CN111157142A - Dry-type reactor temperature detection method based on distributed optical fiber sensing - Google Patents
Dry-type reactor temperature detection method based on distributed optical fiber sensing Download PDFInfo
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Abstract
本发明公开了一种基于分布式光纤传感的干式电抗器温度检测方法，属于电力检测技术领域，其包括以下步骤：S1：在干式电抗器上布设分布式光纤传感器；S2：构建干式电抗器磁场‑电路耦合模型，获得干式电抗器在正常运行过程中温度分布情况和发热点分布情况；S3：构建干式电抗器与周围空气流体温度场数学模型，获得光纤测量温度与干式电抗器包封温度之间的误差，构建温度补偿算法；S4：所述分布式光纤传感器通过波分复用器与基于拉曼散射的电抗器温度检测系统连接，使用所述基于拉曼散射的电抗器温度检测系统采集、处理所述分布式光纤传感器的信号，并显示处理后的干式电抗器温度信息。本发明检测面广，能够对干式电抗器连续监测，且检测精度高。
The invention discloses a dry-type reactor temperature detection method based on distributed optical fiber sensing, belonging to the technical field of electric power detection. The method comprises the following steps: S1: arranging distributed optical fiber sensors on the dry-type reactor; S2: constructing a dry The magnetic field-circuit coupling model of the dry-type reactor is used to obtain the temperature distribution and heating point distribution of the dry-type reactor during normal operation; S3: Build a mathematical model of the temperature field of the dry-type reactor and the surrounding air fluid, and obtain the optical fiber measurement temperature and dry-type reactor. S4: The distributed optical fiber sensor is connected with the Raman scattering-based reactor temperature detection system through a wavelength division multiplexer, and the Raman scattering-based reactor temperature detection system is The reactor temperature detection system of the device collects and processes the signal of the distributed optical fiber sensor, and displays the processed dry reactor temperature information. The invention has a wide detection range, can continuously monitor the dry type reactor, and has high detection accuracy.
Description
Technical Field
The invention relates to the technical field of power detection, in particular to a dry-type electric reactor temperature detection method based on distributed optical fiber sensing.
Background
The dry-type air-core reactor has the advantages of low loss, low noise, good linearity of reactance value, long design life, simple maintenance and the like, and is more and more widely applied to power systems. The device mainly plays a role in limiting switching-on inrush current, limiting short-circuit current, compensating stray capacitive current, filtering and the like in a system.
In the operation process of the dry-type reactor, the coil lead often contains impurities, or the insulation of the weftless glass ribbon of the epoxy resin encapsulated in the operation process is not good, and the like, so that the reactor can generate overhigh and overheating local temperature rise in the operation process, and finally the reactor is burned out and scrapped, thereby causing great loss to countries and enterprises. The distribution of the temperature field in the reactor is known, and the method has great significance for normal operation, fault prevention and the like of the reactor.
The dry-type reactor belongs to maintenance-free equipment, and the monitoring method is less, mainly adopts methods of regularly tracking and measuring the temperature of the dry-type reactor by adopting an infrared imager, installing a temperature on-line monitor below the dry-type reactor, directly attaching a temperature sensor to the encapsulation wall of the dry-type reactor, measuring the temperature by fiber bragg grating and the like, but has the defects of narrow effective monitoring surface, discontinuous monitoring process, low measuring precision, external working power supply, incapability of continuously measuring the temperature in a space range and the like, the practical application effect is not ideal, the heating point of the reactor cannot be found in time, and the phenomenon of burning the reactor sometimes occurs.
The patent with the publication number of CN 104266603B discloses a device for detecting the temperature and the strain of a dry-type air-core reactor on site, which is formed by connecting a Bragg fiber grating sensor (3) with an optical coupler (4), and connecting the optical coupler (4) with a fiber grating demodulator (5) through a jump fiber; the optical coupler (4) is formed by sequentially connecting a signal input channel (9), a programmable logic controller unit and a signal output channel (10). The invention solves the possibility that the dry-type air-core reactor is frequently burnt, can detect the temperature and the strain quantity on the surface of the drawing rod on line, reflects the working condition of the reactor during working, further reasonably switches the reactor, and has the advantages of safety and economy. However, the invention does not carry out finite element simulation on the dry-type reactor, has high blindness and can not ensure the detection accuracy.
Patent document CN 103674293 a discloses a dry reactor temperature detection system. The system detects the temperature of the dry-type reactor through a temperature detection device arranged in the dry-type reactor, and sends the detected temperature value to a monitoring terminal through a data transmission device. And when the monitoring terminal determines that the temperature in the dry-type reactor exceeds a preset temperature value, outputting an alarm signal. The system can detect the temperature of the dry-type reactor in real time, so that the dry-type reactor can quit operation in advance before a fire disaster occurs, and the loss is reduced to the minimum. However, this invention detects by providing a plurality of wireless temperature sensors in the reactor, and cannot accurately detect the position of the hot spot of the reactor.
Disclosure of Invention
In view of the above, the present invention provides a distributed optical fiber sensing-based dry reactor temperature detection method with comprehensive monitoring and high accuracy, which is directed to the defects of the prior art.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a dry-type reactor temperature detection method based on distributed optical fiber sensing comprises the following steps:
s1: distributing a distributed optical fiber sensor on the dry-type reactor;
s2: constructing a magnetic field-circuit coupling model of the dry-type reactor, and obtaining the temperature distribution condition and the heating point distribution condition of the dry-type reactor in the normal operation process;
s3: constructing a mathematical model of a temperature field of the dry reactor and ambient air fluid, obtaining an error between the optical fiber measurement temperature and the dry reactor encapsulation temperature, and constructing a temperature compensation algorithm;
s4: the distributed optical fiber sensor is connected with a reactor temperature detection system based on Raman scattering through a wavelength division multiplexer, the reactor temperature detection system based on Raman scattering is used for collecting and processing signals of the distributed optical fiber sensor, and processed dry-type reactor temperature information is displayed.
Furthermore, the distributed optical fiber sensor comprises an optical pulse laser, a photoelectric converter, a signal amplifier and a computer, wherein the pulse laser is in serial port communication with the computer, and the computer controls the pulse laser to emit optical pulses to enter the sensing optical fiber.
Further, the reactor temperature detection system based on Raman scattering comprises a signal acquisition unit, a denoising processing unit, a storage unit, a temperature demodulation unit and a display unit, wherein the wavelength division multiplexer divides the acquired light into anti-Stokes light and Stokes light, and the anti-Stokes light and the Stokes light are respectively subjected to photoelectric conversion and amplification and are respectively and sequentially transmitted to the signal acquisition unit, the denoising processing unit, the first storage unit, the temperature demodulation unit, the second storage unit and the display unit.
Further, in S2, a magnetic field-circuit coupling model of the dry reactor is constructed, and modeling is performed using a cylindrical coordinate system: under the cylindrical coordinate system, the control equation of the magnetic field is
In the formula: r is the radial distance under the cylindrical coordinate system; z is the axial distance; a is a magnetic vector bit; μ 0 is the magnetic permeability; j is the source current density.
The constraint equation of the ith layer coil by an external circuit is as follows:
wherein U is an external confinement voltage, Ri、ψi、Ni、Ii、SiThe resistance, flux linkage, number of turns, current, and cross-sectional area of the i-th layer coil are respectively.
The four equations are combined to establish a field-path coupling finite element equation, the current value and the vector magnetic potential of each layer of encapsulation can be obtained, and the magnetic induction intensity can be obtained from the vector magnetic potential
B＝▽×A
The i-th layer loss Pi of the winding mainly comprises resistive loss Pri and eddy current loss Pei, wherein the i-th layer of the winding has loss of
In the formula: gamma is the resistivity of the wire; ω is the angular frequency of the applied excitation; diIs as followsThe wire diameter of the i turns of conducting wires; i isiThe radius of each turn of wire; b isiThe magnetic induction intensity at the center of the ith turn of the wire.
Further, in S3, a mathematical model of the temperature field between the dry reactor and the ambient air fluid is constructed, and the following steady-state temperature control equation is established according to the theory of heat transfer:
in the formula: k is the thermal conductivity of the encapsulating material; q is the heat generation rate per unit volume; t issIs the solid surface temperature; t isfIs the fluid temperature; h is a heat dissipation coefficient; epsilon is the thermal radiance; σ is Boltzmann constant, which is 5.67 x 10-8W (m 2. K4); gamma-shaped3The reactor solid and air interface; gamma-shaped2Is a periodic symmetry plane;
the heat source of the enclosure is determined by the heat generation rate of the current in the enclosure:
p is the loss of the reactor envelope, and V is the volume of the envelope;
the governing equations for the fluid include mass continuity equations, momentum conservation equations, and mass conservation equations. In the analysis, considering the ambient air fluid as an incompressible viscous fluid, the fluid is in a steady flow state, and the mass conservation equation can be expressed as:
the conservation of momentum equation can be expressed as:
the energy conservation equation is:
wherein ρ is an air density; u is the fluid velocity vector; u, v and w are coordinate components of the velocity vector in the directions of coordinate axes x, y and z, and mu is an air motion viscosity coefficient; p is air pressure; c. CpIs the specific heat capacity of air; λ is the thermal conductivity of air; su、Sv、SwBeing a generalized source term of the hydrodynamic equation, S is the direction of gravity vertically downward along the z-axisu＝Sv＝0，Sw＝ρg；STA fluid viscous dissipation term.
Further, in S1, the optical fiber is wound around the surface of the reactor winding and is poured with epoxy resin together with the winding, and the epoxy resin plays a role in fixing and insulating at the same time.
Furthermore, the signal acquisition unit is a high-speed data acquisition card, and the denoising processing unit and the temperature demodulation unit are realized by computer software.
Further, to ensure the fluid equation is closed, the air also needs to satisfy the gas equation of state: ρ ═ f (p, T)f)。
In the conventional detection of the dry-type reactor, a plurality of external temperature sensors are generally adopted for distribution measurement, the detection method has the advantages of low cost and convenience in installation, and can meet detection requirements to a certain extent, so that the detection method is widely applied, for example, a dry-type reactor temperature detection system disclosed in patent document with publication number CN 103674293 a detects the temperature of the dry-type reactor through a temperature detection device built in the dry-type reactor, and sends the detected temperature value to a monitoring terminal through a data transmission device. And when the monitoring terminal determines that the temperature in the dry-type reactor exceeds a preset temperature value, outputting an alarm signal.
The detection system disclosed in the document adopts a temperature sensor dispersion measurement method, can realize real-time detection and alarm, but because the temperature sensor is not scientifically arranged, the problem of large detection error is easily caused, and the heating point of the reactor cannot be found in time, therefore, the patent with publication number of CN 104266603B discloses a device for detecting the temperature and the strain of the dry-type air-core reactor on site, which is formed by connecting a Bragg fiber grating sensor (3) with an optical coupler (4), and connecting the optical coupler (4) with a fiber grating demodulator (5) through jumping fibers; the optical coupler (4) is formed by sequentially connecting a signal input channel (9), a programmable logic controller unit and a signal output channel (10).
The detection device disclosed by the patent adopts the optical fiber sensor to perform distributed detection, can detect the temperature and the strain quantity on the surface of the drawing rod on line, reflects the working condition of the reactor during working, further reasonably switches the reactor, solves the problem that the dry-type hollow reactor is frequently burnt, and has the advantages of safety and economy. However, finite element simulation is not performed on the multi-physical field of the dry-type reactor, so that the measurement cannot be performed according to the normal operation and the local heating condition of the dry-type reactor, thereby causing a problem of detection delay and affecting the safe operation of the dry-type reactor.
In addition, the research of the domestic distributed optical fiber temperature measurement system is started in 1987, and the research is carried out successively by a plurality of colleges and scientific research units such as China metering university, Zhejiang university and China school. The Chinese measurement university intensively studies a plurality of problems of the distributed optical fiber temperature sensor in 1993, successfully develops a model FGC _ W1 distributed optical fiber Raman temperature measurement system in the second year, and achieves the measurement distance of 30km and the temperature resolution of 0.1 ℃ through gradual development. The university of electronic science and technology mainly carries out a series of researches on a distributed optical fiber Raman temperature measurement system on the basis of a demodulation algorithm, provides a cyclic demodulation method for demodulating anti-Stokes light by using recently measured backward Rayleigh scattering light, a region calibration method for dividing, judging and re-demodulating a measured temperature range, a symmetric demodulation method for demodulating anti-Stokes scattering light time domain reflection signals by using Rayleigh scattering light time domain reflection signals and a Raman temperature measurement system with an optical amplifier and an optical fiber ring, and realizes the measurement error of +/-0.03 ℃ and the spatial resolution of 1m through experiments. The Qinghua university makes related exploration on a data processing method and a light source, and provides a demodulation algorithm for processing data by using a deconvolution algorithm so as to obtain high spatial resolution and a Raman temperature measurement system for realizing high spatial resolution or high temperature resolution by using a variable pulse width light source. The domestic company mainly has Ningbo Zhendong photoelectricity, Hangzhou Europe memory photoelectricity, Nanjing industry auspicious science and technology and the like, the detection distance of related products is below 15km, the spatial resolution is 1m, the temperature resolution is 0.1 ℃, and the method has larger gap compared with similar products abroad. Based on this, it is not easy for the existing personnel to think and realize that the distributed optical fiber temperature measurement system is applied to the dry-type reactor to accurately detect the dry-type reactor.
Compared with the prior art, the invention has the following beneficial effects:
the distributed optical fiber sensor is adopted, temperature can be continuously measured in a space range, the distributed optical fiber sensor has the advantages of good insulating property, electromagnetic interference resistance, high temperature resistance and the like, sensing optical fibers can be arranged according to the characteristics of temperature measurement places, the sensing optical fibers only need to be pasted on the surface of the cladding of the reactor, and the structure of equipment is prevented from being greatly changed.
The invention analyzes the physical process of the dry type reactor in operation, including the flow of cooling media such as magnetic field, electric field and heat transfer and air. And on the basis of analysis, the modeling of the operation state of the dry-type reactor is completed, the dry-type reactor is simulated, the temperature distribution condition and the heating point distribution condition of the dry-type reactor in the normal operation process are obtained, and a foundation is provided for accurate detection.
The invention researches the basic theory of Raman scattering in the optical fiber and the sensing mechanism of a distributed optical fiber temperature sensing system based on the Raman scattering principle, and demodulates the main technical indexes and temperature signals; a set of distributed optical fiber temperature sensing system based on the spontaneous Raman scattering principle is designed, backward spontaneous Raman scattering optical signals are amplified and denoised, and system detection precision is improved.
The invention can detect the temperature distributed along the direction of the optical fiber by utilizing the Raman scattering principle, and can detect the temperature distribution condition of the reactor by analyzing the change of the Stokes signal and the anti-Stokes signal. The basic principle of detecting the temperature of the reactor based on the distributed optical fiber sensing technology is that Raman anti-Stokes scattered light is used as demodulation signal light, Stokes scattered light is used as reference signal light, errors caused by bending of an optical fiber, gain change of a photoelectric detector and the like are eliminated through the ratio of the anti-Stokes light intensity to the Stokes light intensity, the temperature information of the reactor is obtained through demodulation of Raman scattering signals, the operation is stable, and the measurement accuracy is high.
The invention can accurately detect the temperature state of the dry-type reactor, is beneficial to judging the state of the reactor in time, finds potential safety hazards in the reactor in advance, avoids serious loss caused by overheating faults, and has wide market value and application prospect.
Drawings
Fig. 1 is a connection block diagram of a reactor temperature detection system based on raman scattering in a second embodiment of the present invention;
FIG. 2 is a spectrum of a scattered light in the second embodiment of the present invention;
fig. 3 is a schematic diagram of optical time domain reflection according to a second embodiment of the present invention.
Detailed Description
In order to better understand the present invention, the following examples are further provided to clearly illustrate the contents of the present invention, but the contents of the present invention are not limited to the following examples. In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details.
Example one
As shown in fig. 1, a method for detecting a temperature of a dry-type reactor based on distributed optical fiber sensing includes the following steps: s1: distributing a distributed optical fiber sensor on the dry-type reactor;
s2: constructing a magnetic field-circuit coupling model of the dry-type reactor, and obtaining the temperature distribution condition and the heating point distribution condition of the dry-type reactor in the normal operation process;
s3: constructing a mathematical model of a temperature field of the dry reactor and ambient air fluid, obtaining an error between the optical fiber measurement temperature and the dry reactor encapsulation temperature, and constructing a temperature compensation algorithm;
s4: the distributed optical fiber sensor is connected with a reactor temperature detection system based on Raman scattering through a wavelength division multiplexer, the reactor temperature detection system based on Raman scattering is used for collecting and processing signals of the distributed optical fiber sensor, and processed dry-type reactor temperature information is displayed.
Example two
A dry-type reactor temperature detection method based on distributed optical fiber sensing comprises the following steps:
s1: distributing a distributed optical fiber sensor on the dry-type reactor;
s2: constructing a magnetic field-circuit coupling model of the dry-type reactor, and obtaining the temperature distribution condition and the heating point distribution condition of the dry-type reactor in the normal operation process;
s3: constructing a mathematical model of a temperature field of the dry reactor and ambient air fluid, obtaining an error between the optical fiber measurement temperature and the dry reactor encapsulation temperature, and constructing a temperature compensation algorithm;
s4: the distributed optical fiber sensor is connected with a reactor temperature detection system based on Raman scattering through a wavelength division multiplexer, the reactor temperature detection system based on Raman scattering is used for collecting and processing signals of the distributed optical fiber sensor, and processed dry-type reactor temperature information is displayed.
The embodiment of the invention is different from the first embodiment in that: the distributed optical fiber sensor comprises an optical pulse laser, a photoelectric converter, a signal amplifier and a computer, wherein the pulse laser is in serial port communication with the computer, and the computer controls the pulse laser to emit optical pulses to enter the sensing optical fiber.
As shown in fig. 1, the reactor temperature detection system based on raman scattering includes a signal acquisition unit, a denoising processing unit, a storage unit, a temperature demodulation unit, and a display unit, the wavelength division multiplexer divides the acquired light into anti-stokes light and stokes light, respectively transmits the anti-stokes light and the stokes light to the signal acquisition unit, the denoising processing unit, and a first storage unit after being processed by the photoelectric conversion amplification unit, respectively, and the two first storage units are all connected with the temperature demodulation unit, the second storage unit, and the display unit in sequence.
The signal acquisition unit is a high-speed data acquisition card, and the denoising processing unit and the temperature demodulation unit are realized by computer software.
The backscattering effect in the optical fiber is an important theoretical basis of the distributed optical fiber sensing technology, when pulsed light emitted by a laser is injected into the optical fiber from the starting end of the optical fiber, due to the nonuniformity of a medium, the light in the medium directionally propagates along the direction of light propagation on one hand, and scattered light towards other directions is emitted on the other hand, wherein the backscattering light is the backscattering light which is opposite to the incident direction in the scattering direction.
As shown in fig. 2, raman scattering results from the interaction of photons within the fiber with the fiber molecules, which includes two types of scattered light, one is that photons in the fiber convert light energy into thermal vibrations of the fiber molecules, such that the wavelength of the scattered light is longer than the light source wavelength, called raman Stokes light (Stokes); the other is that the fiber molecules in the fiber convert the thermal vibration of the fiber molecules into the light energy of photons, so that the wavelength of the scattered light is shorter than the wavelength of the light source, which is called Raman Anti-Stokes light.
An Optical Time Domain Reflectometer (OTDR) is a theoretical basis for a distributed optical fiber raman temperature measurement system to combine temperature information and position information, and mainly detects the length of an optical fiber and a fault point by measuring and demodulating backscattered light, and determines the specific position of an event point in the optical fiber.
As shown in fig. 3, pulsed light emitted by a pulsed light source enters an optical fiber from the initial end of the optical fiber, reaches a scattering point after a time t/2, generates scattering by interaction between photons and optical fiber molecules at the scattering point, and the distance from the initial point to the scattering point is set as L. The backward scattering light returns to the starting end of the optical fiber along the direction opposite to the incident light, the passing distance is L, the time is t/2, and the relation between t and L is as follows:
where c is the propagation speed of light in vacuum and n is the refractive index of the core of the optical fiber.
Therefore, under the condition that the parameters c and n are known, the distance L from the scattering point to the starting end of the optical fiber can be obtained by measuring the time t required by the Raman backscattered light from the injection of the pulse light into the optical fiber to the returning to the starting end of the optical fiber, and the ambient temperature at the distance L from the light source can be demodulated by combining the method for demodulating the temperature through the light intensity of the Raman scattered light described in the previous section. The distributed measurement of the environmental temperature of the whole optical fiber can be realized by measuring the intensity of scattered light at different time t, but in order to avoid the phenomenon that the scattered light in the optical fiber generates aliasing and affects the demodulation of the temperature, a certain time is required to be separated between adjacent pulses, so that the system is not interfered by other pulses when receiving the scattered light of one pulse.
EXAMPLE III
The dry-type reactor temperature detection method based on distributed optical fiber sensing of the embodiment of the invention is different from the first embodiment and the second embodiment in that: and S1, winding the optical fiber on the surface of the reactor winding, and pouring the optical fiber and the reactor winding together with the winding by using epoxy resin, wherein the epoxy resin plays a role in fixing and insulating at the same time.
In S2, a magnetic field-circuit coupling model of the dry reactor is constructed, and modeling is performed by using a cylindrical coordinate system: under the cylindrical coordinate system, the control equation of the magnetic field is
In the formula: r is the radial distance under the cylindrical coordinate system; z is the axial distance; a is a magnetic vector bit; μ 0 is the magnetic permeability; j is the source current density.
The constraint equation of the ith layer coil by an external circuit is as follows:
wherein U is an external confinement voltage, Ri、ψi、Ni、Ii、SiThe resistance, flux linkage, number of turns, current, and cross-sectional area of the i-th layer coil are respectively.
The four equations are combined to establish a field-path coupling finite element equation, the current value and the vector magnetic potential of each layer of encapsulation can be obtained, and the magnetic induction intensity can be obtained from the vector magnetic potential
B＝▽×A
The i-th layer loss Pi of the winding mainly comprises resistive loss Pri and eddy current loss Pei, wherein the i-th layer of the winding has loss of
In the formula: gamma is the resistivity of the wire; ω is the angular frequency of the applied excitation; diThe wire diameter of the ith turn of wire; i isiThe radius of each turn of wire; b isiThe magnetic induction intensity at the center of the ith turn of the wire.
In S3, a mathematical model of the temperature field of the dry reactor and the ambient air fluid is constructed, and the following steady-state temperature control equation is established according to the theory of heat transfer:
in the formula: k is the thermal conductivity of the encapsulating material; q is the heat generation rate per unit volume; t issIs the solid surface temperature; t isfIs the fluid temperature; h is a heat dissipation coefficient; epsilon is the thermal radiance; σ is Boltzmann constant, which is 5.67 x 10-8W (m 2. K4); gamma-shaped3The reactor solid and air interface; gamma-shaped2Is a periodic symmetry plane;
the heat source of the enclosure is determined by the heat generation rate of the current in the enclosure:
p is the loss of the reactor envelope, and V is the volume of the envelope;
the governing equations for the fluid include mass continuity equations, momentum conservation equations, and mass conservation equations. In the analysis, considering the ambient air fluid as an incompressible viscous fluid, the fluid is in a steady flow state, and the mass conservation equation can be expressed as:
▽·(ρu)＝0
the conservation of momentum equation can be expressed as:
the energy conservation equation is:
wherein ρ is an air density; u is the fluid velocity vector; u, v and w are coordinate components of the velocity vector in the directions of coordinate axes x, y and z, and mu is an air motion viscosity coefficient; p is air pressure; c. CpIs the specific heat capacity of air; λ is the thermal conductivity of air; su、Sv、SwBeing a generalized source term of the hydrodynamic equation, S is the direction of gravity vertically downward along the z-axisu＝Sv＝0，Sw＝ρg；STA fluid viscous dissipation term.
To ensure the fluid equation is closed, the air also needs to satisfy the gas equation of state: ρ ═ f (p, T)f)。
The simulation of the temperature field of the dry reactor mainly relates to an electric field, a magnetic field and a flow field, the loss caused by the fact that the main heat source is an electromagnetic field comprises magnetic field eddy current loss and the heat effect of current, and the main heat dissipation mode is natural convection heat dissipation of air and heat radiation of a winding to the outside. The multi-field coupling calculation of the dry type hollow parallel reactor adopts an indirect coupling method of load transfer: because the conductor resistivity is related to the temperature, a two-dimensional magnetic field-circuit coupling model under the constraint condition of the voltage of an external circuit port needs to be established firstly, and the current and the loss in each encapsulation of the reactor at the initial temperature are calculated in an electromagnetic field; and then, establishing a reactor three-dimensional fluid-temperature field finite element calculation model according to a fluid dynamics theory and a heat transfer theory, and applying the winding loss obtained by electromagnetic field analysis to the fluid-temperature field finite element model as a load to calculate the temperature field and the flow field distribution of the reactor body. And comparing the temperature values obtained by the two calculations, setting the temperature convergence criterion to be 3%, and if the temperature convergence criterion does not meet the requirement, repeating the iterative calculation until the temperature converges.
Finally, the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting, and other modifications or equivalent substitutions made by the technical solutions of the present invention by those of ordinary skill in the art should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.
Claims (8)
1. A dry-type reactor temperature detection method based on distributed optical fiber sensing is characterized by comprising the following steps:
s1: distributing a distributed optical fiber sensor on the dry-type reactor;
s2: constructing a magnetic field-circuit coupling model of the dry-type reactor, and obtaining the temperature distribution condition and the heating point distribution condition of the dry-type reactor in the normal operation process;
s3: constructing a mathematical model of a temperature field of the dry reactor and ambient air fluid, obtaining an error between the optical fiber measurement temperature and the dry reactor encapsulation temperature, and constructing a temperature compensation algorithm;
s4: the distributed optical fiber sensor is connected with a reactor temperature detection system based on Raman scattering through a wavelength division multiplexer, the reactor temperature detection system based on Raman scattering is used for collecting and processing signals of the distributed optical fiber sensor, and processed dry-type reactor temperature information is displayed.
2. The dry reactor temperature detection method based on distributed optical fiber sensing as claimed in claim 1, wherein: the distributed optical fiber sensor comprises an optical pulse laser, a photoelectric converter, a signal amplifier and a computer, wherein the pulse laser is in serial port communication with the computer, and the computer controls the pulse laser to emit optical pulses to enter the sensing optical fiber.
3. The dry reactor temperature detection method based on distributed optical fiber sensing as claimed in claim 2, wherein: the reactor temperature detection system based on Raman scattering comprises a signal acquisition unit, a denoising processing unit, a storage unit, a temperature demodulation unit and a display unit, wherein the wavelength division multiplexer divides acquired light into anti-Stokes light and Stokes light, and the anti-Stokes light and the Stokes light are respectively subjected to photoelectric conversion and amplification and are respectively and sequentially transmitted to the signal acquisition unit, the denoising processing unit, the first storage unit, the temperature demodulation unit, the second storage unit and the display unit.
4. The dry reactor temperature detection method based on distributed optical fiber sensing as claimed in claim 1, wherein: in S2, a magnetic field-circuit coupling model of the dry reactor is constructed, and modeling is performed by using a cylindrical coordinate system: under the cylindrical coordinate system, the control equation of the magnetic field is
In the formula: r is the radial distance under the cylindrical coordinate system; z is the axial distance; a is a magnetic vector bit; μ 0 is the magnetic permeability; j is the source current density.
The constraint equation of the ith layer coil by an external circuit is as follows:
wherein U is an external confinement voltage, Ri、ψi、Ni、Ii、SiThe resistance, flux linkage, number of turns, current, and cross-sectional area of the i-th layer coil are respectively.
The four equations are combined to establish a field-path coupling finite element equation, the current value and the vector magnetic potential of each layer of encapsulation can be obtained, and the magnetic induction intensity can be obtained from the vector magnetic potential
B＝▽×A
The i-th layer loss Pi of the winding mainly comprises resistive loss Pri and eddy current loss Pei, wherein the i-th layer of the winding has loss of
In the formula: gamma is the resistivity of the wire; ω is the angular frequency of the applied excitation; diThe wire diameter of the ith turn of wire; i isiThe radius of each turn of wire; b isiThe magnetic induction intensity at the center of the ith turn of the wire.
5. The dry reactor temperature detection method based on distributed optical fiber sensing as claimed in claim 1, wherein: in S3, a mathematical model of the temperature field of the dry reactor and the ambient air fluid is constructed, and the following steady-state temperature control equation is established according to the theory of heat transfer:
in the formula: k is the thermal conductivity of the encapsulating material; q is the heat generation rate per unit volume; t issIs the solid surface temperature; t isfIs the fluid temperature; h is a heat dissipation coefficient; epsilon is the thermal radiance; σ is Boltzmann constant, which is 5.67 x 10-8W (m 2. K4); gamma-shaped3The reactor solid and air interface; gamma-shaped2Is a periodic symmetry plane;
the heat source of the enclosure is determined by the heat generation rate of the current in the enclosure:
p is the loss of the reactor envelope, and V is the volume of the envelope;
the governing equations for the fluid include mass continuity equations, momentum conservation equations, and mass conservation equations. In the analysis, considering the ambient air fluid as an incompressible viscous fluid, the fluid is in a steady flow state, and the mass conservation equation can be expressed as:
▽·(ρu)＝0
the conservation of momentum equation can be expressed as:
the energy conservation equation is:
wherein ρ is an air density; u is the fluid velocity vector; u, v and w are coordinate components of the velocity vector in the directions of coordinate axes x, y and z, and mu is an air motion viscosity coefficient; p is air pressure; c. CpIs the specific heat capacity of air; λ is the thermal conductivity of air; su、Sv、SwBeing a generalized source term of the hydrodynamic equation, S is the direction of gravity vertically downward along the z-axisu＝Sv＝0，Sw＝ρg；STA fluid viscous dissipation term.
6. The dry reactor temperature detection method based on distributed optical fiber sensing as claimed in claim 1, wherein: and S1, winding the optical fiber on the surface of the reactor winding, and pouring the optical fiber and the reactor winding together with the winding by using epoxy resin, wherein the epoxy resin plays a role in fixing and insulating at the same time.
7. The dry reactor temperature detection method based on distributed optical fiber sensing as claimed in claim 3, wherein: the signal acquisition unit is a high-speed data acquisition card, and the denoising processing unit and the temperature demodulation unit are realized by computer software.
8. The dry reactor temperature detection method based on distributed optical fiber sensing as claimed in claim 5, wherein: to ensure the fluid equation is closed, the air also needs to satisfy the gas equation of state: ρ ═ f (p, T)f)。
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114167218A (en) * | 2021-12-09 | 2022-03-11 | 国网河南省电力公司南阳供电公司 | Dry-type reactor fault early warning system based on distributed detection |
| CN115664524A (en) * | 2022-10-25 | 2023-01-31 | 中国电子科技集团公司第三十八研究所 | Phase-stabilized radio frequency optical transmission method and system based on distributed Raman temperature measurement |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160027537A1 (en) * | 2014-07-23 | 2016-01-28 | Ge-Hitachi Nuclear Energy Americas Llc | Fiber optic temperature sensing system and method utilizing brillouin scattering for large, well-ventilated spaces |
| CN105352625A (en) * | 2015-10-21 | 2016-02-24 | 国家电网公司 | Temperature measurement system for dry-type hollow reactor |
| CN107687908A (en) * | 2017-08-24 | 2018-02-13 | 重庆大学 | A kind of method and system for the temperature rise focus and temperature monitoring for obtaining dry-type air-core reactor |
| CN107871037A (en) * | 2017-10-26 | 2018-04-03 | 中国南方电网有限责任公司超高压输电公司广州局 | A kind of 35kV dry reactors internal temperature evaluation method |
-
2020
- 2020-01-10 CN CN202010024205.9A patent/CN111157142A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160027537A1 (en) * | 2014-07-23 | 2016-01-28 | Ge-Hitachi Nuclear Energy Americas Llc | Fiber optic temperature sensing system and method utilizing brillouin scattering for large, well-ventilated spaces |
| CN105352625A (en) * | 2015-10-21 | 2016-02-24 | 国家电网公司 | Temperature measurement system for dry-type hollow reactor |
| CN107687908A (en) * | 2017-08-24 | 2018-02-13 | 重庆大学 | A kind of method and system for the temperature rise focus and temperature monitoring for obtaining dry-type air-core reactor |
| CN107871037A (en) * | 2017-10-26 | 2018-04-03 | 中国南方电网有限责任公司超高压输电公司广州局 | A kind of 35kV dry reactors internal temperature evaluation method |
Non-Patent Citations (1)
| Title |
|---|
| 陈嵘等: "干式空心并联电抗器电磁–流体–温度场耦合计算与分析", 《高电压技术》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114167218A (en) * | 2021-12-09 | 2022-03-11 | 国网河南省电力公司南阳供电公司 | Dry-type reactor fault early warning system based on distributed detection |
| CN115664524A (en) * | 2022-10-25 | 2023-01-31 | 中国电子科技集团公司第三十八研究所 | Phase-stabilized radio frequency optical transmission method and system based on distributed Raman temperature measurement |
| CN115664524B (en) * | 2022-10-25 | 2024-08-06 | 中国电子科技集团公司第三十八研究所 | Stable-phase radio frequency optical transmission method and system based on distributed Raman temperature measurement |
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