CN101315403A - Ground net corrosion detection method and system - Google Patents

Ground net corrosion detection method and system Download PDF

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Publication number
CN101315403A
CN101315403A CNA200710099692XA CN200710099692A CN101315403A CN 101315403 A CN101315403 A CN 101315403A CN A200710099692X A CNA200710099692X A CN A200710099692XA CN 200710099692 A CN200710099692 A CN 200710099692A CN 101315403 A CN101315403 A CN 101315403A
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China
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corrosion
grounded screen
wavelet
electrochemical detection
metal
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CNA200710099692XA
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CN101315403B (en
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张秀丽
巩学海
宋诗哲
王天君
李永立
王应高
莫逆
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State Grid Corp of China SGCC
North China Electric Power Research Institute Co Ltd
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North China Electric Power Research Institute Co Ltd
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Abstract

The invention provides a corrosion detection method for a grounding net, as well as a system. The method comprises the steps as follows: the corrosion potential of detected grounding net metal is measured, constant current step signals are applied to the detected grounding net metal, and the constant current step response signals are collected; the wavelet filter treatment is performed to the collected grounding net soil corrosion electrochemical detection data; and the corrosion electrochemical parameter analysis processing is performed to the grounding net soil corrosion electrochemical detection data after the wavelet filter treatment, thereby generating the grounding net soil corrosion detection result. The grounding net corrosion status is detected accurately and conveniently by the electrochemical detection method.

Description

A kind of ground net corrosion detection method and system
Technical field
The present invention about having used the ground net corrosion state inspection of Electrochemical Detection, is a kind of ground net corrosion detection method and system particularly about generating plant and grounding net of transformer substation etch state detection technique concretely.
Background technology
The grounded screen of generating plant and transformer station is the critical facility that ensures the power system security reliability service.Because grounded screen is laid in usually greater than 0.6 meter subsurface, both cannot see, and does not have monitoring arrangement again, therefore after grounded screen put into operation, how detecting the ground net corrosion situation effectively under the condition of not excavating was problem demanding prompt solution.
Usually the corrosion of grounded screen makes the earth conductor cross section reduce, and severe patient even disconnection cause aspects such as the impedance ground value of grounded screen or the thermally-stabilised cross section of earth conductor not meet relevant rules thus.With this understanding, when system's single phase ground fault fault, the operation of equipment lost territory can take place on the one hand, cause device housings or base current potential to raise, and noble potential can be invaded the secondary switch board or be sealed in main control room along secondary line, this will cause the secondary circuit scaling loss, even cause that the secondary circuit plate burns out in flakes; On the other hand, the earth potential that causes short-circuit current to go into the place earth mat raises, and human casualty accident can take place.This shows that the fault of grounded screen has been the major hidden danger of safe operation of power system, the breakpoint of diagnosis earth mat and the corrosion situation of earth mat have become key subjects of power industry.
Generating plant and grounding net of transformer substation measurement scheme mainly comprise in the prior art:
(1) grounding resistance measurement: if the Resistance of Grounding Grids value is too high, grounded screen can not be brought into play should effect, and the measurement of stake resistance is to estimate grounded screen whether to meet the important means that rules require.For for many years grounded screen of operation, most of stake resistances do not meet the rules regulation, have plenty of because seriously corroded causes, have only by excavation and check the degree that it is corroded, this inspection corroding method has blindness, and workload is big, speed is slow, and is subjected to the restriction of on-the-spot operation.
(2) touch voltage and step voltage are measured: touch voltage and step voltage are to weigh the important indicator of grounded screen security, while is according to the Changing Pattern of step voltage, can find the position that grounded screen is former because of corrosion etc. thereby fracture takes place, the earth mat corrosion section of fracture takes place but it can not find heavy corrosion has taken place.
(3) ground net corrosion and breakpoint physical diagnosis method: this method can be surveyed voltage or resistance measurement value between the node according to earth mat, use suitable computing method, calculate the actual resistance of each section conductor, it is compared with nominal value, and judge according to certain threshold value whether the earth mat conductor has the situation of fracture or corrosion to exist, and Fig. 1 is the measuring principle figure of this detection method.This method requires accurately to know the structure of earth mat, definite mathematical model is proposed on this basis, according to of the data point analytical calculation of this mathematical model to measuring, can draw the actual resistance of each section earth mat conductor, this shows that the factor that influences this method measurement result accuracy is more, and it still has certain limitation to the corrosion diagnosis that moves the net of once visited place for many years.
Because the electrochemical nature that the grounded screen material corrodes in soil, its etch state can characterize with the electrochemical characteristic parameter.To galvanic corrosion, go back available current density usually and represent corrosion speed.In the electrochemical metal corrosion process, the metal that is corroded is as anode, oxidation reaction takes place and constantly dissolved, discharges electronics simultaneously.The electron amount that discharges is many more, that is the electric weight of output is many more, means that metal is much dissolved.Therefore, obviously and between the meltage of metal electrode there is quantitative relation in the electric weight of exporting on the metal electrode, and this quantitative relationship is exactly a Faraday's law.According to Faraday's law, can calculate the amount of dissolving metal by the electric weight that passes through on the electrode.Different electrochemical characteristic parameters can characterize different etch states, for example can estimate the size of metal pitting resistance with disruptive potential, and current potential is low more, and corrosion stability is poor more.The Electrochemical Measurement Technology of metal erosion speed has polarization resistance technology, transient state linear polarization technique, charging curve technology and coulostatic method etc.Adopt electrochemical techniques such as linear polarization or AC impedance can measure electrochemical parameters such as the polarization resistance of grounded screen carbon steel material, corrosion current, but will finish the in-situ corrosion Electrochemical Detection of grounded screen carbon steel material, must solve following two problems:
(1) the current limliting problem of electrochemical corrosion measurement sensor: traditional galvanochemistry three electrode measurement systems are difficult to accurately measure earth mat corrosion of metal state, because a certain section earth mat metal of prediction amount is not an independently electrode, it and whole earth mat metal link together, therefore the polarization current that is added on the earth mat metal by auxiliary electrode can't only be confined on measured this section earth mat metal, the uncertainty of polarized earth mat metallic area, will introduce bigger error in the calculating of corrosion electric current density, Fig. 2 is traditional galvanochemistry three electrode measurement systematic survey principle schematic.The corrosion electrochemistry that therefore will be grounded the net carbon steel material detects, and at first will solve the current limliting problem of electrochemical corrosion measurement sensor.
(2) generating plant, transformer station and transmission route survey environment are to the interference problem of measuring system: exist the stray current that exists in many and strong undesired signal and the soil that the response signal of Electrochemical Measurement Technology is had very strong interference in test environment generating plant, transformer station and the transmission line of electricity, sometimes even fully flood real signal, the response signal signal to noise ratio (S/N ratio) that obtains is very low, can't carry out data analysis.
Chinese patent 99109622.3 disclosed " diagnostic method of transmission transformer station ground net corrosion and breakpoint and measurement thereof, diagnostic system ", Chinese patent 01216711.8 disclosed " high precision soil corrosion measurement device " and Chinese patent application 200510012656.6 disclosed " generating plant, transformer station's large-scale grounding network detection technique and detection system thereof " can be used as prior art of the present invention and are herein incorporated.
Summary of the invention
The invention provides a kind of ground net corrosion detection method and system,, accurately and easily the grounded screen corrosion condition is detected by electrochemical detection method in order to gather grounded screen soil corrosion Electrochemical Detection data.
Technical scheme of the present invention is:
A kind of ground net corrosion detection method said method comprising the steps of: measure tested grounded screen corrosion of metal current potential; Tested grounded screen metal is applied the continuous current step signal, gather the continuous current phase step response signals of grounded screen soil corrosion; Generate grounded screen soil corrosion Electrochemical Detection data according to described tested grounded screen corrosion of metal current potential and continuous current phase step response signals; The grounded screen soil corrosion Electrochemical Detection data that generate are carried out wavelet filtering to be handled; Grounded screen soil corrosion Electrochemical Detection data after the wavelet filtering processing are carried out corrosion electrochemistry parameter dissection process, generate the ground net corrosion testing result.
A kind of ground net corrosion detection system, described system comprises: sensor, be used for tested grounded screen metal is applied the continuous current step signal, gather the continuous current phase step response signals of grounded screen soil corrosion; The galvanochemistry comprehensive test device, be used to measure tested grounded screen corrosion of metal current potential, output continuous current step signal is given described sensor, and receives the continuous current phase step response signals that described sensor transmits, and generates grounded screen soil corrosion Electrochemical Detection data; The wavelet filtering unit is used for that the described grounded screen soil corrosion Electrochemical Detection of gathering is detected data and carries out the wavelet filtering processing; The charging curve resolution unit is used for the grounded screen soil corrosion Electrochemical Detection potential response signal after the wavelet filtering processing is carried out corrosion electrochemistry parameter dissection process, generates the ground net corrosion analysis result.
Beneficial effect of the present invention is: can effectively detect the ground net corrosion electrochemical parameter by described electrochemical sensor, make real being applied in the ground net corrosion detection of electrochemical measuring technique, and then ground net corrosion electrochemical signals application continuous current transient response technology to detecting, measured the potential response curve of corrosion system, response signal is behind ground net corrosion Electrochemical Detection wavelet filtering, parse the polarization resistance of tested grounded screen metal by the electrochemical parameter charging curve, electrochemical parameters such as electric resistance of soil, make under the situation that does not have a power failure and earth mat is not excavated, simple, record earth mat corrosion of metal state quickly.
Description of drawings
Fig. 1 is the measuring principle figure of prior art;
Fig. 2 is the galvanochemistry three electrode measurement systematic survey principle schematic of prior art;
Fig. 3 is the system architecture diagram of electrochemical sensor embodiment of the present invention;
Fig. 4 is a wavelet filtering modular program process flow diagram of the present invention;
Fig. 5 is a charging curve parsing module process flow diagram of the present invention;
Fig. 6 is the synoptic diagram of cylindrical shell of the present invention;
Fig. 7 is the sectional view of electrochemical sensor embodiment of the present invention;
Fig. 8 is the sectional view of tapered front end embodiment of the present invention;
Fig. 9 is the synoptic diagram of electrochemical sensor embodiment of the present invention;
Figure 10 is in the discrete wavelet decomposable process during self-adaptation-frequency window synoptic diagram;
Figure 11 is a signals and associated noises wavelet decomposition principle schematic;
Figure 12 is the runnable interface of wavelet filtering program module;
Figure 13 is the runnable interface of charging curve parsing module.
Embodiment
Below in conjunction with description of drawings the specific embodiment of the present invention.Electrochemical sensor of the present invention comprises: cylindrical shell, and described cylindrical shell has tapered front end, and the cone top part of described tapered front end has metering hole (as shown in Figure 6); Contrast electrode, described contrast electrode is arranged in the described cylindrical shell, and detects the corrosion potential of tested metal in soil by described metering hole; Auxiliary electrode, described auxiliary electrode is arranged in the described cylindrical shell, and constitutes the galvanic circle with soil, tested grounded screen metal.
Shown in Fig. 7,8, described cylindrical shell comprises: insulation column body 504, metal tapered front end 509 and insulation emit 503; Wherein, the cone top part of described metal tapered front end 509 has metering hole; Be dismountable the connection between described metal tapered front end 509 and the described insulation column body 504; Described insulation emit 503 with described insulation column body 504 between for dismountable the connection.
Described contrast electrode comprises: insulative tubular cavity 517 is used to deposit copper-bath 516; Infiltration fills in 513, is used for an end of the described insulative tubular cavity 517 of shutoff, and described copper-bath 516 oozes out by described infiltration plug 513; Airtight plug 506 is used for the other end of the described insulative tubular cavity 517 of shutoff; Copper conductor 508, described copper conductor 508 inserts the copper-bath 516 in the described insulative tubular cavity 517, and draws by described airtight plug 506.
Described auxiliary electrode comprises: metal tapered electrode 511, this metal tapered electrode 511 axially have a perforation; Auxiliary electrode terminal 512; Insulation course 510 is used to make metal tapered electrode 511 and 509 insulation of metal tapered front end; Contrast electrode lead-in wire 501 is connected with described copper conductor 508; Auxiliary electrode lead-in wire 502 is connected with described auxiliary electrode terminal 512.Has the space that can hold soil between described metering hole and the infiltration plug 513.
Contrast electrode lead-in wire 501 is connected with described copper conductor 508; Auxiliary electrode lead-in wire 502 is connected with described auxiliary electrode terminal 512.
Embodiment
Shown in Fig. 8,9, present embodiment provides the condition detecting system of the ground net corrosion with electrochemical sensor, and electrochemical sensor wherein is called as aperture current-limiting type corrosion electrochemistry sensor, is called for short aperture current limliting sensor.
One, aperture current limliting sensor comprises:
1) as the overcoat (plain carbon steel system) of tapered front end;
2) insulation course 501 (poly-tetrafluoro adhesive tape);
3) be positioned at the screw (514,515) of the outer M2.5 that puts, and join respective screws with the fixed plastics pipe so that dismountablely be connected (also can adopt and be threaded) with the column body 504 that insulate;
4) diameter as insulation column body is the polyvinyl chloride pipe of 15mm;
5) auxiliary electrode (1Cr13SS);
6) contrast electrode (Cu/CuSO4);
7) as the screw of auxiliary electrode terminal, join screw, so that draw the auxiliary electrode lead.
Two, the making of contrast electrode:
With the vinyl tube of a diameter 3.5mm, an end is with cork jam-pack (or osmotic ceramic plug), saturated CuSO4 solution in the pipe is not outflowed as far as possible and can conducting well guarantee the accurate of potential measurement.Inject saturated CuSO4 solution in the plastic tube, and put into the saturability that a small amount of CuSO4 crystal guarantees solution, insert the fine copper silk of removing oxide oil removing grease removal, the other end of plastic tube clogs with stopper.
Three, the making of auxiliary electrode:
Auxiliary electrode only plays the conducting electric current, and anti-corrosion metal or alloy can both meet the demands, and all can make auxiliary electrode as platinized platinum and stainless steel.Consider the shape of auxiliary electrode (shown in Fig. 7,8,9), auxiliary electrode is made by stainless steel bars processing.One end is processed into and round table-likely cooperates with overcoat, and frustum cone side tightly wraps with poly-tetrafluoro adhesive tape, prevents and the conducting of carbon steel overcoat.The other end processes a screw and joins corresponding screw retention lead and goes between as auxiliary electrode.At the center of whole auxiliary electrode is the through hole of a diameter 3.5mm, inserts contrast electrode (as shown in Figure 7).
Four, the making of protection overcoat and probe moulding:
Shown in Fig. 7,8, as the protection overcoat of the taper of metal tapered front end 509, its front end is the aperture of restriction electric current, hole diameter 5mm.The whole protecting overcoat is made by carbon steel.
The front end of polyvinyl chloride plastic pipe is inserted in contrast electrode and auxiliary electrode assembling back, and contrast electrode lead-in wire and auxiliary electrode lead-in wire are drawn by inside of plastic tubes.Load onto the protection overcoat, fix with screw and polyvinyl chloride plastic pipe.
As shown in Figure 3, adopt potentiostat as the galvanochemistry comprehensive test device, the contrast electrode lead-in wire is connected with potentiostat with the auxiliary electrode lead-in wire, send the electric signal of gathering to described potentiostat, described potentiostat also can connect a notebook computer.Wherein claim potentiostat to be used to measure tested grounded screen corrosion of metal current potential; Tested grounded screen metal is applied the continuous current step signal, gather the continuous current phase step response signals of grounded screen soil corrosion; Generate grounded screen soil corrosion Electrochemical Detection data according to described tested grounded screen corrosion of metal current potential and continuous current phase step response signals.
Wavelet filtering program module and charging curve analysis program module are installed in notebook computer.Wherein:
Five, the establishment of wavelet filtering program module:
Wavelet analysis is the breakthrough of Fourier analysis method, is up-to-date time frequency analyzing tool.
(1) definition of small echo, wavelet transformation and condition:
If Ψ (t) ∈ is L 2(R), its Fourier is transformed to When Satisfy enabled condition (Admissible Condition)
C &Psi; = &Integral; R | &Psi; ^ ( &omega; ) | 2 | &omega; | d&omega; < &infin; - - - ( 1 )
The time, claim that then Ψ (t) is a basic small echo or female small echo (Mother Wavelet).Generating function Ψ (t) after flexible and translation, just can be obtained a little wave train.Here, L 2(R) represent square-integrable real number space, i.e. the limited signal space of energy.For continuous situation, little wave train is:
&Psi; a , b ( t ) = 1 | a | &Psi; ( t - b a ) , a , b &Element; R ; a &NotEqual; 0 - - - ( 2 )
In the formula, a is a contraction-expansion factor, and b is a shift factor.
For discrete case, little wave train is:
&Psi; j , k ( t ) = 2 - j 2 &Psi; ( 2 - j t - k ) , j , k &Element; Z - - - ( 3 )
From the definition of small echo as can be known, wavelet function not only requires to have certain concussion, and promptly it is comprising certain frequecy characteristic, but also requires to have certain limitation, be that it is constantly equal to 0 or converge on 0 soon on an interval, this also is the reason that Ψ (t) is called small echo.Small echo is exactly one little " wave " of carrying it through to the end.The central role of small echo is to represent function or signal among the L2 (R) with these small echos and flexible and translation thereof.
(2) wavelet multiresolution analysis method:
Multiresolution analysis is one of most important notion in the wavelet analysis, and it represents from many resolutions of the height of function space research function, is radio-frequency component under a low-frequency component and the different resolution with a function representation.Figure 10 is in the discrete wavelet decomposable process during self-adaptation-frequency window synoptic diagram, the discrete wavelet component all has performance on different scale, the time frequency window shape is adjusted automatically with different sub-bands, j value large scale is thin, corresponding Wavelet Component has showed certain sub-band signal, higher and the frequency band broad in its frequency center, thin narrow time frequency window just in time help this front end sub-band signal is done partial analysis.Same j value than hour, corresponding Wavelet Component has showed another kind of sub-band signal, its frequency center is low and frequency band is narrower, flat time frequency window just in time helps the low frequency end sub-band signal is done partial analysis.Wavelet analysis has higher frequency resolution and lower temporal resolution in low frequency part, have higher temporal resolution and lower frequency resolution at HFS, thereby can effectively information extraction from signal, by calculation functions such as flexible and translations function or signal are carried out multiscale analysis (Multiscaie Analysis), make wavelet transformation have adaptivity signal.
(3) wavelet analysis is applied to the principle that signal noise silencing is handled:
Useful signal is usually expressed as low frequency signal or some signals more stably, and noise signal then is usually expressed as high-frequency signal.So the de-noising process can be handled as follows: at first signal is carried out wavelet decomposition and (as carry out three layers of decomposition, decomposable process as shown in figure 11), then noise section is generally comprised within cD1, cD2, among the cD3, thereby, can handle wavelet coefficient with forms such as door threshold values, then signal is reconstructed the purpose that promptly can reach de-noising.Purpose to signal s (i) de-noising is exactly the noise section that will suppress in the signal, thereby recovers actual signal f (i) in s (i).
In general, the de-noising process of one-dimensional signal can be divided into three steps and carries out:
(a) wavelet decomposition of one-dimensional signal.Select the level N of a small echo and a definite wavelet decomposition, then signal s is carried out N layer wavelet decomposition.
(b) threshold value quantizing of wavelet decomposition high frequency coefficient.To the 1st each floor height frequency coefficient, select a threshold value to carry out the soft-threshold quantification treatment to the N layer.
(c) reconstruct of one dimension small echo.According to the low frequency coefficient of the N layer of wavelet decomposition with through the 1st layer of high frequency coefficient after the quantification treatment, carry out the wavelet reconstruction of one-dimensional signal to the N layer.In the present embodiment N can be in 1,2,3 value.
(4) wavelet noise of grounded screen metal continuous current transient test potential response signal and corrosion potential signal is handled:
Utilize the ultimate principle of wavelet noise, establishment ground net corrosion Electrochemical Detection wavelet filtering software on LabVIEW 7.0 and Signal ProcessingToolset 7.0.1 software platform, the Filtering Processing of realization electrochemical response signal.
(5) runnable interface of wavelet filtering program module
As shown in figure 12, left part is data layout and wavelet parameter option, wherein,
Data layout: the file of wavelet filtering routine processes separates with Tab between row and the row for comprising the txt file of current potential, electric current, times three column data (E-I-t) or time, current potential two column data (t-E).
The figure that selection will show: choose this check box, can select current potential or electric current that the time is mapped, program is only carried out filtering to the data of selecting.Be defaulted as current potential-time (E-t).
Preserve when withdrawing from: choose this check box, can eject the dialog box of preserving data when withdrawing from.
Wavelet parameter:
1) decompose the number of plies: the number of plies during wavelet decomposition, scope be from 1 to log2N (N is a sampling number), and it is high more to decompose the number of plies, and curve is flat more, information dropout many more.Be defaulted as 1.
2) small echo kind: the kind of wavelet basis during wavelet decomposition.Be defaulted as the Haar small echo.
Be positioned at Figure 10 center Screen position that takes over, occupy most of interface.Horizontal ordinate is the time, and ordinate is current potential or electric current, and the scale and the unit of coordinate axis change automatically according to data.The control in the upper right corner can be adjusted the form of curve map.The control of below is used on curve map pointwise and reads coordinate.
Wavelet filtering program module flow process as shown in Figure 4, wherein:
With continuous current step potential response signal and corrosion potential signal input grounding net soil corrosion Electrochemical Detection potential response signal wavelet decomposition module, this grounded screen soil corrosion Electrochemical Detection potential response signal wavelet decomposition module, be used to adopt the Haar small echo that the Electrochemical Detection data that generate are carried out limited orthogonal wavelet and decompose, promptly continuous current step potential response signal and corrosion potential signal are carried out wavelet decomposition;
Wavelet decomposition high frequency coefficient threshold value acquisition module is used at each different wavelet decomposition level all there not to be inclined to one side estimating noise threshold size; The threshold denoising module is used for will carrying out inverse transformation to the coefficient zero setting of the discrete details of wavelet decomposition at different levels less than threshold value to the wavelet coefficient of handling greater than the coefficient storage of threshold value; Promptly to continuous current step potential response signal and corrosion potential signal wavelet decomposition high frequency coefficient threshold value quantizing;
Electrochemical Detection potential response signal wavelet reconstruction module is used to reconstruct the Electrochemical Detection data through after the denoising, promptly to the wavelet reconstruction of signal, uses the low frequency coefficient and the high frequency coefficient after the quantification treatment of wavelet decomposition to carry out wavelet reconstruction.
Six, charging curve analysis program module
As shown in Figure 5, be the flow process of charging curve parsing module, in this module:
The initial value setting module: be used to set an initial value, the charging curve equation pressed platform labor series expansion, become linear equation, with least square method obtain separate after, iteration correction initial value again again is up to the requirement of satisfying error.
The principle of work of charging curve resolution unit is as follows:
The charging curve equation: E = IR l + IR P ( 1 - e - t R P C d ) - - - ( 1 , )
Obtain equation after the arrangement distortion: ln (W-E i)-U=Xt i: (2 ')
In the formula: W=I (R L+ R P) U=lnIR P X = - R P C d
An if initial value W 0, W=W 0+ Z (Z is an error) substitution (2 ') formula gets;
ln[(W 0+Z)-E i]-U=Xt i:(3’)
(3 ') formula is pressed platform labor series expansion, omits high-order term, put in order
u+t iX+Q iZ=y i(4’)
In the formula: y i=ln (W 0-E i) Q i = - 1 W 0 - E i
Adopt least square method to find the solution charging curve equation (4 '), try to achieve the numerical value of U, X, Z, W=W 0+ Z substitution is recomputated, and iteration is up to R P, Z, X variation enough little, can calculate R L, R P, C dValue.Wherein:
R P = e u I &CenterDot; S
R L = W 0 + Z I - R P
As seen by the curvilinear equation formula of Electrochemical Detection data and continuous current phase step response signals:
E = IR l + IR P ( 1 - e - t R P C d )
Parse and comprise polarization resistance R P, interface capacitance C d, dielectric resistance R 1At interior electrochemical parameter.
Figure 13 is the runnable interface of charging curve analysis program, and left part is that data layout and parameter are provided with option, and right part is the operation analysis result.
Data layout: the file that the charging curve analysis program is handled separates with tab between row and the row for comprising the txt file of current potential, electric current, times three column data (E-I-t) or time, current potential two column data (t-E).
The figure that selection will show: can select current potential or electric current that the time is mapped, program is only carried out match to the data of selecting.Be defaulted as current potential-time (E-t).
Preserve when withdrawing from: choose this check box, can eject the dialog box of preserving data when withdrawing from, data are saved to comprising the txt file of current potential, electric current, times three column data, no line of text head.Be defaulted as and choose.
Parameter is provided with:
Δ I/A or Δ E/V: electric current or potential step value, set according to experiment parameter.Be defaulted as current step 10 μ A.
Current potential magnitude or electric current magnitude: the magnitude of current potential or current values can exert an influence to fitting result, selects suitable magnitude to obtain optimum fit curve.Be defaulted as automatically.
Sampling resistor: this control only be " t-E (ZF-10) " and the figure that shows appearance when being " E-t " at data layout.Set sampling resistor according to experiment parameter, program is converted into current value with the current potential that ZF-10 gathers.Be defaulted as 10k Ω.
Initial row: the initial row of processed data segment.Default value 0 expression is since first row.
End line: the end line of processed data segment.Default value 0 is represented to finish to N capable (N is a sampling number).
The initial value point moment: in the roughly moment that step takes place, this numerical value need be slightly larger than the moment that step takes place.Be defaulted as 5s.
Wavelet decomposition reconstruction options card:
Filtering-choose this check box, program is carried out filtering to data earlier, resolves with the filtering result again.Be defaulted as and do not select.
The number of plies when decomposing the number of plies-wavelet decomposition, scope be from 1 to log2N (N is a sampling number), and it is high more to decompose the number of plies, and curve is flat more, information dropout many more.Be defaulted as 1.
The kind of wavelet basis during small echo kind-wavelet decomposition.Be defaulted as the Haar small echo.
Charging curve resolution choices card:
Whether filtering-demonstration has carried out Filtering Processing.
The Ecorr-corrosion potential.
EO-response current potential initial value.
E ∞-response current potential steady-state value.
Initial value during the match of R10-electric resistance of soil.
Initial value during the match of RpO-polarization resistance.
Be positioned at Figure 11 center Screen position, occupy most of interface.Horizontal ordinate is the time, and ordinate is current potential or electric current, and the scale and the unit of coordinate axis change automatically according to data.Curve after demonstration raw data curve and the filtering in wavelet decomposition reconstruction options card, curve and matched curve after the demonstration filtering in charging curve resolution choices card.The control in the upper right corner can be provided with the form of curve map.
Analysis result:
R1-electric resistance of soil analysis result.
Rp-polarization resistance analysis result.
Cd-interface capacitance analysis result.
τ-time constant analysis result.
Square error between MSE residual error-matched curve and the raw data.
MSE = 1 n &CenterDot; &Sigma; i = 0 n - 1 ( f i - y i ) 2
Wherein: fi is the fitting data point, and yi is a raw data points, and n is for counting.
Operation steps:
1. wavelet filtering program
Set " document format data ", according to the choice of equipment that obtains data.The ZF-10 data acquisition unit is selected " t-E (ZF-10) ", and 2263 select " E-I-t (2263) ", and DAQ selects " E-I-t (DAQ) ".Set in " figure that will show ", " E-t " figure is selected in corrosion potential test or continuous current test, and program is carried out filtering to potential data; " I-t " figure is selected in the constant potential test, and program is carried out filtering to current data.Read in data, click " opening data file " button, in the dialog box that ejects, select to open the data file of a .txt form.If successfully read in data, path that can display file in the text box of button top, otherwise can show and do not read in data.Wavelet parameter is set, adopts default setting to get final product generally speaking.If filter effect decomposes the number of plies and changes different types of wavelet basis to obtain desirable filter effect by undesirable can suitably increasing.Withdraw from, click " withdrawing from " button and quit a program, preserve filtered data if desired, then choose " preserving when withdrawing from ".Operation once more, small arrow button (" Run " button) appears in the upper left corner, back that quits a program, and clicks this button and gets final product rerun routine, and the step above repeating is carried out data processing once more.
2. charging curve analysis program
Set " document format data ".According to the choice of equipment that obtains data.The ZF-10 data acquisition unit is selected " t-E (ZF-10) ", and 2263 select " E-I-t (2263) ", and DAQ selects " E-I-t (DAQ) ".Set in " figure that will show ", " E-t " figure is selected in the continuous current test, and program is carried out match to potential data; " I-t " figure is selected in the constant potential test, and program is carried out match to current data.Set the step amplitude of pumping signal, the continuous current test shows " E-t " figure, sets " Δ I/A "; The constant potential test shows " I-t " figure, sets " Δ E/V ".Read in data, click " opening data file " button, in the dialog box that ejects, select to open the data file of a .txt form.If successfully read in data, path that can display file in the text box of button top, otherwise can show and do not read in data.Filtering, enters " wavelet decomposition reconstruct " tab if phase step response signals is submerged in the noise, chooses " filtering " check box earlier raw data to be carried out filtering.If filter effect decomposes the number of plies and changes different types of wavelet basis to obtain desirable filter effect by undesirable can suitably increasing.Set " electric current magnitude " or " current potential magnitude ", adopt default setting (auto) to get final product generally speaking.If matched curve and raw data exist than large deviation, can attempt changing magnitude obtaining optimum fit curve, the principle that changes magnitude be make data under this magnitude greater than 1.The selected data segment that needs processing adopts default setting (" initial row " and " end line " all is made as 0) to get final product generally speaking.Change as need, setting " initial row " is V * ts, and " end line " (V is a sampling rate, is generally 20 for V * te; Ts is the initial moment, and 0≤ts<step constantly; Te is the finish time, the step moment<te≤total sampling time).The roughly moment that step takes place is set, adopts default setting (5 seconds) to get final product generally speaking.Change as need, the moment tp that visual in the drawings step takes place sets " step constantly<" and is slightly larger than tp.Withdraw from, click " withdrawing from " button and quit a program, preserve filtered data if desired, then choose " preserving when withdrawing from ".Operation once more, small arrow button (" Run " button) appears in the upper left corner, back that quits a program, and clicks this button and gets final product rerun routine, and the step above repeating is carried out data processing once more.
Seven, grounded screen band iron position ground penetrating radar detects:
The grounded screen metal is carried out in-situ corrosion when detecting, require measured sensor to insert in measured grounded screen band iron top or near the soil, so need to determine the Position Approximate of measured metal before the earth mat corrosion measurement.Ground penetrating radar utilizes the principle of reflection of high-frequency electromagnetic pulsating wave to realize surveying purpose, the intensity of its reflected impulse signal is not only relevant with the ripple degree of absorption of propagation medium, and it is relevant with the wave reflection coefficient that is penetrated medium interface, the big person of electromagnetic parameter difference of both sides medium, reflection coefficient is also big, and the energy of same reflection wave is also big.It is the electromagnetic waves of tens of megahertzes (MHz) to the kilo-mega cycles per second wave band that ground penetrating radar is utilized dominant frequency, with broadband short pulse form, being sent to undergroundly by ground by antenna emitter (T), returning ground behind the boundary reflection on underground purpose body or stratum, is that radar antenna receiver (R) is accepted.When electromagnetic wave is propagated in medium, its path, electromagnetism intensity and waveform will with by medium electrically and geometric shape change.Therefore, according to data such as the hourage that receives ripple (also claiming two way travel time), amplitude and waveforms, detectable dielectric structure, construct and bury underground object.According to the detection principle of ground penetrating radar, the embodiment of the invention adopts SIR-2000 type ground penetrating radar instrument.The ground net corrosion detection system is made up of PARSTAT 2263 advanced electro-chemical systems, PowerSuit electrochemical measurement software, aperture current-limiting type corrosion electrochemistry sensor and ground net corrosion Electrochemical Detection software.
In the ground net corrosion condition detecting system that aperture current limliting sensor, potentiostat and notebook computer are formed, aperture current limliting sensor is used to gather grounded screen soil corrosion Electrochemical Detection potential response signal; Potentiostat is used to receive the Electrochemical Detection potential response signal that described sensor transmits, and the control electromotive force changes in time, obtains volt-ampere curve or electrode impedance data; The wavelet filtering program is used for that the described grounded screen soil corrosion Electrochemical Detection potential response signal of gathering is carried out wavelet filtering and handles; The charging curve analysis program is used for the grounded screen soil corrosion Electrochemical Detection potential response signal after the wavelet filtering processing is carried out corrosion electrochemistry parameter dissection process, generates the ground net corrosion analysis result.The polarization current of described aperture current limliting sensor flows to working electrode by aperture.Described grounded screen soil corrosion Electrochemical Detection potential response signal comprises: corrosion potential response signal and continuous current transient test potential response signal.
Described electrochemical sensor is enclosed in cylindrical shell with auxiliary electrode, and polarization current can only flow to working electrode by metering hole, has realized the metering function of sensor.By ground net corrosion Electrochemical Detection sensor, the potential response curve of corrosion system of having used continuous current transient response commercial measurement, response signal is behind ground net corrosion Electrochemical Detection wavelet filtering, parse the electrochemical parameter such as polarization resistance, electric resistance of soil of tested grounded screen metal by the electrochemical parameter charging curve, make under the situation that does not have a power failure and earth mat is not excavated, record earth mat corrosion of metal state simply, quickly.
Above embodiment only is used to illustrate the present invention, but not is used to limit the present invention.

Claims (10)

1. ground net corrosion detection method wherein, said method comprising the steps of:
Measure tested grounded screen corrosion of metal current potential;
Tested grounded screen metal is applied the continuous current step signal, gather the continuous current phase step response signals of grounded screen soil corrosion;
Generate grounded screen soil corrosion Electrochemical Detection data according to described tested grounded screen corrosion of metal current potential and continuous current phase step response signals;
The grounded screen soil corrosion Electrochemical Detection data that generate are carried out wavelet filtering to be handled;
Grounded screen soil corrosion Electrochemical Detection data after the wavelet filtering processing are carried out corrosion electrochemistry parameter dissection process, generate the ground net corrosion testing result.
2. method according to claim 1, it is characterized in that, described tested grounded screen metal is applied the continuous current step signal, the continuous current phase step response signals of gathering the grounded screen soil corrosion comprises: adopt aperture current limliting sensor that tested grounded screen metal is applied the continuous current step signal, and gather grounded screen continuous current phase step response signals, the polarization current of described aperture current limliting sensor flows to tested grounded screen metal by aperture.
3. method according to claim 1, it is characterized in that, described grounded screen soil corrosion Electrochemical Detection data to generation are carried out the wavelet filtering processing and are meant: adopt the Haar small echo that the Electrochemical Detection data that generate are carried out limited orthogonal wavelet and decompose, at each different wavelet decomposition level all there not to be inclined to one side estimating noise threshold size, in the discrete details of wavelet decomposition at different levels less than the coefficient zero setting of threshold value, will be greater than the coefficient storage of threshold value, the wavelet coefficient of handling is carried out inverse transformation, reconstruct through the Electrochemical Detection data after the denoising.
4. method according to claim 1, it is characterized in that described grounded screen soil corrosion Electrochemical Detection data after wavelet filtering is handled are carried out corrosion electrochemistry parameter dissection process and are meant: by the curvilinear equation formula of Electrochemical Detection data and continuous current phase step response signals:
E = IR l + IP P ( 1 - e - t R P C d )
Parse and comprise polarization resistance R P, interface capacitance C d, dielectric resistance R 1At interior electrochemical parameter.
5. method according to claim 1 is characterized in that, adopts ground penetrating radar to measure the position of described tested grounded screen metal.
6. a ground net corrosion detection system is characterized in that, described system comprises:
Sensor is used for tested grounded screen metal is applied the continuous current step signal, gathers the continuous current phase step response signals of grounded screen soil corrosion;
The galvanochemistry comprehensive test device, be used to measure tested grounded screen corrosion of metal current potential, output continuous current step signal is given described sensor, and receives the continuous current phase step response signals that described sensor transmits, and generates grounded screen soil corrosion Electrochemical Detection data;
The wavelet filtering unit is used for that the described grounded screen soil corrosion Electrochemical Detection of gathering is detected data and carries out the wavelet filtering processing;
The charging curve resolution unit is used for the grounded screen soil corrosion Electrochemical Detection potential response signal after the wavelet filtering processing is carried out corrosion electrochemistry parameter dissection process, generates the ground net corrosion analysis result.
7. system according to claim 6 is characterized in that, described sensor is meant: aperture current limliting sensor, the polarization current of described aperture current limliting sensor flows to tested grounded screen metal by aperture.
8. system according to claim 6 is characterized in that, described wavelet filtering unit comprises:
Grounded screen soil corrosion Electrochemical Detection potential response signal wavelet decomposition module is used to adopt the Haar small echo that the Electrochemical Detection data that generate are carried out limited orthogonal wavelet and decomposes;
Wavelet decomposition high frequency coefficient threshold value acquisition module is used at each different wavelet decomposition level all there not to be inclined to one side estimating noise threshold size;
The threshold denoising module is used for will carrying out inverse transformation to the coefficient zero setting of the discrete details of wavelet decomposition at different levels less than threshold value to the wavelet coefficient of handling greater than the coefficient storage of threshold value;
Electrochemical Detection potential response signal wavelet reconstruction module is used to reconstruct the Electrochemical Detection data through after the denoising.
9. system according to claim 6 is characterized in that, described charging curve resolution unit comprises: the electrochemical parameter parsing module is used for the curvilinear equation formula according to Electrochemical Detection data and continuous current phase step response signals:
E = IR l + IR P ( 1 - e - t R P C d )
Parse and comprise polarization resistance RP, interface capacitance Cd, dielectric resistance R1 is at interior electrochemical parameter.
10. system according to claim 6 is characterized in that, described system also comprises: ground penetrating radar is used to measure the position of described tested grounded screen metal.
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