CN112213604A - Novel transformer oil impurity concentration change interference type monitoring device and method - Google Patents
Novel transformer oil impurity concentration change interference type monitoring device and method Download PDFInfo
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Abstract
The invention relates to a novel transformer oil impurity concentration change interference type monitoring Device and a method thereof. The lightning surge generator is an electric spark generating device and simulates a discharge phenomenon; the He-Ne laser can emit laser beams with the wavelength of 632.8nm, and the laser beams and the Michelson interferometer form an optical monitoring system to form interference fringes; the CCD camera is a semiconductor device that can convert an optical image into a digital signal and output the digital signal to a computer, and is a device that captures interference fringes. In the power system, the device takes the transformer oil as a measured object, and quantitatively reconstructs the phase field distribution of the transformer oil by extracting the information of an interferogram in the transformer, thereby achieving the aim of accurately and immediately monitoring the running state of the transformer.
Description
Technical Field
The invention relates to a transformer monitoring device, in particular to a novel transformer oil impurity concentration change interference type monitoring device and method.
Background
The application range of the transformer is very wide, and the transformer is one of the most important electric products in a power system, particularly a power transmission and transformation circuit. In order to ensure the reliability and the economy of power supply of a power system, the online monitoring and fault diagnosis of the transformer are carried out at the same time. According to the transformer structure, transformer oil is filled between the coils of the transformer, so that the dielectric constant is increased, the transformer is not easy to break down in the operation process, and the transformer is an important component of the transformer. During the long-term operation of the transformer, the transformer oil may be cracked and doped with impurities, which affects the normal operation of the transformer. How to adopt a convenient and fast method to carry out on-line monitoring on the operation state of the transformer and observe the pollution of particles in time so as to improve the operation reliability of transformer equipment of a transformer substation is one of the key problems which must be solved in the construction of intelligent power grids in China. The existing gas chromatography does not need field contact, has good safety, but needs field sampling and laboratory analysis, and has long time consumption and poor instantaneity; in addition, the detection procedure is complex, and certain requirements are imposed on the operation level of detection personnel; and the chromatographic column needs to be cleaned and replaced regularly, so that the cost is increased, the running state of each transformer cannot be monitored and mastered at any time, and early warning cannot be timely realized.
Power systems are the most important and potential market for power electronics applications, which are widely and importantly used throughout the production, transmission, distribution and use of electrical energy. With the development of scientific technology, power electronic products are increasingly diversified and complicated, power electronic components are monitored in real time, the components in a power electronic circuit are protected from being damaged under the conditions of overvoltage, overcurrent, surge, electromagnetic interference and the like, and the method is of great importance to the application of power electronics, particularly the application in a power system.
The electric spark discharge is an unstable discharge process, has obvious pulse characteristics and high breakdown voltage, and a volt-ampere characteristic curve during discharge is a negative value, namely, the current passing through a medium is increased along with the reduction of the voltage between electrodes, and the electric spark discharge is mainly generated in gas or liquid insulating materials and has certain destructiveness on insulation. After the insulation is damaged, electric arcs can be generated among gaps or cracks of the insulation, the electric arcs can generate very high temperature, for example, 2-20A of electric arc current can generate local high temperature of 2000-4000 ℃, 0.5A of electric arc current can be enough to trigger fire, and secondary fire sources generated by electric sparks and electric arcs have higher danger. In addition, the electric spark belongs to open fire, the way of causing fire is direct, the electric spark has great threat to the safe operation of a power system, and the monitoring and the timely early warning of the electric spark are imperative.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, provides a novel transformer oil impurity concentration change interference type monitoring device and a novel transformer oil impurity concentration change interference type monitoring method, aims at solving the problems that the operation is complex, the time consumption is long, real-time online monitoring cannot be carried out and early warning cannot be carried out in time in the prior art, and provides the transformer oil impurity concentration change interference type monitoring device which can monitor the change of the impurity concentration of the transformer oil, further monitor whether the transformer has the phenomena of electric sparks, voltage and current jumps and the like in real time and carry out early warning in time.
The purpose of the invention can be realized by the following technical scheme:
the utility model provides a novel transformer oil impurity concentration changes interference formula monitoring devices, the device includes spectroscope and the thunderbolt surge generator who is used for the additional electric field, the spectroscope uses self as the center, and four right directions all around are provided with camera, reflector M1, reflector M2 and the beam expanding lens that is used for catching interference fringe respectively, the beam expanding lens not with the just right opposite side of spectroscope still is equipped with the laser instrument that is used for as the light source, the positive negative pole of thunderbolt surge generator is connected with the plate electrode respectively, the positive negative pole of thunderbolt surge generator corresponds respectively the plate electrode set up in reflector M1 with between the spectroscope, the camera still is connected with the computer that is used for reappearing interference fringe monitoring results in real time.
Further, the camera adopts a CCD camera.
Further, the laser adopts a He-Ne laser.
Further, the laser beam wavelength of the laser is 632.8 nm.
Further, the beam expander includes a concave lens for directing the beam input and a convex lens for directing the beam output.
Further, the central heights of the beam expander, the beam splitter and the reflective mirror M2 are all consistent.
Further, the center heights of the camera, the beam splitter and the reflective mirror M1 are all consistent.
The invention also provides a monitoring method adopting the novel transformer oil impurity concentration change interference type monitoring device, which specifically comprises the following steps:
step 1: opening the laser, placing transformer oil to be tested in a light path between the spectroscope and the reflector M2 to generate interference, and acquiring interference fringes without external electromagnetic field interference by the camera and transmitting the interference fringes to the computer;
step 2: when actual monitoring is carried out, the lightning surge generator is turned on, the electric field in a light path is changed through the electrode plate connected with the lightning surge generator, and interference fringes which are deviated and deflected when external electromagnetic field interference exists are acquired by the camera and transmitted to the computer;
and step 3: and processing the interference fringes which are subjected to deviation and deflection when the external electromagnetic field interference exists and the interference fringes which are not subjected to the external electromagnetic field interference in the computer to obtain the phase difference between the interference fringes and the phase difference, further performing backstepping to obtain the electric field intensity, and giving an early warning if the electric field intensity exceeds a preset value, namely achieving the purposes of quantitatively monitoring the impurity concentration change of the transformer oil in real time and giving an early warning.
Further, the camera adopts a CCD camera, the laser adopts a He-Ne laser, and the laser beam wavelength of the laser is 632.8 nm.
Furthermore, the beam expander comprises a concave lens for guiding the light beam input and a convex lens for guiding the light beam output, the central heights of the beam expander, the beam splitter and the reflector M2 are all consistent, and the central heights of the camera, the beam splitter and the reflector M1 are all consistent.
Compared with the prior art, the invention has the following advantages:
(1) according to the interference type monitoring device for the impurity concentration change of the transformer oil, whether the transformer has electric sparks, voltage and current jumps and other phenomena is monitored in real time, early warning is conveniently made in time, and accidents such as fire disasters and damage of equipment or electronic components are avoided; the method can be applied to the field of power electronics, and can quantitatively calculate the electric field intensity around a device in the switching process by measuring the overshoot voltage and current caused by the switching process of a power electronic device, so as to be used as reference for parameter selection of the electronic device and design of a protection circuit; the quality of the transformer oil can be analyzed only by processing the extracted interferogram information through a computer, the purpose of monitoring the running state of the transformer in real time is finally achieved, the structure is simple, the cost is greatly reduced, contact is not needed, and the safety is good.
(2) In the application of the power system, the invention takes the transformer oil as a measured object, reconstructs the phase field distribution of the transformer oil by extracting the information of the transformer oil interferogram by an optical method, and further deduces other physical quantities of the transformer oil, such as: the refractive index can realize real-time, quantitative and high-sensitivity nondestructive detection, and the accurate and immediate on-line monitoring of the running state of the transformer can be realized.
(3) The application range of the transformer is very wide, and the transformer is one of the most important electric products in a power system, particularly a power transmission and transformation circuit. In order to ensure the reliability and the economy of power supply of a power system, the online monitoring and fault diagnosis of the transformer are carried out at the same time. One important component in transformers is transformer oil. During the long-term operation of the transformer, the transformer oil may be cracked and doped with impurities, which affects the normal operation of the transformer. How to adopt a convenient and fast method to carry out on-line monitoring on the running state of the transformer and eliminate the pollution of particles so as to improve the running reliability of transformer equipment of a transformer substation is one of the key problems which need to be solved in the construction of the intelligent power grid in China. Data show that the main factors influencing the insulating property of the transformer oil include applied voltage, oil purity, humidity, high temperature, oxidation and the like, and the change of the factors can cause the change of the dielectric constant of the transformer oil, so that the refractive index of the medium is changed along with the change of the dielectric constant. Based on the method, the quality of the transformer oil is measured by extracting the information of the interferogram in the transformer, the phase field distribution of the transformer oil is quantitatively reconstructed, the refractive index three-dimensional distribution of the transformer oil is inverted, and the change of the dielectric constant is accurately pushed out, so that the aim of accurately and immediately monitoring the running state of the transformer is fulfilled.
(4) In the actual online monitoring of the safe operation of some electronic components, the invention can directly use the electronic components as the tested object, and can monitor the deterioration condition of the transformer oil, the presence or absence of voltage or current jump, the occurrence of electric sparks and other phenomena by extracting the information of the component interference pattern, thereby being convenient for making early warning in time. With the development of high-frequency high power of modern power electronic technology, potential problems of a switching device in application are more and more prominent, and especially the problems of voltage and current overshoot caused in the switching process seriously affect the working efficiency and working reliability of an inverter. The field intensity device capable of back-calculating provided by the invention can provide necessary reference for overvoltage protection and buffer circuit design.
Drawings
FIG. 1 is a schematic view of the overall structure of the present invention;
in the figure, 1 is a lightning surge generator, 2 is a laser, 3 is a beam expander, 4 is a spectroscope, 5 is a reflector M1, 6 is a reflector M2, 7 is a camera, and 8 is a computer.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
1. The specific scheme of the invention is as follows:
as shown in figure 1, the device comprises a lightning surge generator as a generating device of an external electric field, an optical monitoring system consisting of a He-Ne laser and a Michelson interferometer, and a CCD camera as a capturing device of interference fringes.
The lightning surge generator can simulate the discharge phenomena of different voltage levels through arrangement, and the periphery of the electric spark is accompanied with electric fields with different intensities;
the He-Ne laser can emit laser beams with the wavelength of 632.8nm, the Michelson interferometer consists of a beam expander, a beam splitter, reflectors M1 and M2, the beam expander comprises an input concave lens and an output convex lens, the concave lens transmits a virtual focal length light beam to the convex lens, the focal points of the two lenses are overlapped, the central heights of the beam expander, the beam splitter and the reflector M2 are kept consistent, and the centers of the reflector M1, the beam splitter and the CCD camera are kept in the same straight line; the measured system is placed in the object light path of the interferometer, and the He-Ne laser and the Michelson interferometer form an optical monitoring system. When no external electromagnetic field interference exists, the interference of the passing laser beams can be realized by adjusting the interferometer, and parallel interference fringes with equal intervals between bright and dark are generated;
the CCD camera can transmit the acquired image to a computer after processing through photoelectric conversion, and real-time reproduction of interference fringes on a computer interface is realized.
The method comprises the following steps that measured transformer oil is placed in an object light path of a Michelson interferometer, a lightning surge generator is connected with a measured system, when an external electric field is applied, laser emitted by a laser enters the Michelson interferometer, interference occurs after interference occurs, signals are collected by a CCD camera, interference fringes of deviation and deflection are obtained, after detail information of the fringes is extracted, phase field distribution is reconstructed, and electric field intensity at a sudden change moment is reversely deduced to be used as a reference;
the measured transformer oil is placed in an object light path of the Michelson interferometer, when the measured transformer oil is in a monitoring state, the impurity concentration of the measured transformer oil changes, laser emitted by a laser enters the Michelson interferometer, a CCD camera collects signals to obtain corresponding interference fringes, the interference fringes are compared and checked with information generated by an external electric field applied by a lightning surge generator, the electric field strength when the impurity concentration of the transformer oil changes is reversely deduced, the deterioration condition grade of the transformer oil is set according to the obtained variation condition of the electric field strength, and the transformer oil is fed back and classified into three grades, namely low grade, medium grade and high grade. Once the obtained transformer oil deterioration condition reaches a high level, the system immediately gives an alarm.
If electric sparks are introduced into an object light path of the interferometer, namely additional phase difference is introduced into a reference light path, an electric field is generated around the interferometer light path, so that the light path is affected, interference fringes are finally deviated, the CCD camera captures the deviated interference fringes at the same time and outputs the interference fringes to the computer, and the deviated interference fringes can be reproduced on the interface of the computer in real time. And then, the computer is used for processing the interference fringes under the two conditions of the existence of the applied external electric field, and the electric field intensity when the electric spark occurs can be reversely deduced by calculating the introduced additional phase difference, so that the impurity concentration in the transformer oil is judged.
2. The invention has the following specific principles:
transformer oil impurity concentration changes interferometric monitoring devices for on-line monitoring transformer running state, the device includes: the device for generating an external electric field, namely a lightning surge generator 1, an optical monitoring system consisting of a He-Ne laser 2 and a Michelson interferometer, and the device for capturing interference fringes, namely a CCD camera 7. The lightning surge generator 1 can simulate the discharge phenomena of different voltage levels through arrangement, electric fields with different intensities can be generated around electric sparks, and the lightning surge generator 1 is connected with the tested transformer oil; the He-Ne laser 2 can emit laser beams with the wavelength of 632.8 nm; the Michelson interferometer consists of a beam expander 3, a spectroscope 4 and two reflectors M1 and M2; the beam expander 3 is composed of a pair of convex-concave lenses arranged on the same optical axis, and is used for changing the diameter and the emission angle of the laser beam, so that observation is facilitated; the spectroscope 4 is an optical device that divides one laser beam into a plurality of beams; the reflector reflects the laser beam back to enable the two coherent laser beams to be converged after reflection and generate interference; the system to be measured is placed in the object light path of the interferometer, and the laser 2 and the Michelson interferometer form an optical monitoring system. When no external electromagnetic field interference exists, the interferometer is adjusted to enable the passing laser beams to interfere, and the interference is received by the CCD camera 7 and sent to the computer 8 to obtain parallel interference fringes with light and shade at equal intervals.
In the test, the tested system simulates electric sparks with different voltage levels after the lightning surge generator is set. During discharging, an electric field is generated around the electric spark, namely, an external electric field is applied to an object light path of the interferometer, namely, a phase difference is introduced into a reference light path, so that parallel and equidistant interference fringes with light and dark phases can be deviated and deflected, a CCD (charge coupled device) camera can capture the changed interference fringes at the same time and transmit the interference fringes to a computer, and real-time reproduction on a computer interface is realized. The computer is used for processing the interference fringes before and after the deviation, and the corresponding electric field intensity of the transformer oil with different concentrations of impurities can be reversely deduced by calculating the introduced phase difference.
In the monitoring of power electronic components, the system to be tested is an electronic component. When voltage or current suddenly changes, electromagnetic field is generated around the voltage or current, interference fringes of the interferometer are interfered, the fringes are shifted and deflected, after detail information of the fringes is extracted, phase field distribution is reconstructed, electric field intensity at the sudden change moment is reversely deduced, the change range of the voltage or current and the influence degree of the change on a circuit are conveniently analyzed, early warning is conveniently made in time, and reference is made for parameter selection of electronic devices and design of protection circuits.
And in the monitoring of the running state of the transformer, transformer oil is used as the system to be tested. By the same method, whether electric sparks exist around the transformer or not can be monitored, the quality of the transformer oil can be measured by extracting information of an interference pattern in the transformer and comparing and checking the information with information generated by applying an external electric field by using a lightning surge generator, the phase field distribution of the transformer oil is quantitatively reconstructed, the refractive index three-dimensional distribution of the transformer oil is inverted, and the change of the dielectric constant is accurately deduced, so that the purpose of accurately and immediately monitoring the running state of the transformer is achieved.
3. The theory of the invention supports that:
in optics, the refractive index is defined as the ratio of the speed of light in vacuum to the speed in the medium, denoted n, i.e.:
wherein epsilonr，μrThe relative permittivity and the relative permeability are respectively.
For a typical non-ferromagnetic medium, there is μr≈1,
The dielectric constant reflects the electrical properties of the medium.
The optical path is defined as the product of the geometric path of light propagating in the medium and the refractive index of the medium, and the optical path difference of the two laser beams is:
Δl＝n1s1-n2s2
wherein n is1、n2And s1、s2The refractive index and the geometric path of the medium when the two coherent light beams propagate in the reference light path and the object light path respectively.
When the light wave advances by one wavelength, the phase of the light wave changes by 2 pi, and then only a proportionality coefficient of 2 pi/lambda exists between the light wave and the light wave. (lambda is the wavelength of light in vacuum)
When two coherent wave surfaces interfere by the wave-particle duality of light, the light intensity distribution function of the interference image is as follows:
i(x,y)＝a(x,y)+b(x,y)+cos[h0(x,y)]
wherein a (x, y) is light intensity distribution function, b (x, y) is amplitude of combined vibration of two beams of coherent light, and h is light intensity distribution function0(x, y) is a phase distribution function. Performing fast Fourier transform to the above formula, filtering redundant information such as background light, and extracting only the positive first-order spectrumThen, the inverse fourier transform is used to obtain a function c (x, y), and the phase distribution function with the measured object information is:
wherein Re [ c (x, y) ], Im [ c (x, y) ] are the real and imaginary parts of c (x, y), respectively.
An external electric field is introduced into an optical monitoring system, which is equivalent to introducing an additional phase difference into a reference light path of an interferometer, and the phase difference is generated in a mode derived from an electro-optic effect:
n＝a0+b1E+b2E2.......
wherein n is the effective refractive index, a0Refractive index of the medium in the absence of an applied electric field, E electric field strength of the applied electric field, b1、b2Are all constants, namely linear electro-optic coefficients and quadratic nonlinear electro-optic coefficients.
It should be noted that, when the device of the present invention is applied, the optical monitoring system needs to be adjusted until clear parallel interference fringes with equal intervals between bright and dark appear on the computer interface, referring to fig. 1, the specific adjusting process is as follows: firstly, adjusting the positions of all elements, wherein the beam expander comprises an input concave lens and an output convex lens, the input lens transmits a virtual focal length light beam to the output lens, the distance between the lenses is adjusted to enable the focuses of the light beams to coincide, the reflective mirror M1 is vertical to the reflective mirror M2, and the central heights of the beam expander, the beam splitter, the reflective mirror and the CCD camera are kept consistent; then, the laser is turned on, the CCD camera is connected with the computer, and the laser beams reach the centers of all the mirror surfaces by adjusting the height of the reflecting mirror and the position of the reflecting mirror from the spectroscope until clear interference fringes reappear on the computer interface.
4. Practical embodiment
The invention provides a novel transformer oil impurity concentration change interference type monitoring device which is used for quantitatively monitoring whether electric sparks are generated or not in real time and obtaining the impurity concentration of transformer oil from breakdown voltage at that time. Firstly, a tested transformer oil system is placed in a light path, an optical monitoring system is adjusted according to the method, and after clear interference fringes are seen on a computer interface, the voltage level of a lightning surge generator is modulated to generate electric sparks. At the moment of striking the electric spark, the voltage suddenly and sharply increases, an electromagnetic field is generated around the changed voltage, and the theory supports that the dielectric constant of the surrounding medium is changed, the refractive index is changed along with the change, the optical path difference and the phase difference of the two interference light beams are changed, and therefore, the interference fringes are deviated and bent. The main phase difference of the system is related to the action length of the electric field, assuming that the action range of the electric field is L, n is the effective refractive index of the medium, the main action is the square term of the external electric field, and the relationship between the phase of the optical wave and the optical path is deduced according to the principle:
the method comprises the steps of utilizing electric sparks transmitted by a CCD camera to shoot front and back interference pictures and an FFT and unpacking algorithm in the principle, programming and restoring the real phase of light waves, calculating a phase difference, reversely deducing the electric field intensity, setting a preset value of the electric field intensity for alarming, and immediately giving an alarm once the electric field intensity is reversely deduced to exceed the preset value, so that the purposes of quantitatively monitoring the impurity concentration change in real time and alarming are achieved.
The device provided by the invention is used for monitoring the running state of the transformer quantitatively in real time in the embodiment. The set-up procedure of the system is exactly the same as in the above described embodiment. The device extracts the information of the interferogram in the transformer, and according to the principle and the embodiment, the phase field distribution of the transformer oil is reconstructed in a programming and quantitative mode, the three-dimensional distribution of the refractive index of the transformer oil is inverted, the change of the dielectric constant is accurately pushed out, the quality of the transformer oil is measured, and therefore the purpose of accurately and immediately monitoring the running state of the transformer is achieved.
While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A novel transformer oil impurity concentration change interference type monitoring device is characterized by comprising a spectroscope and a lightning surge generator (1) for an external electric field, the spectroscope (4) takes the spectroscope as a center, and a camera (7), a reflector M1(5), a reflector M2(6) and a beam expander (3) which are used for capturing interference fringes are respectively arranged in four opposite directions of front, back, left and right, the other side of the beam expanding lens (3) which is not opposite to the spectroscope (4) is also provided with a laser (2) used as a light source, the positive electrode and the negative electrode of the lightning surge generator (1) are respectively connected with the electrode plate, the electrode plates corresponding to the positive electrode and the negative electrode of the lightning surge generator (1) are arranged between the reflective mirror M1(5) and the spectroscope (4), the camera (7) is also connected with a computer (8) for reproducing the interference fringe monitoring result in real time.
2. The novel transformer oil impurity concentration change interferometric monitoring device according to claim 1, characterized in that the camera (7) adopts a CCD camera.
3. The novel interferometric monitoring device for the concentration change of impurities in transformer oil as claimed in claim 1, characterized in that the laser (2) is He-Ne laser.
4. A novel interferometric monitoring device for the impurity concentration variation of transformer oil as claimed in claim 3, characterized in that the laser beam wavelength of the laser (2) is 632.8 nm.
5. The novel interferometric monitoring device for the impurity concentration change of transformer oil as claimed in claim 1, characterized in that the beam expander (3) comprises a concave lens for guiding the light beam input and a convex lens for guiding the light beam output.
6. The novel interferometric monitoring device for the impurity concentration change of transformer oil as claimed in claim 1, wherein the beam expander (3), the spectroscope (4) and the reflector M2(6) are all consistent in central height.
7. The novel transformer oil impurity concentration change interferometric monitoring device according to claim 1, characterized in that the center heights of the camera (7), the spectroscope (4) and the reflector M1(5) are all consistent.
8. A monitoring method adopting the novel transformer oil impurity concentration change interferometric monitoring device as claimed in any one of claims 1 to 7, characterized in that the method specifically comprises the following steps:
step 1: opening the laser (2), placing transformer oil to be measured in a light path between the spectroscope (4) and the reflector M2(6), interfering, and acquiring interference fringes without external electromagnetic field interference by the camera (7) and transmitting the interference fringes to the computer (8);
step 2: when actual monitoring is carried out, the lightning surge generator (1) is opened, an electric field in a light path is changed through the electrode plate connected with the lightning surge generator, interference fringes which are deviated and deflected when external electromagnetic field interference exists are acquired by the camera (7) and are transmitted to the computer (8);
and step 3: and (3) processing the interference fringes which are subjected to deviation and deflection when external electromagnetic field interference exists and the interference fringes which are not subjected to external electromagnetic field interference in the computer (8) to obtain a phase difference between the interference fringes and the phase difference, further carrying out backstepping to obtain the electric field intensity, and giving an early warning if the electric field intensity exceeds a preset value, namely achieving the purposes of monitoring the impurity concentration change of the transformer oil in real time and quantitatively and giving an early warning.
9. The method for monitoring the concentration variation of the impurities in the transformer oil by the novel interferometric monitoring device for the concentration variation of the impurities in the transformer oil as claimed in claim 8, wherein the camera (7) is a CCD camera, the laser (2) is a He-Ne laser, and the wavelength of the laser beam of the laser (2) is 632.8 nm.
10. The novel transformer oil impurity concentration change interferometric monitoring device according to claim 8, characterized in that the beam expander (3) comprises a concave lens for guiding light beam input and a convex lens for guiding light beam output, the central heights of the beam expander (3), the beam splitter (4) and the reflector M2(6) are all consistent, and the central heights of the camera (7), the beam splitter (4) and the reflector M1(5) are all consistent.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114441479A (en) * | 2022-01-24 | 2022-05-06 | 上海电力大学 | Internal humidity detection device and detection method of electromagnetic field generation equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114441479A (en) * | 2022-01-24 | 2022-05-06 | 上海电力大学 | Internal humidity detection device and detection method of electromagnetic field generation equipment |
| CN114441479B (en) * | 2022-01-24 | 2023-10-31 | 上海电力大学 | Internal humidity detection device and detection method of electromagnetic field generation equipment |
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Application publication date: 20210112 Assignee: JIANGSU HANTANG ENVIRONMENTAL PROTECTION TECHNOLOGY Co.,Ltd. Assignor: Shanghai University of Electric Power Contract record no.: X2024310000010 Denomination of invention: A novel interferometric monitoring device and method for the variation of impurity concentration in transformer oil License type: Common License Record date: 20240115 |
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