CN103913252A - High-voltage direct current power transmission system grounding electrode temperature field monitoring system and method - Google Patents
High-voltage direct current power transmission system grounding electrode temperature field monitoring system and method Download PDFInfo
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- CN103913252A CN103913252A CN201410098760.0A CN201410098760A CN103913252A CN 103913252 A CN103913252 A CN 103913252A CN 201410098760 A CN201410098760 A CN 201410098760A CN 103913252 A CN103913252 A CN 103913252A
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Abstract
The invention provides a high-voltage direct current power transmission system grounding electrode temperature field monitoring system and method. According to the system, optical fibers are arranged along a grounding electrode; a Brillouin distributed optical fiber sensor is connected with the optical fibers and used for sending lasers to the optical fibers, Brillouin scattering light generated in the optical fibers is detected and is analyzed and processed based on the Brillouin scattering light principle, and temperature distribution data of the optical fibers are acquired; a grounding electrode temperature field monitoring host is used for determining temperature field distribution conditions of the grounding electrode according to the temperature distribution data of the optical fibers. By means of the system and method, power supply equipment does not need to be provided for the electrode address of the grounding electrode, and collected data loss caused by the lack of power supplies is avoided; because the optical fibers are arrayed along the grounding electrode, temperature collecting points are denser, the overall temperature field of the grounding electrode can be covered with the temperature collecting points which are denser, and true grounding-electrode temperature field conditions can be restored effectively.
Description
Technical field
The present invention relates to high voltage dc transmission technology field, particularly, relate to a kind of System for HVDC System Earth Pole temperature field monitoring system and method.
Background technology
China's energy and load center distributed pole on region is unbalanced, has determined China's energy source remote distance, extensive mobile inexorable trend.HVDC(High-Voltage Direct Current, D.C. high voltage transmission), advantage that fed distance far away large with its power transmission capacity, in flowing, the energy there is irreplaceable status.
High voltage dc transmission technology is different from ac transmission aspect a lot, has it self intrinsic feature and technical requirement, and earthing pole designing technique is exactly an example wherein.HVDC (High Voltage Direct Current) transmission system is that working earthing and safeguard protection ground connection are separated, and working earthing is referred to as earthing pole.Earthing pole is the important component part of the current conversion station metal ground return circuit method of operation, plays an important role DC transmission system is in service: the one, directly for a long time for system transmits electric power, improve system reliability of operation; The 2nd, clamp down on current conversion station neutral point current potential, avoid the two poles of the earth voltage-to-ground imbalance and infringement equipment.
The HVDC (High Voltage Direct Current) transmission system having put into operation mostly at present is both-end DC transmission system, is characterized in only having a sending end current conversion station and a receiving end current conversion station.In both-end DC transmission system, earthing pole can be straight-flow system transmission DC current constantly, thereby forms the cocurrent flow loop of sending end current conversion station, aerial condutor, receiving end current conversion station and the earth composition, ensures to carry constantly DC power.The DC current of sending end current conversion station causes by aerial condutor on the equipment of earth electrode field center, by flow guide system feed-in the earth, then flows to receiving end current conversion station earthing pole by the earth, thereby completes ground return circuit.
Figure 1 shows that earth electrode diversion system forms schematic diagram, current conversion station is drawn DC current to be connected to terminal tower by aerial condutor, at terminal tower hollow wire, DC current is drawn and is connected to water conservancy diversion lead-in wire, by water conservancy diversion lead-in wire, DC current is drawn to be connected to again and be embedded in the feed cable of terminal tower under peripherally, finally DC current is caused on earthing pole and be transferred to the earth by feed cable.
At present common earthing pole can be divided into the types such as many annulars, vertical shape, ellipse, star according to the difference of shape.As shown in Figure 2, vertical shape earthing pole is generally vertically embedded in underground feed rod by some and forms, and each root feed rod is all connected with feed cable, for the DC current of feed cable transmission is introduced to the earth; As shown in Figure 3, many annulars earthing pole is generally made up of in one heart two annular coke tracks underground and parallel to the ground shallow embedding, and coke track is connected with feed cable, for the DC current of feed cable transmission is introduced to the earth.
Flow into the earth current of the earth by earthing pole, the distribution on earthing pole is inhomogeneous.Generally speaking, the end overflow maximum of earthing pole, middle part is minimum, and its difference can reach several times.This distribution has caused earthing pole utilization factor low, the overheated and premature corrosion of partial portion, the problems such as surface potential skewness.Now, in order to save land used and to reduce construction costs, generally adopt multiple DC transmission system to share the mode of an earthing pole.But for the mode of One Common Earthing Electrode, in the time adopting one pole the earth or bipolar off-center operation mode in the straight-flow system of One Common Earthing Electrode, the large electric current earthing pole of flowing through can cause earthing pole soil heating around, the soil moisture is raise, when serious, may affect the normal work of earthed system, if earthing pole is worked in the environment of excess Temperature, occur that the probability burning will increase greatly, and will produce more serious consequence.The south bridge direct current grounding pole of the Shanghai end of reaching the standard grade as 500kV DC transmission system Pueraria lobota, Zeng Yinwei distribution of current is inhomogeneous and have an accident, and earthing pole and leading cable are burnt.Therefore can safe operation in order to ensure earthing pole, during day-to-day operation, need to grasp at any time the temperature conditions in earth electrode field region.
Because earthing pole is in underground, the monitor well that prior art general using is arranged at earth electrode field region obtains the temperature information at earthing pole scene, its concrete scheme is: the place at feed cable access point arranges monitor well, monitor well adopts pvc pipe, monitor well is vertically installed in earthing pole top or close earthing pole both sides, dew is opened in bottom, upper end flushes with ground, near the temperature diverse location place of monitor well mounting temperature sensor detects relevant position, and by temperature sensor, the temperature data of collection is radioed to distance host.But this scheme has following shortcoming:
1, be subject to the restriction of chosen position, the temperature sensor quantity etc. of monitor well, the temperature information collecting can not cover the bulk temperature field of earthing pole, can not effectively restore real earthing pole temperature field situation;
2, want Real-time Collection temperature information, temperature sensor must have sufficient power supply, but because earth electrode field is generally chosen at remote spacious location, limit the supply of power supply, even if some equipment has adopted wind light mutual complementing mode to power, also exist electricity shortage situation to a certain degree to occur, cause the temperature information detecting to be lost;
3, wireless transmission temperature acquisition data are higher to the performance requirement of equipment, and transmission range is shorter, poor anti jamming capability.
The present invention is under National 863 planning item fund (2012AA050209) is subsidized, and has proposed a kind of System for HVDC System Earth Pole temperature field monitoring system and method.
Summary of the invention
The fundamental purpose of the embodiment of the present invention is to provide a kind of System for HVDC System Earth Pole temperature field monitoring system and method, and to solve, monitoring technique monitoring point, existing earthing pole temperature field is complete, monitored density is poor, need to provide the problem such as power supply and easy obliterated data at earth electrode field.
To achieve these goals, the embodiment of the present invention provides a kind of System for HVDC System Earth Pole temperature field monitoring system, comprising: optical fiber, brillouin distributed optical fiber sensing device and earthing pole temperature field monitoring main frame, wherein,
Described optical fiber is laid along earthing pole;
Described brillouin distributed optical fiber sensing device connects described optical fiber, for sending laser to described optical fiber, detect the Brillouin scattering producing in described optical fiber, and based on Brillouin scattering principle, described Brillouin scattering is carried out to analyzing and processing, obtain the temperature profile data of described optical fiber;
Monitoring main frame in described earthing pole temperature field is for determining the temperature field distribution situation of described earthing pole according to the temperature profile data of described optical fiber.
Accordingly, the present invention also provides a kind of System for HVDC System Earth Pole temperature field monitoring method, comprising:
Along earthing pole laying optical fiber;
Send laser to described optical fiber, detect the Brillouin scattering producing in described optical fiber, and based on Brillouin scattering principle, described Brillouin scattering is carried out to analyzing and processing, obtain the temperature profile data of described optical fiber;
Determine the temperature field distribution situation of described earthing pole according to the temperature profile data of described optical fiber.
By means of technique scheme, the temperature of the each position of optical fiber that the present invention utilizes the Fibre Optical Communication Technology of Brillouin scattering principle to obtain to lay along earthing pole, and then the temperature field distribution situation of definite earthing pole, than prior art, the present invention has avoided providing power-supply device at earth electrode field, avoid losing the generation of problem because power supply deficiency causes image data, because optical fiber is to lay along earthing pole, its temperature acquisition is put crypto set more and can be covered the bulk temperature field of earthing pole, can effectively restore real earthing pole temperature field situation.
Brief description of the drawings
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, below the accompanying drawing of required use during embodiment is described is briefly described, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is that the earth electrode diversion system that background technology of the present invention provides forms schematic diagram;
Fig. 2 is the vertical shape earthing pole structural representation that background technology of the present invention provides;
Fig. 3 is many annulars earthing pole structural representation that background technology of the present invention provides;
Fig. 4 is System for HVDC System Earth Pole provided by the invention temperature field monitoring system structural representation;
Fig. 5 is that a kind of optical fiber for two annular earthing poles provided by the invention is laid mode schematic diagram;
Fig. 6 is that the another kind of optical fiber for two annular earthing poles provided by the invention is laid mode schematic diagram;
Fig. 7 is that a kind of optical fiber for vertical shape earthing pole provided by the invention is laid mode schematic diagram;
Fig. 8 is the principle of work schematic diagram of the BOTDA sensor of the single laser instrument scheme of employing provided by the invention;
Fig. 9 is that earthing pole provided by the invention temperature field monitoring main frame adopts many wavelet transformations to obtain the schematic flow sheet of earthing pole temperature field distribution situation;
Figure 10 is that the optical fiber that the specific embodiment of the invention provides is laid mode schematic diagram;
Figure 11 is the particular flow sheet of System for HVDC System Earth Pole provided by the invention temperature field monitoring method.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiment.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.
The invention provides a kind of System for HVDC System Earth Pole temperature field monitoring system, as shown in Figure 4, this system comprises: optical fiber 41, brillouin distributed optical fiber sensing device 42 and earthing pole temperature field monitoring main frame 43.Wherein, optical fiber 41 is laid along earthing pole 40; Brillouin distributed optical fiber sensing device 42 connects optical fiber 41, for sending laser to optical fiber 41, the Brillouin scattering producing in detection fiber 41, and based on Brillouin scattering principle, Brillouin scattering is carried out to analyzing and processing, obtain the temperature profile data of optical fiber 41; Earthing pole temperature field monitoring main frame 43 is for determining the temperature field distribution situation of earthing pole 40 according to the temperature profile data of optical fiber 41.
The present invention adopts along earthing pole laying optical fiber, and utilizes Distributed Optical Fiber Sensing Techniques based on Brillouin scattering principle to obtain on optical fiber temperature everywhere, and then obtains the temperature field distribution situation of earthing pole.Because optical fiber itself does not need power supply, therefore the present invention has saved the trouble that power-supply device is installed at earth electrode field, can avoid because of the not enough problem that causes image data to be lost of power supply simultaneously; And because optical fiber is to lay along earthing pole, therefore temperature acquisition is put crypto set more and can be covered the bulk temperature field of earthing pole, can effectively restore real earthing pole temperature field situation; In addition, utilize the advantages such as long transmission distance, the antijamming capability of optical fiber sensing technology be strong, the present invention has improved the ability of earthing pole temperature data remote transmission, is more conducive to the ruuning situation of remote monitoring earthing pole.
In order to ensure the bulk temperature field distribution situation that can obtain earthing pole, the present invention need to make each position of optical fiber cloth and earthing pole, and the concrete laying mode of optical fiber need to change along with the shape difference of earthing pole.
In a kind of preferred embodiment, if the very two annulars of ground connection, earthing pole is made up of in underground same intracardiac ring coke track, outer shroud coke track shallow embedding, and optical fiber is laid along interior ring coke track, the outer shroud coke track of earthing pole.
Preferably the invention provides following a kind of optical fiber and lay mode: as shown in Figure 5, optical fiber is accessed by terminal tower, is then divided into two parts; Wherein a part is as shown in the dotted arrow in Fig. 5, be linked into a certain monitor well of interior ring coke track by terminal tower, then lay along interior ring coke track counterclockwise, laying length is 1/8 of inner circumference length, the directions of rays then connecting and composing along the center of circle and current loca is deployed to outer shroud coke track, lay along outer shroud coke track again, laying length is 1/8 of outer shroud girth, and then turn back to interior ring along the directions of rays that the center of circle and current loca connect and compose, the rest may be inferred, until intersect 1/2 of the complete interior ring of cloth and outer shroud; Similarly, another part is as shown in the solid arrow in Fig. 5, be linked into a certain monitor well of outer shroud coke track by terminal tower, then lay along outer shroud coke track counterclockwise, laying length is 1/8 of outer shroud girth, the directions of rays then connecting and composing along the center of circle and current loca is deployed to interior ring coke track, lay along interior ring coke track again, laying length is 1/8 of inner circumference length, and then turn back to outer shroud along the directions of rays that the center of circle and current loca connect and compose, the rest may be inferred, until intersect 1/2 of the complete interior ring of cloth and outer shroud.The advantage that this optical fiber is laid mode is to take into account along the circumferential Temperature Distribution of inner and outer rings direction and along the radial temperature profile of radial direction simultaneously, and optical fiber lays not only around inside and outside two loop orbits but also do not repeat, and has saved optical fiber deployment cost.
Preferably, the present invention also provides following a kind of optical fiber to lay mode: as shown in Figure 6, laying as shown in Figure 5 on the basis of mode, also at the depth direction laying optical fiber perpendicular to earthing pole place plane, and (this plane is at least one in the plane that is setpoint distance apart from earthing pole place plane, below this plane is become to sample plane) interior laying optical fiber, wherein the laying of the optical fiber in each sample plane mode is all consistent with the laying mode shown in Fig. 5.The advantage that this optical fiber is laid mode is to have considered the temperature conduction factor of earthing pole to soil, takes into account the temperature field distribution situation in depth direction.
In another kind of preferred embodiment, if the very vertical shape of ground connection, earthing pole is vertically embedded in underground feed rod by some and forms, and optical fiber is laid along each feed rod of earthing pole.
Preferably, the invention provides following a kind of optical fiber and lay mode: as shown in Figure 7, optical fiber is laid along each feed rod according to horizontal S shape.The advantage that this optical fiber is laid mode is to save optical fiber deployment cost.
The brillouin distributed optical fiber sensing device adopting in the present invention can be BOTDA(Brilouin Optical Time-Domain Analysis, Brillouin optical time domain analysis) sensor, BOTDR(Brillouin Optical Time-Domain Reflectometry, Brillouin light Time Domain Reflectometry) sensor, BOFDA(Brillouin Optical Frequency Domain Analysis, Brillouin light frequency-domain analysis) one in sensor, when concrete enforcement, need select according to different performance feature and the applicable situation of above various sensors.
In a kind of preferred embodiment, the present invention selects BOTDA sensor, and this sensor is based on stimulated Brillouin scattering effect design, and it has that detection signal is strong, resolution is high and the advantage such as the response time is short.
Common BOTDA sensor has two kinds of laser generation schemes at present, is respectively twin-laser scheme and single laser instrument scheme, and wherein, twin-laser scheme need to be with frequency locking circuit by the Frequency Locking of two laser instruments, and cost is higher; And it is not single laser instrument scheme cost is lower, high to the stability requirement of laser frequency.
In a kind of preferred embodiment, the present invention adopts the BOTDA sensor of single laser instrument scheme.As shown in Figure 8, the BOTDA working sensor principle of single laser instrument scheme is as follows: proportion is f
0wavelength is the single laser instrument of λ, and the two-way laser after optical branching device shunt enters acousto-optic modulator respectively and electrooptic modulator is modulated, and forms pumping laser f
1with continuous probe light f
2, then pumping laser f
1with continuous probe light f
2in optical fiber, interact and stimulated Brillouin scattering occurs and produce Brillouin scattering light signal, detect this class Brillouin scattering light signal and it is analyzed, to pumping laser f
1with continuous probe light f
2difference on the frequency carry out continuous sweep, can determine the Brillouin shift of optical fiber diverse location, thereby obtain the temperature distribution information of whole optical fiber.
Because earthing pole is located in outer suburbs open field, in order to get easily the distributed intelligence of earthing pole temperature field, the present invention can be arranged at the place that maintains easily personnel's supervision away from earthing pole by brillouin distributed optical fiber sensing device and earthing pole temperature field monitoring main frame, preferably, can select brillouin distributed optical fiber sensing device and earthing pole temperature field monitoring main frame to be arranged in current conversion station.
In the present invention, the connection of brillouin distributed optical fiber sensing device and optical fiber can have following two kinds: a kind of is to make brillouin distributed optical fiber sensing device and the optical fiber direct of laying along earthing pole connect in succession, need between brillouin distributed optical fiber sensing device and earthing pole, lay in this case the optical fiber that service is provided for temperature monitoring separately, cost is higher; Another kind is to utilize existing OPGW(Optical Fiber Composite Overhead Ground Wire, Optical Fiber composite overhead Ground Wire) brillouin distributed optical fiber sensing device and the optical fiber of laying along earthing pole are coupled together, be that brillouin distributed optical fiber sensing device is connected with one end of OPGW, the other end of OPGW and the optical fiber phase welding of laying along earthing pole, OPGW has ground wire and communications optical cable dual-use function concurrently, this situation has been utilized existing OPGW, and required optical fiber is shorter, and cost is lower.
In a kind of preferred embodiment, the present invention also utilizes the fiber optic temperature distributed data that many wavelet transformation techniques obtain brillouin distributed optical fiber sensing device to carry out denoising, and then restores more real earthing pole temperature profile data.
Concrete, as shown in Figure 9, earthing pole temperature field monitoring main frame carries out many wavelet transform process to the temperature profile data of optical fiber, comprises the steps: to obtain earthing pole temperature field distribution situation
Step S91, utilizes prefilter to carry out pre-service to the temperature profile data of described optical fiber, obtains the required vector signal of many wavelet decomposition.
Concrete, before many wavelet transformations, the fiber optic temperature distributed data gathering need to be converted to vector signal, it is pre-filtering, because Hardin-Roach pre-filtering can keep orthogonality and degree of approximation simultaneously, preferably, the present invention adopts Hardin-Roach prefilter to carry out pre-filtering to fiber optic temperature distributed data x (t), obtains the expansion coefficient of x (t).
Step S92, utilizes two scaling Equations to carry out many wavelet decomposition to described vector signal, obtains low frequency coefficient and high frequency coefficient after decomposing.
Concrete, utilize two scaling Equations that the expansion coefficient of x (t) is carried out to many wavelet decomposition, obtain low frequency outline portion and high frequency detail section after decomposing; Repeat many wavelet decomposition, until by the signal decomposition of required frequency range out.
Step S93, adopts related function wave filter to carry out correlation filtering to described low frequency coefficient, removes the white noise signal in described low frequency coefficient, obtains the low frequency coefficient after denoising.
Concrete, low frequency coefficient after decomposing is done to correlation filtering processing: the ultralow frequency component of this coefficient representation signal, it is representation temperature field information, because noise is generally the broadband signal of linear independence, and temperature field information is the signal of ultralow frequency linear dependence, therefore, utilize the correlativity of signal can be by the noise signal filtering being blended in temperature field information frequency range.
Step S94, according to the high frequency noise-removed threshold value of setting, described high frequency coefficient is carried out to denoising, the high frequency coefficient that is less than described high frequency noise-removed threshold value is set to zero, and the high frequency coefficient that is greater than described high frequency noise-removed threshold value remains unchanged, and obtains the high frequency coefficient after denoising.
Concrete, the high frequency coefficient after decomposing is done to threshold values processing: the high fdrequency component of this coefficient representation signal, i.e. noise component, can do denoising to high frequency coefficient according to predefined threshold values (being high frequency noise-removed threshold value).
Step S95, utilizes vector signal described in low frequency coefficient after described denoising and high frequency coefficient reconstruct.
Concrete, by above-mentioned many wavelet transformations and correlation filtering, just the noise signal in high frequency coefficient and low frequency coefficient can be filtered out, and by the high frequency coefficient after denoising and low frequency coefficient reconstructed vector signal.
Step S96, carries out described pretreated inverse operation processing to the vector signal of described reconstruct, obtains the temperature profile data of described earthing pole.
Prior art adopts wavelet transformation to carry out denoising to signal more, but because the time-frequency domain of wavelet transformation own cannot meet the feature of tight supportive simultaneously, in the time of signal decomposition, have spectral leakage problem, this will cause signal denoising hydraulic performance decline, even cannot extract real signal.And many wavelet transformations are propositions of on the basis of the wavelet transformation spectral leakage problem when solving wavelet decomposition, can carry out time and frequency domain analysis to signal simultaneously, there is the dual tight supportive of time-frequency domain, ensure the multiresolution analysis of signal decomposition, effectively the noise in filtered signal.
This scheme has been utilized many wavelet transformations to carry out time and frequency domain analysis to signal simultaneously, has been had the features such as time frequency compactly supported support characteristic that multiresolution and wavelet analysis cannot have, can from mixed noisy fiber optic temperature distributed data, restore real earthing pole temperature profile data preferably.
The present invention, with very example of ± 500kV Zhaotong current conversion station DC earthing, has designed a kind of earthing pole temperature field on-Line Monitor Device based on Brillouin scattering principle and many Wavelet Denoising Methods.
(1) ± 500kV Zhaotong current conversion station earthing pole overview
± 500kV Zhaotong current conversion station ground connection is two annulars very with one heart, interior ring radius 175m(girth 1099m), outer shroud radius is 250m(girth 1570m), electrode buried depth is 3.5m, adopts the shallow buried type land earthing pole of direct-buried cable drainage way.The electrode material of feed rod is high-silicon chromium iron rod.
Drainage and distribution cable all adopt copper core cable to be drawn and be connected to distribution cable electric current introducing point by bus rod, the total radical of leading cable to outer shroud and interior ring is 8, on each ring, have respectively 4 electric currents to introduce point, the cable radical of introducing point by bus rod to each electric current is 2.Leading cable is welded at polar ring place and distribution cable, and use epoxy sealing.
(2) optical fiber layout scheme
Adopt the single-mode fiber based on Brillouin scattering principle to lay along earthing pole location, single-mode fiber 40km comes and goes (one way 20km), and spatial resolution is 1 meter, and continuous measuring hours is less than 10 minutes, and temperature measurement accuracy is ± 0.5 DEG C, 0.5 meter of sampling interval.
As shown in Figure 5, in the horizontal direction, optical fiber is accessed by terminal tower, then be divided into two parts, Part I is linked into a certain monitor well of interior ring by terminal tower, then lay along interior ring coke track counterclockwise, and length is 1/8 of inner circumference length, then along the directions of rays being formed by the center of circle and the current loca outer shroud of layouting, layout along outer shroud feed rod, length is 1/8 of outer shroud girth again, is turning back to interior ring, by that analogy, until intersect 1/2 of the complete interior ring of cloth and outer shroud; Part II is the monitor well that is linked into outer shroud by terminal tower, then similar with Part I, intersect the complete interior ring of cloth and outer shroud other 1/2.This wire laying mode has been taken into account along the Temperature Distribution of annular direction with along the radial temperature profile of radial direction simultaneously.
As shown in figure 10, in depth direction, to be defined as sample plane A, sample plane B apart from the plane of earthing pole place plane 0.75m, 1.65m and 3.5m and sample plane C(is ground surface successively), in these sample plane according to horizontal direction layout scheme laying optical fiber as shown in Figure 5.This wire laying mode has been considered the factor of temperature conduction, has taken into account depth direction layout cost and Monitoring Data integrality, and the temperature field that can more completely monitor whole earthing pole distributes.
Because the spatial resolution of optical fiber is 1 meter, and the depth spacing of earthing pole place plane and sample plane A is 0.75m, sample plane A, the depth spacing of B is 0.9m, sample plane B, the depth spacing of C is 1.85m, in order to obtain the Temperature Distribution situation on this segment distance between neighbouring sample plane, optical fiber along depth direction need adopt redundancy processing mode, example as shown in figure 10, optical fiber length between earthing pole place plane and sample plane A is 1m, sample plane A, optical fiber length between B is 1m, sample plane B, optical fiber length between C is 2m, carrying out curve by the optical fiber of depth direction layouts, ensure that the projected length of this optical fiber in depth direction is respectively 0.75m, 0.9m and 1.85m, taking can meeting spatial resolution as the condition of 1m.
In terminal tower splice tray position, two single-mode fibers in DC line OPGW are carried out respectively to welding with the optical fiber head and the tail of laying along earthing pole, and form a loop by the BOTDA sensor host machine that is positioned at current conversion station, realize the connection of communication port (OPGW) and sensing passage (optical fiber of laying along earthing pole).
(3) BOTDA sensor setting
In ± 500kV Zhaotong current conversion station, dispose BOTDA sensor host machine, distance sensing is single-mode fiber 50km, and grating wavelength scope is 1510-1590nm, and temperature measurement accuracy is ± 0.5 DEG C, and temperature-measuring range is-40 DEG C-220 DEG C.
(4) earthing pole temperature field monitoring main frame setting
On the earthing pole temperature field of ± current conversion station inside, 500kV Zhaotong monitoring main frame, load the embedded data process software based on many Wavelet Denoising Methods, first this embedded data process software gathers by data collecting card the fiber optic temperature distributed data that BOTDA sensor obtains, then utilize Hardin-Roach prefilter to carry out pre-service to fiber optic temperature distributed data, be converted to the vector signal that many wavelet transformations need; By the many small echos of DHGM, data are carried out to Multiresolution Decomposition again, obtain low frequency signal and each layer of high-frequency signal after decomposing; Adopt again related function wave filter to carry out correlation filtering to the low frequency signal after decomposing, remove the white noise signal in low frequency signal; According to the Wavelet Denoising Method threshold value coefficient of setting, high-frequency signal is carried out to threshold process again, be less than the high frequency coefficient zero setting of setting threshold, the high frequency coefficient that is greater than setting threshold remains unchanged; Recycle low frequency signal after treatment and high-frequency signal reconstruct temperature field vector signal; Finally utilize aftertreatment that vector signal is reduced into earthing pole temperature field data.
Accordingly, the present invention also provides a kind of System for HVDC System Earth Pole temperature field monitoring method, and as shown in figure 11, the method comprises:
Step S111, along earthing pole laying optical fiber;
Step S112, sends laser to described optical fiber, detects the Brillouin scattering producing in described optical fiber, and based on Brillouin scattering principle, described Brillouin scattering is carried out to analyzing and processing, obtains the temperature profile data of described optical fiber;
Step S113, determines the temperature field distribution situation of described earthing pole according to the temperature profile data of described optical fiber.
In a kind of preferred embodiment, step S113 is specially: the temperature profile data of described optical fiber is carried out to many wavelet transform process, obtain the temperature profile data of described earthing pole.
Preferably, step S113 can comprise the steps: to utilize prefilter to carry out pre-service to the temperature profile data of described optical fiber, obtains the required vector signal of many wavelet decomposition; Utilize two scaling Equations to carry out many wavelet decomposition to described vector signal, obtain low frequency coefficient and high frequency coefficient after decomposing; Adopt related function wave filter to carry out correlation filtering to described low frequency coefficient, remove the white noise signal in described low frequency coefficient, obtain the low frequency coefficient after denoising; According to the high frequency noise-removed threshold value of setting, described high frequency coefficient is carried out to denoising, the high frequency coefficient that is less than described high frequency noise-removed threshold value is set to zero, the high frequency coefficient that is greater than described high frequency noise-removed threshold value remains unchanged, and obtains the high frequency coefficient after denoising; Utilize vector signal described in low frequency coefficient after described denoising and high frequency coefficient reconstruct; The vector signal of described reconstruct is carried out to described pretreated inverse operation processing, obtain the temperature profile data of described earthing pole.
Preferably, prefilter is Hardin-Roach prefilter.
In the time of the very two annular of ground connection, in a kind of preferred embodiment, step S111 specifically comprises along earthing pole laying optical fiber: along interior ring coke track, the outer shroud coke track laying optical fiber of described earthing pole.
Preferably, when the very two annular of ground connection, step S111 also comprises along earthing pole laying optical fiber: along the radial direction laying optical fiber of described interior ring coke track, outer shroud coke track.
Preferably, when the very two annular of ground connection, step S111 also comprises along earthing pole laying optical fiber: at the depth direction laying optical fiber perpendicular to described earthing pole place plane, and with described earthing pole place plane laying optical fiber in the plane of setpoint distance.
In the time of the very vertical shape of ground connection, in a kind of preferred embodiment, step S111 specifically comprises along earthing pole laying optical fiber: along each feed rod laying optical fiber of described earthing pole.Preferably, when the very vertical shape of ground connection, step S111 according to horizontal S shape along described each feed rod laying optical fiber.
In a kind of preferred embodiment, step S112 specifically comprises: send respectively pumping laser and continuous probe laser to described optical fiber, and the difference on the frequency of described pumping laser and continuous probe laser is carried out to continuous sweep; Detect the Brillouin scattering producing in described optical fiber; Based on stimulated Brillouin scattering effect, described Brillouin scattering is carried out to analyzing and processing, obtain the temperature profile data of described optical fiber.Preferably, described pumping laser and continuous probe laser are produced by single laser instrument.
Invention thought based on identical realizes System for HVDC System Earth Pole temperature field monitoring method shown in Figure 11 with the System for HVDC System Earth Pole temperature field monitoring device shown in Fig. 4, its embodiment can, with reference to the aforementioned introduction to Fig. 4 shown device, repeat no more herein.
In sum, the embodiment of the present invention provides System for HVDC System Earth Pole temperature field monitoring system and method have following beneficial effect:
(1) utilize the optical communication technique of Brillouin scattering principle to solve prior art the problem of power-supply device need to be provided near earthing pole location, and avoided losing the generation of problem because power supply deficiency causes image data;
(2) utilize optical communication and optical sensing, improved ability and the signal antijamming capability of Long-range Data Transmission;
(3) temperature acquisition is put crypto set more and can be covered the bulk temperature field of earthing pole, can effectively restore real earthing pole temperature field situation;
(4) from time domain and frequency domain two aspects, signal is analyzed, by many Wavelet Denoising Methods, can effectively be removed noise, effectively restore real temperature field signal, improved the confidence level of temperature field data.
Above-described specific embodiment; object of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the foregoing is only specific embodiments of the invention; the protection domain being not intended to limit the present invention; within the spirit and principles in the present invention all, any amendment of making, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.
Claims (10)
1. a System for HVDC System Earth Pole temperature field monitoring system, is characterized in that, comprising: optical fiber, brillouin distributed optical fiber sensing device and earthing pole temperature field monitoring main frame, wherein,
Described optical fiber is laid along earthing pole;
Described brillouin distributed optical fiber sensing device connects described optical fiber, for sending laser to described optical fiber, detect the Brillouin scattering producing in described optical fiber, and based on Brillouin scattering principle, described Brillouin scattering is carried out to analyzing and processing, obtain the temperature profile data of described optical fiber;
Monitoring main frame in described earthing pole temperature field is for determining the temperature field distribution situation of described earthing pole according to the temperature profile data of described optical fiber.
2. system according to claim 1, is characterized in that, described earthing pole temperature field monitoring main frame, specifically for the temperature profile data of described optical fiber is carried out to many wavelet transform process, obtains the temperature profile data of described earthing pole.
3. system according to claim 2, is characterized in that, described earthing pole temperature field monitoring main frame further specifically for:
Utilize prefilter to carry out pre-service to the temperature profile data of described optical fiber, obtain the required vector signal of many wavelet decomposition;
Utilize two scaling Equations to carry out many wavelet decomposition to described vector signal, obtain low frequency coefficient and high frequency coefficient after decomposing;
Adopt related function wave filter to carry out correlation filtering to described low frequency coefficient, remove the white noise signal in described low frequency coefficient, obtain the low frequency coefficient after denoising;
According to the high frequency noise-removed threshold value of setting, described high frequency coefficient is carried out to denoising, the high frequency coefficient that is less than described high frequency noise-removed threshold value is set to zero, the high frequency coefficient that is greater than described high frequency noise-removed threshold value remains unchanged, and obtains the high frequency coefficient after denoising;
Utilize vector signal described in low frequency coefficient after described denoising and high frequency coefficient reconstruct;
The vector signal of described reconstruct is carried out to described pretreated inverse operation processing, obtain the temperature profile data of described earthing pole.
4. a System for HVDC System Earth Pole temperature field monitoring method, is characterized in that, comprising:
Along earthing pole laying optical fiber;
Send laser to described optical fiber, detect the Brillouin scattering producing in described optical fiber, and based on Brillouin scattering principle, described Brillouin scattering is carried out to analyzing and processing, obtain the temperature profile data of described optical fiber;
Determine the temperature field distribution situation of described earthing pole according to the temperature profile data of described optical fiber.
5. method according to claim 4, it is characterized in that, the described temperature profile data according to described optical fiber is determined the temperature field distribution situation of described earthing pole, specifically comprise: the temperature profile data of described optical fiber is carried out to many wavelet transform process, obtain the temperature profile data of described earthing pole.
6. method according to claim 5, is characterized in that, described carries out many wavelet transform process to the temperature profile data of described optical fiber, obtains the temperature profile data of described earthing pole, specifically comprises:
Utilize prefilter to carry out pre-service to the temperature profile data of described optical fiber, obtain the required vector signal of many wavelet decomposition;
Utilize two scaling Equations to carry out many wavelet decomposition to described vector signal, obtain low frequency coefficient and high frequency coefficient after decomposing;
Adopt related function wave filter to carry out correlation filtering to described low frequency coefficient, remove the white noise signal in described low frequency coefficient, obtain the low frequency coefficient after denoising;
According to the high frequency noise-removed threshold value of setting, described high frequency coefficient is carried out to denoising, the high frequency coefficient that is less than described high frequency noise-removed threshold value is set to zero, the high frequency coefficient that is greater than described high frequency noise-removed threshold value remains unchanged, and obtains the high frequency coefficient after denoising;
Utilize vector signal described in low frequency coefficient after described denoising and high frequency coefficient reconstruct;
The vector signal of described reconstruct is carried out to described pretreated inverse operation processing, obtain the temperature profile data of described earthing pole.
7. method according to claim 4, is characterized in that, when the very two annular of described ground connection, described specifically comprises along earthing pole laying optical fiber: along interior ring coke track, the outer shroud coke track laying optical fiber of described earthing pole.
8. method according to claim 7, is characterized in that, described also comprises along earthing pole laying optical fiber: along the radial direction laying optical fiber of described interior ring coke track, outer shroud coke track.
9. method according to claim 7, it is characterized in that, described also comprises along earthing pole laying optical fiber: at the depth direction laying optical fiber perpendicular to described earthing pole place plane, and with described earthing pole place plane laying optical fiber in the plane of setpoint distance.
10. method according to claim 4, it is characterized in that, described sends laser to described optical fiber, detect the Brillouin scattering producing in described optical fiber, and based on Brillouin scattering principle, described Brillouin scattering is carried out to analyzing and processing, the temperature profile data that obtains described optical fiber, specifically comprises:
Send respectively pumping laser and continuous probe laser to described optical fiber, and the difference on the frequency of described pumping laser and continuous probe laser is carried out to continuous sweep;
Detect the Brillouin scattering producing in described optical fiber;
Based on stimulated Brillouin scattering effect, described Brillouin scattering is carried out to analyzing and processing, obtain the temperature profile data of described optical fiber.
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