CN103913252B - 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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- CN103913252B CN103913252B CN201410098760.0A CN201410098760A CN103913252B CN 103913252 B CN103913252 B CN 103913252B CN 201410098760 A CN201410098760 A CN 201410098760A CN 103913252 B CN103913252 B CN 103913252B
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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 technical field of HVDC transmission, 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 geographically distributed pole are unbalanced, and determining China can source remote distance, the extensive inexorable trend flowed.HVDC(High-Voltage Direct Current, D.C. high voltage transmission), advantage that fed distance far away large with its power transmission capacity, in energy flowing, there is irreplaceable status.
High voltage dc transmission technology is different from ac transmission in a lot, has its self intrinsic feature and technical requirement, and earthing pole designing technique is exactly an example wherein.HVDC (High Voltage Direct Current) transmission system is separated working earthing and safeguard protection ground connection, 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 in DC transmission system is run: one is directly for a long time for system transmits electric power, and improves the reliability of system cloud gray model; Two is clamp down on current conversion station neutral point potential, avoids the two poles of the earth voltage-to-ground uneven and damages equipment.
The HVDC (High Voltage Direct Current) transmission system 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 constantly for straight-flow system transmits DC current, thus can form the cocurrent flow loop of sending end current conversion station, aerial condutor, receiving end current conversion station and the earth composition, ensures to carry DC power constantly.The DC current of sending end current conversion station is caused by aerial condutor on the equipment of earth electrode field center, by flow guide system feed-in the earth, then by greatly flowing to receiving end current conversion station earthing pole, thus completes ground return circuit.
Figure 1 shows that earth electrode diversion system forms schematic diagram, DC current to be drawn by aerial condutor and is connected to terminal tower by current conversion station, at terminal tower hollow wire DC current drawn and be connected to water conservancy diversion lead-in wire, gone between DC current to be drawn be connected to by water conservancy diversion again and be embedded in terminal tower feed cable lower peripherally, finally DC current to be caused on earthing pole by feed cable and be transferred to greatly.
Earthing pole common at present can be divided into the type such as many annulars, vertical shape, ellipse, star according to the difference of shape.As shown in Figure 2, the feed rod that vertical shape earthing pole is generally vertically embedded in underground by some forms, and each root feed rod is all connected with feed cable, introduces the earth for the DC current transmitted by feed cable; As shown in Figure 3, many annulars earthing pole generally by shallow embedding in underground and two annular coke tracks with one heart parallel to the ground form, coke track is connected with feed cable, for the DC current introducing transmit by feed cable greatly.
Flowed into the earth current of the earth by earthing pole, the distribution on earthing pole is uneven.Generally speaking, the end overflow of earthing pole is maximum, and middle part is minimum, and its difference can reach several times.It is low that this distribution result in earthing pole utilization factor, the overheated and premature corrosion of partial portion, the problems such as surface potential skewness.Now, in order to save land used and reduce construction costs, multiple DC transmission system is generally adopted to share the mode of an earthing pole.But for the mode of One Common Earthing Electrode, when adopting one pole the earth or bipolar off-center operation mode in the straight-flow system of One Common Earthing Electrode, big current flows through earthing pole and the soil around earthing pole can be caused to generate heat, the soil moisture is raised, time serious, the normal work of earthed system may be affected, if earthing pole works in the too high environment of temperature, occur that the probability burnt will increase greatly, and will more serious consequence be produced.As the south bridge direct current grounding pole of the Shanghai end that 500kV DC transmission system Pueraria lobota is reached the standard grade, Zeng Yinwei distribution of current is uneven 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 the temperature conditions grasping earth electrode field region at any time.
Because earthing pole is in underground, prior art general is arranged at the monitor well in earth electrode field region to obtain the temperature information at earthing pole scene, its concrete scheme is: arrange monitor well in the place of feed cable access point, monitor well adopts pvc pipe, monitor well is vertically installed in above earthing pole or near earthing pole both sides, dew is opened in bottom, upper end flushes with ground, detect the temperature near relevant position at the diverse location place mounting temperature sensor of monitor well, and by temperature sensor, the temperature data of collection is radioed to distance host.But this scheme has following shortcoming:
1, by the restriction of the chosen position, temperature sensor quantity etc. of monitor well, the temperature information collected can not cover the bulk temperature field of earthing pole, effectively can not restore real earthing pole temperature field situation;
2, Real-time Collection temperature information is wanted, 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 have employed wind light mutual complementing mode and powers, also the electricity shortage situation existed to a certain degree occurs, and causes the temperature information detected to be lost;
3, the performance requirement of wireless transmission temperature acquisition data to equipment is higher, and transmission range is shorter, poor anti jamming capability.
The present invention is under National 863 planning item fund (2012AA050209) is subsidized, and proposes 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 power supply and the easy problem such as 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 produced in described optical fiber, and based on Brillouin scattering principle, analyzing and processing is carried out to described Brillouin scattering, obtain the temperature profile data of described optical fiber;
Described earthing pole temperature field monitoring main frame is used for the thermo parameters method situation determining 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 produced in described optical fiber, and based on Brillouin scattering principle, analyzing and processing is carried out to described Brillouin scattering, obtain the temperature profile data of described optical fiber;
The thermo parameters method situation of described earthing pole is determined according to the temperature profile data of described optical fiber.
By means of technique scheme, the present invention utilizes the Fibre Optical Communication Technology of Brillouin scattering principle to obtain the temperature of the optical fiber each position laid along earthing pole, and then determine the thermo parameters method situation of earthing pole, compared to prior art, present invention, avoiding and need to provide power-supply device at earth electrode field, avoid because power supply deficiency causes image data to lose the generation of problem, because optical fiber lays along earthing pole, its temperature acquisition point more crypto set and can cover the bulk temperature field of earthing pole, can restore real earthing pole temperature field situation effectively.
Accompanying drawing explanation
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 used required in describing embodiment 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, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
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 temperature field provided by the invention monitoring system structural representation;
Fig. 5 is a kind of fiber deployment mode schematic diagram for two annular earthing pole provided by the invention;
Fig. 6 is the another kind of fiber deployment mode schematic diagram for two annular earthing pole provided by the invention;
Fig. 7 is a kind of fiber deployment mode schematic diagram for vertical shape earthing pole provided by the invention;
Fig. 8 is the principle of work schematic diagram of the BOTDA sensor of the single laser scheme of employing provided by the invention;
Fig. 9 is that earthing pole temperature field provided by the invention monitoring main frame adopts multi-wavelet transformation to obtain the schematic flow sheet of earthing pole thermo parameters method situation;
Figure 10 is the fiber deployment mode schematic diagram that the specific embodiment of the invention provides;
Figure 11 is the particular flow sheet of System for HVDC System Earth Pole temperature field provided by the invention monitoring method.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained 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 connecting fiber 41, for sending laser to optical fiber 41, the Brillouin scattering produced in detection fiber 41, and based on Brillouin scattering principle, analyzing and processing is carried out to Brillouin scattering, obtain the temperature profile data of optical fiber 41; Monitoring main frame 43 in earthing pole temperature field is for the thermo parameters method situation of the temperature profile data determination earthing pole 40 according to optical fiber 41.
The present invention adopts along earthing pole laying optical fiber, and utilizes the Distributed Optical Fiber Sensing Techniques based on Brillouin scattering principle to obtain on optical fiber temperature everywhere, and then obtains the thermo parameters method situation of earthing pole.Because optical fiber itself does not need power supply, therefore present invention eliminates the trouble of installing power-supply device at earth electrode field, the problem causing image data to be lost because power supply is not enough can be avoided simultaneously; Further, because optical fiber lays along earthing pole, therefore temperature acquisition point more crypto set and can cover the bulk temperature field of earthing pole, can restore real earthing pole temperature field situation effectively; In addition, utilize the advantages such as the long transmission distance of optical fiber sensing technology, antijamming capability are strong, invention increases the ability of earthing pole temperature data remote transmission, be 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 needs each position making optical fiber cloth and earthing pole, and the concrete laying mode of optical fiber needs along with the shape difference of earthing pole and changes.
In a kind of preferred embodiment, if the very two annular of ground connection, namely earthing pole is made up of the concentric inner ring coke track of shallow embedding in underground, outer shroud coke track, then optical fiber is laid along the inner ring coke track of earthing pole, outer shroud coke track.
Preferably the invention provides following a kind of fiber deployment 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, the a certain monitor well of inner ring coke track is linked into by terminal tower, then counterclockwise to lay along inner ring coke track, laying length is 1/8 of inner ring girth, then the directions of rays connected and composed along the center of circle and current point 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 the directions of rays to connect and compose along the center of circle and current point turns back to inner ring, the rest may be inferred, until intersect 1/2 of the complete inner ring of cloth and outer shroud; Similar, another part is as shown in the solid arrow in Fig. 5, the a certain monitor well of outer shroud coke track is linked into by terminal tower, then counterclockwise to lay along outer shroud coke track, laying length is 1/8 of outer shroud girth, then the directions of rays connected and composed along the center of circle and current point is deployed to inner ring coke track, lay along inner ring coke track again, laying length is 1/8 of inner ring girth, and then the directions of rays to connect and compose along the center of circle and current point turns back to outer shroud, the rest may be inferred, until intersect 1/2 of the complete inner ring of cloth and outer shroud.Simultaneously the advantage of this fiber deployment mode takes into account along the circumferential Temperature Distribution in inner and outer rings direction and the radial temperature profile along radial direction, and fiber deployment did not only repeat around inside and outside two loop orbits, saved fiber deployment cost.
Preferably, the present invention also provides following a kind of fiber deployment mode: as shown in Figure 6, laying on the basis of mode as shown in Figure 5, also at the depth direction laying optical fiber perpendicular to earthing pole place plane, and (this plane is at least one in the plane apart from earthing pole place plane being setpoint distance, below this plane is become sample plane) interior laying optical fiber, the fiber deployment mode wherein in each sample plane is all consistent with the laying mode shown in Fig. 5.The advantage of this fiber deployment mode considers the temperature conduction factor of earthing pole to soil, takes into account the thermo parameters method situation on depth direction.
In another kind of preferred embodiment, if the very vertical shape of ground connection, namely earthing pole is made up of the feed rod that some are vertically embedded in underground, then optical fiber is laid along each feed rod of earthing pole.
Preferably, the invention provides following a kind of fiber deployment mode: as shown in Figure 7, optical fiber is laid along each feed rod according to the S shape of transverse direction.The advantage of this fiber deployment mode saves fiber deployment cost.
The brillouin distributed optical fiber sensing device adopted in the present invention can be BOTDA(Brilouin OpticalTime-Domain Analysis, Brillouin optical time domain analysis) sensor, BOTDR(Brillouin OpticalTime-Domain Reflectometry, Brillouin light Time Domain Reflectometry) sensor, BOFDA(BrillouinOptical Frequency Domain Analysis, Brillouin light frequency-domain analysis) one in sensor, during concrete enforcement, need select according to the different performance feature of above various sensor and applicable situation.
In a kind of preferred embodiment, the present invention selects BOTDA sensor, and this sensor is based on the design of stimulated Brillouin scattering effect, and it has that detection signal is strong, resolution is high and the advantage such as the response time is short.
BOTDA sensor common at present has two kinds of laser and produces scheme, is respectively twin-laser scheme and single laser scheme, and wherein, twin-laser scheme needs with frequency locking circuit by the Frequency Locking of two laser instruments, and cost is higher; And it is not single laser 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 scheme.As shown in Figure 8, the BOTDA sensor operating principles of single laser scheme is as follows: employing frequency 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
2interact in a fiber and stimulated Brillouin scattering occurs and produces Brillouin scattering light signal, detect this kind of 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, the Brillouin shift of optical fiber diverse location can be determined, thus obtain the temperature distribution information of whole optical fiber.
Because earthing pole is located in outer suburbs open field, in order to earthing pole thermo parameters method information can be got easily, brillouin distributed optical fiber sensing device and earthing pole temperature field monitoring main frame can be arranged at the place maintaining easily personnel's supervision away from earthing pole by the present invention, preferably, brillouin distributed optical fiber sensing device and earthing pole temperature field monitoring main frame can be selected to be arranged in current conversion station.
In the present invention, brillouin distributed optical fiber sensing device can have the following two kinds with the connection of optical fiber: a kind of is make brillouin distributed optical fiber sensing device directly be connected with the optical fiber laid along earthing pole, in this case need to lay between brillouin distributed optical fiber sensing device and earthing pole separately for temperature monitoring provides the optical fiber of service, cost is higher; Another kind utilizes existing OPGW(Optical Fiber Composite OverheadGround Wire, Optical Fiber composite overhead Ground Wire) brillouin distributed optical fiber sensing device and the Fiber connection laid along earthing pole are got up, namely brillouin distributed optical fiber sensing device is connected with one end of OPGW, the other end and the optical fiber phase welding of laying along earthing pole of OPGW, OPGW has ground wire and communications optical cable dual-use function concurrently, this situation make use of existing OPGW, and required optical fiber is shorter, and cost is lower.
In a kind of preferred embodiment, the present invention also utilizes multi-wavelet transformation technology to carry out denoising to the fiber optic temperature distributed data that brillouin distributed optical fiber sensing device obtains, 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 multi-wavelet transformation process to the temperature profile data of optical fiber, comprises the steps: to obtain earthing pole thermo parameters method situation
Step S91, utilizes prefilter to carry out pre-service to the temperature profile data of described optical fiber, obtains the vector signal needed for m ultiwavelet decomposition.
Concrete, before multi-wavelet transformation, the fiber optic temperature distributed data gathering is needed to be converted to vector signal, i.e. 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 Double-scaling equation to carry out m ultiwavelet decomposition to described vector signal, obtains the low frequency coefficient after decomposing and high frequency coefficient.
Concrete, utilize Double-scaling equation that the expansion coefficient of x (t) is carried out m ultiwavelet decomposition, obtain the low frequency outline portion after decomposing and high frequency detail part; Repeat m ultiwavelet to decompose, 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, obtain the low frequency coefficient after denoising.
Concrete, correlation filtering process is done to the low frequency coefficient after decomposing: the ultralow frequency component of this coefficient representation signal, i.e. representation temperature field information, due to the broadband signal that noise is generally linear independence, and temperature field information is the signal of ultralow frequency linear correlation, therefore, the correlativity of signal is utilized to be mixed into the noise signal filtering in temperature field information frequency range.
Step S94, high frequency noise-removed threshold value according to setting carries out denoising to described high frequency coefficient, the high frequency coefficient being less than described high frequency noise-removed threshold value is set to zero, and the high frequency coefficient being greater than described high frequency noise-removed threshold value remains unchanged, and obtains the high frequency coefficient after denoising.
Concrete, threshold values process is done to the high frequency coefficient after decomposing: the high fdrequency component of this coefficient representation signal, i.e. noise component, denoising can be done according to the threshold values preset (i.e. high frequency noise-removed threshold value) to high frequency coefficient.
Step S95, utilizes the low frequency coefficient after described denoising and high frequency coefficient to reconstruct described vector signal.
Concrete, by above-mentioned multi-wavelet transformation 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 process to the vector signal of described reconstruct, obtains the temperature profile data of described earthing pole.
Prior art many employings wavelet transformation carries out denoising to signal, but because the time-frequency domain of wavelet transformation own cannot meet the feature of compactly supported simultaneously, there is spectral leakage problem when signal decomposition, this will cause signal denoising hydraulic performance decline, even cannot extract real signal.And multi-wavelet transformation be on the basis of wavelet transformation in order to solve wavelet decomposition time the proposition of spectral leakage problem, time and frequency domain analysis can be carried out to signal simultaneously, there is the dual compactly supported of time-frequency domain, ensure that the multiresolution analysis of signal decomposition, can noise effectively in filtered signal.
The program make use of multi-wavelet transformation and can carry out time and frequency domain analysis to signal simultaneously, have the features such as the time frequency compactly supported support characteristic that multiresolution and wavelet analysis cannot have, and can restore real earthing pole temperature profile data preferably from mixed noisy fiber optic temperature distributed data.
The present invention with ± 500kV Zhaotong current conversion station DC earthing is very routine, devises a kind of earthing pole temperature field on-Line Monitor Device based on Brillouin scattering principle and m ultiwavelet denoising.
(1) ± 500kV Zhaotong current conversion station earthing pole overview
± 500kV Zhaotong current conversion station ground connection is two annular very with one heart, inner 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 by bus rod and are connected to distribution cable electric current introducing point, the total radical of leading cable to outer shroud and inner ring is 8, each ring has respectively 4 electric currents introduce point, the cable radical namely introducing point by bus rod to each electric current is 2.Leading cable is welded with distribution cable at polar ring place, and uses epoxy sealing.
(2) fiber deployment scheme
Adopt and lay along earthing pole location based on the single-mode fiber of Brillouin scattering principle, 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, sampling interval 0.5 meter.
As shown in Figure 5, in the horizontal direction, optical fiber is accessed by terminal tower, then two parts are divided into, Part I is linked into a certain monitor well of inner ring by terminal tower, and then counterclockwise along the laying of inner ring coke track, length is 1/8 of inner ring girth, then to layout outer shroud along the directions of rays be made up of the center of circle and current point, layout along outer shroud feed rod, length is 1/8 of outer shroud girth, is turning back to inner ring again, by that analogy, until intersect 1/2 of the complete inner ring of cloth and outer shroud; Part II is the monitor well being linked into outer shroud by terminal tower, then similar with Part I, intersect the complete inner ring of cloth and outer shroud other 1/2.This wire laying mode has taken into account the Temperature Distribution along annular direction and the radial temperature profile along radial direction simultaneously.
As shown in Figure 10, in depth direction, successively the plane of distance earthing pole place plane 0.75m, 1.65m and 3.5m is defined as sample plane A, sample plane B and sample plane C(and ground surface), according to horizontal direction layout scheme laying optical fiber as shown in Figure 5 in these sample plane.This wire laying mode considers the factor of temperature conduction, has taken into account depth direction and to have layouted cost and Monitoring Data integrality, more completely can monitor the thermo parameters method of whole earthing pole.
Spatial resolution due to 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 the profiling temperatures between neighbouring sample plane on this segment distance can be obtained, optical fiber along depth direction need adopt redundancy processing mode, such as shown in Figure 10, optical fiber between earthing pole place plane and sample plane A is long is 1m, sample plane A, optical fiber between B is long is 1m, sample plane B, optical fiber between C is long is 2m, optical fiber by depth direction carries out curve and layouts, ensure that the projected length of this optical fiber on depth direction is respectively 0.75m, 0.9m and 1.85m, with can the meeting spatial resolution condition that is 1m.
In terminal tower splice tray position, the single-mode fiber of two in DC line OPGW and the optical fiber head and the tail laid along earthing pole are carried out welding respectively, and form a loop by the BOTDA sensor host machine being positioned at current conversion station, realize the connection of communication port (OPGW) and sensing passage (optical fiber along earthing pole is laid).
(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 range is 1510-1590nm, and temperature measurement accuracy is ± 0.5 DEG C, and temperature-measuring range is-40 DEG C-220 DEG C.
(4) monitoring main frame in earthing pole temperature field is arranged
The earthing pole temperature field monitoring main frame of ± current conversion station inside, 500kV Zhaotong loads the embedded data process software based on m ultiwavelet denoising, first this embedded data process software gathers the fiber optic temperature distributed data of BOTDA sensor acquisition by data collecting card, then utilize Hardin-Roach prefilter to carry out pre-service to fiber optic temperature distributed data, be converted to the vector signal that multi-wavelet transformation needs; By DHGM m ultiwavelet, Multiresolution Decomposition is carried out to data again, obtain the low frequency signal after decomposing and each layer high-frequency signal; Adopt related function wave filter to carry out correlation filtering to the low frequency signal after decomposition again, remove the white noise signal in low frequency signal; Again according to the wavelet de-noising threshold coefficient of setting, carry out threshold process to high-frequency signal, be less than the high frequency coefficient zero setting of setting threshold value, the high frequency coefficient being greater than setting threshold value remains unchanged; Low frequency signal after recycling process and high-frequency signal remodeling temperature field vector signal; Aftertreatment is finally utilized vector signal to be 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 produced in described optical fiber, and carry out analyzing and processing based on Brillouin scattering principle to described Brillouin scattering, obtain the temperature profile data of described optical fiber;
Step S113, determines the thermo parameters method 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: carry out multi-wavelet transformation process to the temperature profile data of described optical fiber, 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 vector signal needed for m ultiwavelet decomposition; Utilize Double-scaling equation to carry out m ultiwavelet decomposition to described vector signal, obtain the low frequency coefficient after decomposing and high frequency coefficient; 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; High frequency noise-removed threshold value according to setting carries out denoising to described high frequency coefficient, and the high frequency coefficient being less than described high frequency noise-removed threshold value is set to zero, and the high frequency coefficient being greater than described high frequency noise-removed threshold value remains unchanged, and obtains the high frequency coefficient after denoising; The low frequency coefficient after described denoising and high frequency coefficient is utilized to reconstruct described vector signal; Described pretreated inverse operation process is carried out to the vector signal of described reconstruct, obtains the temperature profile data of described earthing pole.
Preferably, prefilter is Hardin-Roach prefilter.
When ground connection very two annular time, in a kind of preferred embodiment, step S111 specifically comprises along earthing pole laying optical fiber: along inner ring coke track, the outer shroud coke track laying optical fiber of described earthing pole.
Preferably, ground connection very two annular time, step S111 also comprises along earthing pole laying optical fiber: along the radial direction laying optical fiber of described inner ring coke track, outer shroud coke track.
Preferably, ground connection very two annular time, 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 at a distance of setpoint distance plane in laying optical fiber.
When 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, during the very vertical shape of ground connection, step S111 according to the S shape of transverse direction along each feed rod laying optical fiber described.
In a kind of preferred embodiment, step S112 specifically comprises: send pumping laser and continuous probe laser respectively to described optical fiber, and carries out continuous sweep to the difference on the frequency of described pumping laser and continuous probe laser; Detect the Brillouin scattering produced in described optical fiber; Based on stimulated Brillouin scattering effect, analyzing and processing is carried out to described Brillouin scattering, obtain the temperature profile data of described optical fiber.Preferably, described pumping laser and continuous probe laser are produced by single laser instrument.
System for HVDC System Earth Pole temperature field monitoring method shown in Figure 11 realizes based on identical invention thought with the System for HVDC System Earth Pole temperature field monitoring device shown in Fig. 4, its embodiment can refer to the aforementioned introduction to Fig. 4 shown device, repeats no more herein.
In sum, the System for HVDC System Earth Pole temperature field monitoring system that provides of the embodiment of the present invention and method have following beneficial effect:
(1) utilize the optical communication technique of Brillouin scattering principle to solve prior art and need to provide the problem of power-supply device near earthing pole location, and avoid because power supply deficiency causes image data to lose the generation of problem;
(2) utilize optical communication and optical sensing, improve ability and the signal antijamming capability of Long-range Data Transmission;
(3) temperature acquisition point more crypto set and can cover the bulk temperature field of earthing pole, can restore real earthing pole temperature field situation effectively;
(4) from time domain and frequency domain two aspect, signal is analyzed, by m ultiwavelet denoising, effectively can remove noise, effectively restore real temperature field signal, improve the confidence level of temperature field data.
Above-described specific embodiment; object of the present invention, technical scheme and beneficial effect are further described; be understood that; the foregoing is only specific embodiments of the invention; the protection domain be not intended to limit the present invention; within the spirit and principles in the present invention all, any amendment made, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (9)
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 produced in described optical fiber, and based on Brillouin scattering principle, analyzing and processing is carried out to described Brillouin scattering, obtain the temperature profile data of described optical fiber;
Described earthing pole temperature field monitoring main frame is used for the thermo parameters method situation determining 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 carrying out multi-wavelet transformation process to the temperature profile data of described optical fiber, 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 vector signal needed for m ultiwavelet decomposition;
Utilize Double-scaling equation to carry out m ultiwavelet decomposition to described vector signal, obtain the low frequency coefficient after decomposing and high frequency coefficient;
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;
High frequency noise-removed threshold value according to setting carries out denoising to described high frequency coefficient, and the high frequency coefficient being less than described high frequency noise-removed threshold value is set to zero, and the high frequency coefficient being greater than described high frequency noise-removed threshold value remains unchanged, and obtains the high frequency coefficient after denoising;
The low frequency coefficient after described denoising and high frequency coefficient is utilized to reconstruct described vector signal;
Described pretreated inverse operation process is carried out to the vector signal of described reconstruct, obtains 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 produced in described optical fiber, and based on Brillouin scattering principle, analyzing and processing is carried out to described Brillouin scattering, obtain the temperature profile data of described optical fiber;
The thermo parameters method situation of described earthing pole is determined according to the temperature profile data of described optical fiber.
5. method according to claim 4, it is characterized in that, the described thermo parameters method situation determining described earthing pole according to the temperature profile data of described optical fiber, specifically comprise: multi-wavelet transformation process is carried out to the temperature profile data of described optical fiber, obtains the temperature profile data of described earthing pole.
6. method according to claim 5, is characterized in that, the described temperature profile data to described optical fiber carries out multi-wavelet transformation process, 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 vector signal needed for m ultiwavelet decomposition;
Utilize Double-scaling equation to carry out m ultiwavelet decomposition to described vector signal, obtain the low frequency coefficient after decomposing and high frequency coefficient;
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;
High frequency noise-removed threshold value according to setting carries out denoising to described high frequency coefficient, and the high frequency coefficient being less than described high frequency noise-removed threshold value is set to zero, and the high frequency coefficient being greater than described high frequency noise-removed threshold value remains unchanged, and obtains the high frequency coefficient after denoising;
The low frequency coefficient after described denoising and high frequency coefficient is utilized to reconstruct described vector signal;
Described pretreated inverse operation process is carried out to the vector signal of described reconstruct, obtains the temperature profile data of described earthing pole.
7. method according to claim 4, it is characterized in that, described ground connection very two annular time, described specifically comprises along earthing pole laying optical fiber: along the inner ring coke track of described earthing pole, outer shroud coke track laying optical fiber and along the radial direction laying optical fiber between described inner ring coke track, outer shroud coke track.
8. 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 at a distance of setpoint distance plane in laying optical fiber.
9. method according to claim 4, it is characterized in that, described sends laser to described optical fiber, detect the Brillouin scattering produced in described optical fiber, and based on Brillouin scattering principle, analyzing and processing is carried out to described Brillouin scattering, obtain the temperature profile data of described optical fiber, specifically comprise:
Send pumping laser and continuous probe laser respectively to described optical fiber, and continuous sweep is carried out to the difference on the frequency of described pumping laser and continuous probe laser;
Detect the Brillouin scattering produced in described optical fiber;
Based on stimulated Brillouin scattering effect, analyzing and processing is carried out to described Brillouin scattering, obtain the temperature profile data of described optical fiber.
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| CN104201664B (en) * | 2014-09-17 | 2016-04-06 | 国家电网公司 | A kind of method for designing of the distributed earth electrode for HVDC (High Voltage Direct Current) transmission system |
| CN106813803A (en) * | 2017-01-22 | 2017-06-09 | 中国能源建设集团广东省电力设计研究院有限公司 | DC transmission deep well type earthing pole temperature measuring equipment, temperature online monitoring system and its monitoring method |
| CN107328490A (en) * | 2017-07-12 | 2017-11-07 | 北京优利康达科技股份有限公司 | A kind of wind generating set engine room temperature flow field test equipment and method of testing |
| CN111864688B (en) * | 2020-07-07 | 2022-08-23 | 中国南方电网有限责任公司超高压输电公司昆明局 | Ultra-high voltage direct current control protection system OTDR (optical time Domain reflectometer) layered multi-stage event accurate extraction and positioning method |
| CN112577997A (en) * | 2020-11-24 | 2021-03-30 | 国网陕西省电力公司电力科学研究院 | Ultrahigh-voltage direct-current grounding electrode soil corrosion monitoring device and method |
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| CN102074091B (en) * | 2011-01-26 | 2012-04-25 | 南京大学 | Distributed optical fiber temperature sensing wavelet analysis alarm method and system for tunnel fire |
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