to the invention, the quartz cuvette is used as a sample tank, so that terahertz pulses can penetrate through a transformer oil sample to be tested as much as possible; the terahertz transmitting antenna and the terahertz receiving antenna are opposite to the surface of the transformer oil sample to be tested, the heating device is tightly attached to one side of the quartz cuvette for heating, and the temperature sensing probe of the multichannel temperature sensor is arranged at 4 positions inside the quartz cuvette for monitoring the temperature change of the transformer oil in real time, so that the real-time measurement of the terahertz time-domain spectrum of the transformer oil sample to be tested at different temperatures is realized, the test can be completed in one step, the operation is convenient, the efficiency is high, and the accuracy of the experimental result can be improved.
(2) Because terahertz time-domain pulse signal power is smaller, if the thickness of transformer oil is too large and the transmitted terahertz pulse is too attenuated, clear pulse signals are difficult to obtain, and a test shows that the transformer is injected into a quartz cuvette with the thickness of 3.0mm, so that clear terahertz pulse signals can be obtained.
(3) The terahertz time-domain spectroscopy device adopting the optical fiber optical path coupling has the advantages of small volume, small mass, reliability and the like.
Drawings
Fig. 1 is a schematic diagram of a part of a structure of an optical fiber terahertz time-domain spectroscopy system according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an optical fiber terahertz time-domain spectrum detection device of an optical fiber terahertz time-domain spectrum system according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a transformer oil time domain test signal at different temperatures according to an embodiment of the present invention;
FIG. 4 is a schematic diagram showing time delay of transformer oil at different temperatures according to an embodiment of the present invention;
FIG. 5 is a graph showing the variation of the temperature and refractive index of transformer oil at a frequency of 0.2-1.6THz according to the embodiment of the present invention;
FIG. 6 is a graph showing the temperature and refractive index of transformer oil at a frequency of 0.85THz according to an embodiment of the present invention;
in the figure, 1, an optical fiber terahertz time-domain spectrum detection device, 11, a femtosecond optical fiber laser, 12, a terahertz transmitting antenna, 13, a terahertz receiving antenna, 14, a high-voltage source, 15, a lock-in amplifier, 16, a computer, 17, an optical fiber delay line, 2, a transformer oil sample to be detected, 3, a sample tank, 4, a heating device, 5 and a temperature sensing probe.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
In the description of the present invention, it should be noted that, directions or positional relationships indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are directions or positional relationships based on those shown in the drawings, or are directions or positional relationships conventionally put in use of the inventive product, are merely for convenience of describing the present invention and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be constructed and operated in a specific direction, and thus should not be construed as limiting the present invention.
It should be noted that the terms "first," "second," and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying a number of technical features being indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
Furthermore, the terms "horizontal," "vertical," and the like do not denote a requirement that the component be absolutely horizontal or overhang, but rather may be slightly inclined. As "horizontal" merely means that its direction is more horizontal than "vertical", and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.
Example 1
As shown in fig. 1 and 2, the present embodiment provides an optical fiber terahertz time-domain spectroscopy system, including: the optical fiber type terahertz time-domain spectrum detection device comprises a femtosecond optical fiber laser, a terahertz transmitting antenna and a terahertz receiving antenna, wherein the femtosecond optical fiber laser is connected with the terahertz transmitting antenna and the terahertz receiving antenna through optical fibers respectively, the terahertz transmitting antenna and the terahertz receiving antenna are opposite to the transformer oil sample to be detected, the terahertz transmitting antenna is also connected with a bias high-voltage source, and the terahertz receiving antenna is also sequentially connected with a phase-locked amplifier and a computer;
the sample test bed comprises a sample tank, a heating device and a temperature sensing probe, wherein the transformer oil sample to be tested and the temperature sensing probe are both positioned in the sample tank, the heating device is attached to one side of the sample tank, and the heating device and the temperature sensing probe are both connected with the computer.
The following describes the present system in detail:
1. optical fiber terahertz time-domain spectrum detection device
The optical parameters (such as refractive index and absorptivity) are macroscopic physical quantities for representing the optical properties of the material, and meanwhile microscopic properties of the material are indirectly reflected, and the terahertz time-domain spectroscopy technology can directly obtain the amplitude and phase information of the terahertz wave electromagnetic field, so that the optical parameters of the material in the transmission mode and the reflection mode can be directly obtained, and in practical application, a proper extraction mode can be selected according to specific situations.
Compared with the reflection mode, the transmission mode can obtain higher signal-to-noise ratio, and the measurement result is more accurate and reliable, so that the terahertz time-domain spectroscopy technology is utilized to obtain the optical parameters of the insulating material in the transmission mode, the aging degree of the insulating material is characterized, and the refractive index, the extinction coefficient and the absorption coefficient of the sample to be measured are respectively obtained, wherein the corresponding calculation formula can be as follows:
wherein: c is the speed of light in vacuum; omega is the angular frequency; d is the sample thickness.
By combining with the terahertz laser detection theory and utilizing the method for measuring the amplitude and the phase of the electric field by utilizing the terahertz laser pulse quantity in the derivation process, the optical parameters such as the refractive index, the absorption coefficient, the extinction coefficient and the like of the sample to be measured can be effectively obtained.
The terahertz time-domain spectroscopy device mainly comprises two modes of space optical path coupling and optical fiber optical path coupling, wherein the optical fiber coupling terahertz time-domain spectroscopy device has great advantages in the aspects of compactness, flexibility and environmental adaptability compared with the former due to the introduction of optical fibers. By means of system design (introduction of integrated optical fiber devices), optimized packaging (introduction of 3D packaging technology) and layout planning (spatial multiplexing, three-dimensional layout and the like) of the optical fiber devices, the terahertz time-domain spectroscopy device with small volume, small mass and reliability is expected to be obtained.
In this embodiment, optionally, the model of the lock-in amplifier is SR830. And an optical fiber delay line is connected in series between the femtosecond optical fiber laser and the terahertz receiving antenna.
The terahertz transmitting antenna and the terahertz receiving antenna are opposite to the surface of the transformer oil sample to be tested; the terahertz transmitting antenna and the terahertz receiving antenna are positioned on the same straight line.
2. Transformer oil sample and sample test bench to be tested
For the transformer oil sample to be tested and the sample test stand, the sample cell of the embodiment is preferably a quartz cuvette, and the thickness of the quartz cuvette is within the range of 2.5-3.5 mm.
The heating means may alternatively be a semiconductor heater.
The temperature sensing probes are multichannel temperature sensors, the number of the temperature sensing probes is multiple, and each temperature sensing probe is uniformly distributed in the sample cell.
According to the method, the performance of the transformer oil sample is detected by adopting the optical fiber type terahertz time-domain spectrum detection device, the traditional optical fiber type terahertz time-domain spectrum detection device is generally prepared by adopting a sample tabletting method when a solid sample is measured, and the transformer oil is oily liquid with fluidity, so that the sample tabletting method is not applicable any more.
Because terahertz time-domain pulse signal power is smaller, if the thickness of transformer oil is too large and the transmitted terahertz pulse is too attenuated, clear pulse signals are difficult to obtain, and a test shows that the transformer is injected into a quartz cuvette with the thickness of 3.0mm, so that clear terahertz pulse signals can be obtained.
The test heating device is a special semiconductor heater (TEC) heating device, the heating device is closely attached to one side of a quartz cuvette, the TEC is used for heating the quartz cuvette and transmitting heat to transformer oil in the cuvette, a temperature sensing probe of a multi-channel temperature sensor is arranged at 4 positions in the quartz cuvette and used for monitoring the temperature change of the transformer oil in real time, different voltages are applied to the TEC, continuous temperature change of the transformer oil temperature from 30 ℃ to 80 ℃ can be realized, terahertz time domain spectrums at six temperature points of 30 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃ and 80 ℃ are respectively obtained, the time delay condition of the front surface and the back surface of the transformer oil and the terahertz transmission spectrums of the transformer oil at different temperatures are obtained, and the refractive index and the absorption coefficient change of the transformer oil at different temperatures can be further related to the performance of the transformer oil.
The embodiment provides a test, which uses a terahertz time-domain spectroscopy system to perform transmission spectroscopy test on transformer oil samples at different temperatures, wherein the experimental environment temperature is 25 ℃ and the humidity is 30%, the transformer oil samples at different temperatures are placed at the focusing light spot position of a transmission light path, the sample placement surface is perpendicular to the incident direction of terahertz waves, and the time-domain acquisition length is 120ps. And carrying out multipoint sampling average in the to-be-tested area on each transformer oil sample to be tested, and ensuring the accuracy of the test result. The test results are shown in fig. 3, and the time domain signal delay of the transformer oil test sample gradually decreases as the transformer oil temperature increases.
The six curves from left to right represent the time domain signals after the transformer oil temperature is increased in turn, wherein the positions of the reflection peaks on the front surface are the same, and the time domain signal delay of the transformer oil with the same thickness along with the temperature increase can be reduced in fig. 4, namely the optical path difference of the terahertz wave propagating in the transformer oil with the same thickness is reduced.
The test is carried out at each interval of 1 ℃ between 30 ℃ and 80 ℃ and the test results are recorded, as shown in figure 4, the time delay length of the transformer oil corresponding to the same thickness gradually decreases along with the temperature rise of the transformer oil, and the delay conditions of the transformer oil at different temperatures can be obtained through the temperature and time delay curves, so that the performance of the transformer oil is related.
Terahertz imaging diagram of oilpaper sample and transformer oil characteristics at different temperatures
The test researches a method for measuring the oilpaper imaging by using the terahertz time-domain spectroscopy technology to obtain the following conclusion:
1) Terahertz waves are very sensitive to micro water in the oiled paper, and the time domain peak value/peak value time can be used as a characteristic value for rapidly identifying the micro water content of the oiled paper.
2) The higher the water content of the oiled paper is, the greater the polarization degree is, and the higher the loss is; as the frequency increases, the relaxation polarization of the oiled paper sample increases, resulting in a decrease in dielectric constant and an increase in dielectric loss.
3) The intensity data of terahertz imaging is positively correlated with the water content of the oiled paper, so that the terahertz imaging can be used as a characteristic quantity for detecting the water content of the oiled paper.
Based on the data, the refractive indexes of the transformer oil samples at different temperatures in the frequency range of 0.2-1.6THz can be obtained through further calculation and analysis, and the phenomenon that the refractive indexes of the transformer oil samples at different temperatures are obviously reduced along with the temperature rise can be obviously seen from experimental results (shown in figure 5).
The refractive index change trend of the transformer oil with the flatter 0.85THz frequency band is selected for calculation, as shown in FIG. 6. The characteristic of the transformer oil changes under the condition of temperature change, and the refractive index of the transformer oil changes to be smaller when the temperature is higher, so that the terahertz time-domain spectrum detection technology can be used for characteristic research of the transformer oil, and the measurement result is stable and reliable.
In summary, there is an approximate linear relationship between the terahertz time-domain transmission signal and the temperature of the insulating oil, and the delay time, refractive index and self temperature of the transformer oil are selected for analysis, and the test result can be used as a characteristic judgment basis for judging the transformer oil.
The foregoing describes in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be made in accordance with the concepts of the invention by one of ordinary skill in the art without undue burden. Therefore, all technical solutions which can be obtained by logic analysis, reasoning or limited experiments based on the prior art by the person skilled in the art according to the inventive concept shall be within the scope of protection defined by the claims.
Claims (10)
1. An optical fiber terahertz time-domain spectroscopy system, comprising: the optical fiber type terahertz time-domain spectrum detection device comprises an optical fiber type terahertz time-domain spectrum detection device (1), a transformer oil sample (2) to be detected and a sample test bed, wherein the optical fiber type terahertz time-domain spectrum detection device (1) comprises a femtosecond optical fiber laser (11), a terahertz transmitting antenna (12) and a terahertz receiving antenna (13), the femtosecond optical fiber laser (11) is connected with the terahertz transmitting antenna (12) and the terahertz receiving antenna (13) through optical fibers respectively, the terahertz transmitting antenna (12) and the terahertz receiving antenna (13) are opposite to the transformer oil sample (2) to be detected, the terahertz transmitting antenna (12) is also connected with a bias high-voltage source (14), and the terahertz receiving antenna (13) is also connected with a phase-locked amplifier (15) and a computer (16) in sequence;
the sample test bed comprises a sample tank (3), a heating device (4) and a temperature sensing probe (5), wherein a transformer oil sample (2) to be tested and the temperature sensing probe (5) are both positioned in the sample tank (3), the heating device (4) is attached to one side of the sample tank (3), and the heating device (4) and the temperature sensing probe (5) are both connected with a computer (16).
2. The optical fiber terahertz time-domain spectroscopy system according to claim 1, wherein the sample cell (3) is a quartz cuvette.
3. The fiber optic terahertz time-domain spectroscopy system according to claim 2, wherein the quartz cuvette has a thickness in the range of 2.5-3.5 mm.
4. An optical fiber terahertz time-domain spectroscopy system according to claim 1, characterized in that the heating device (4) is a semiconductor heater.
5. The optical fiber terahertz time-domain spectroscopy system according to claim 1, wherein the temperature sensing probe (5) is a multichannel temperature sensor.
6. The optical fiber terahertz time-domain spectroscopy system according to claim 1, wherein the number of the temperature sensing probes (5) is plural, and each temperature sensing probe (5) is uniformly distributed in the sample cell (3).
7. The optical fiber terahertz time-domain spectroscopy system according to claim 1, wherein the terahertz transmitting antenna (12) and the terahertz receiving antenna (13) are opposite to the surface of the transformer oil sample (2) to be measured.
8. An optical fiber terahertz time-domain spectroscopy system according to claim 1, characterized in that the terahertz transmitting antenna (12) and the terahertz receiving antenna (13) are located on the same straight line.
9. The optical fiber terahertz time-domain spectroscopy system according to claim 1, wherein the model number of the lock-in amplifier (15) is SR830.
10. The optical fiber terahertz time-domain spectroscopy system according to claim 1, wherein an optical fiber delay line (17) is connected in series between the femtosecond optical fiber laser (11) and the terahertz receiving antenna (13).
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116698784A (en) * | 2023-07-17 | 2023-09-05 | 南京电研电力自动化股份有限公司 | Acetylene monitoring device and method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116698784A (en) * | 2023-07-17 | 2023-09-05 | 南京电研电力自动化股份有限公司 | Acetylene monitoring device and method |
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