CN1028774C - New techhique for protection against stray currents - Google Patents

Abstract

In the prior art for the elimination of stray current and the power transmission protection with an anti-corrosion instrument of underground metal structures in regions with the stray current, the underground metal structures are always perforated in a large area in one to three years to cause the leakage of transmitted media to generate poisoning accidents and cause the serious damage such as explosions, etc. By using the current distributing technology and the anti-corrosion instrument of the present invention, the underground metal structures in the regions with the stray current can be controlled in the interval of the protection potential of the regions with the stray current through a waveform controller so as to prolong the service life of the metal structures by more than twice. In company with the development of electrified railways and the industry of petroleum, chemical engineering, communication and electricity, the present invention can be applied more extensively, and more economic benefit can be generated.

Description

New techhique for protection against stray currents

The invention belongs to the soil corrosion field of underground metal structures, particularly stray current is got rid of and protection technology.

In the middle of general soil corrosion, the corrosion speed of stray current is the fastest, and metal structures such as underground metal pipeline, cable are bored a hole with regard to occurrence of large-area at 1-3.Like this, underground metal structures are incurred loss, and will cause the leakage of delivery medium, breaks in production is poisoned, serious accident such as set off an explosion, even can cause above ground structure to cave in.

In the past, the underground metal pipeline of scattered electricity area adopted the way of direct electric drainage, promptly was that the positive column of metal pipe line is directly received on the negative regression line of direct current interfering sources such as electric iron or DC substation, thereby realized the cathodic polarization to drainage point.But this polarization is often used the flow point current potential and was produced negatively, and the potential fluctuation amplitude is very big, the control difficulty.Simultaneously, this current drainage must just can be carried out near places of interfering source such as electric iron or DC substations at drainage point, and therefore significant limitation is arranged.

In addition; the scattered electricity area underground utilities adopt anti-corrosion meter to protect; burying one group of supplementary anode t underground from h place, protected pipeline a distance; join with the positive pole of lead this group supplementary anode t and anti-corrosion meter F; the negative pole of anti-corrosion meter is received on the O of metal pipe line confluence, with monitoring instrument monitoring all fronts pipe-to-soil potential waveform, but facts have proved that this method not only can not make protected pipeline submit in scattered electricity area protection potential interval; strengthen its potential fluctuation amplitude on the contrary, thereby quickened corrosion.

The method for removing that the purpose of this invention is to provide a kind of stray current promptly adopts the current drainage simultaneously of negative and positive polar region and DC substation rationally is set and reduces stray current.

Another object of the present invention provides a kind of underground metal structures safety guard in strays area that comprises existing anti-corrosion meter, adopts a kind of wave forms adaptive controller to improve original protector.

A further object of the present invention provides a kind of adjustment method of waveform adaptive controller, makes above-mentioned protector obtain best protection effect.

According to stray current elimination technique of the present invention, allow to beat under the condition of current drainage ground connector in geology and environment, the negative and positive polar region is carried out the spy simultaneously add the processing of intensity level anti-corrosion insulation, also beat the current drainage ground connector in the negative electrode area, make both stake resistance approximately equals, its size determines by standard, thereby overcame negative potential.Owing to beat the current drainage ground connector simultaneously in anode and cathode, this has just significantly reduced the geographic corrosion current of anode and cathode.

According to the present invention, build the power DC substation of usefulness of electric locomotive the position of railway two ends in, the total load current in the track is gone to zero, thereby make the stray current in the invasion pipeline very little, reach and do not reduce that electricity is let out and the purpose that significantly reduces galvanic corrosion.

According to the present invention, in the existing underground metal structures safety guard of being formed by anti-corrosion meter and monitoring voltage table in strays area, n group supplementary anode ground connector t is installed ₁, t ₂..., t _nThe distance of they and protected metal structures is respectively h ₁, h ₂..., h _nAnd the satisfied 400～500m 〉=h that concerns ₁＞h ₂＞... h _n; Set up a waveform adaptive controller, the output cathode of anti-corrosion meter is connected on the input terminus y of this waveform adaptive controller, the output terminal of this waveform adaptive controller is connected on respectively on each supplementary anode ground connector.

According to waveform adaptive controller of the present invention, n bar branch road is arranged, every branch road has a varistor R respectively ₁, R ₂..., R _n, and be connected in series a reometer A ₁, A ₂..., A _n, its output terminal is the output terminal of waveform adaptive controller, and the input terminus of n bar branch road is become one, forms the input terminus y of entire controller.

According to underground metal structures safety guard of the present invention, its control method is to adjust each variohm one by one, observes the protection curve that monitoring instrument shows, if this curve drops in this scattered electricity area protection potential interval, debugging finishes; If exceed this interval, change the distance of corresponding supplementary anode ground connector and structures, debug again, in shown protection curve drops on this scattered electricity area guard interval, also can regulate each variohm simultaneously, its method is same as described above.

Adopt current drainage method of the present invention and resist technology, works very well, underground metal pipeline can prolong more than 2 times work-ing life, has tangible economic benefit and social benefit.

Below in conjunction with accompanying drawing the present invention is elaborated.

Fig. 1 is indirect current drainage technical equivalences schematic circuit.

Fig. 2 is an electric railway DC substation layout drawing.

Fig. 3 is an anode and cathode current drainage simultaneously equivalent-circuit diagram.

Fig. 4 utilizes four supplementary anodes to carry out the schematic diagram of device of galvanic protection.

Fig. 5 is pipe ground polarized potential (E)-guard space (L) graphic representation.

Fig. 6 adapts to line debugging figure for waveform.

The equivalent-circuit diagram of indirect current drainage principle as shown in Figure 1.

As shown in the figure, I-is at 2 load circuits of flowing through of railway m, n, A; V _DThe service voltage of-electric iron, V; E ₁-railway m point above earth potential, V; E ₂-railway n point above earth potential, V; R _TThe transmission resistance of-rail, Ω; R _S1-rail m point place stake resistance, Ω; R _S2-rail n point place stake resistance, Ω; R _j-steel pipe influent stream point A place stake resistance, Ω; R _c-steel pipe goes out flow point C place stake resistance, Ω; R _t-m, n point-to-point transmission soil spreading resistance, Ω; R _P-steel pipe goes out flow point C place's current drainage stake resistance, Ω; E ₀2 potential differences of-rail m, n, V, and have:

E ₀＝E ₁-E ₂＝R _T·I;

The strays of E-equivalence corrodes system's current potential, V, and have:

$\mathrm{E\; =}\frac{R_t{\mathrm{·\; E}}_o}{R_{\mathrm{a\; 1}}{\mathrm{+\; R}}_{\mathrm{a\; 2}}{\mathrm{+\; R}}_t}$

R _NThe strays of-equivalence corrodes system's internal resistance, Ω, and have:

R _N＝（R _S1+R _S2）//R _t;

I _jFlow directly into the stray current of steel pipe in the-soil by tube wall from steel pipe A place, A; T _c-flow directly into stray current in the soil, A from steel pipe C place by tube wall; V _j-steel pipe influent stream point earth potential difference, V; V _c-steel pipe goes out flow point earth potential difference, V; K _P-stream discharging system switch; The D-diode.

Through deriving, following seven formula are arranged, promptly only with positive column indirect current drainage principle formula:

$l_{\mathrm{11}}\mathrm{=\; l}{}_{\mathrm{c1}}=\frac{E}{R_N{\mathrm{+\; R}}_1{\mathrm{+\; R}}_c}\mathrm{(1)}$

$V_{\mathrm{11}}=\frac{{\mathrm{ER}}_1}{R_N{\mathrm{+R}}_1{\mathrm{+\; R}}_c}\mathrm{(2)}$

$V_{\mathrm{cl}}=\frac{E}{\frac{R_N{\mathrm{+\; R}}_1}{R_c}\mathrm{+\; 1}}\mathrm{(3)}$

${\mathrm{<figure-callout\; id="12"\; label="I"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">I</figure-callout>}}_{\mathrm{12}}=\frac{E}{R_N{\mathrm{+\; R}}_1\frac{R_c{\mathrm{·\; R}}_p}{R_c{\mathrm{+\; R}}_p}}\mathrm{(4)}$

${\mathrm{<figure-callout\; id="12"\; label="V"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{12}}=\frac{{\mathrm{ER}}_1}{R_2{\mathrm{+\; R}}_2+\frac{R_c{\mathrm{·\; R}}_p}{R_c{\mathrm{+\; R}}_p}}\mathrm{(5)}$

$V_{\mathrm{c2}}=\frac{E}{{\mathrm{［\; (R}}_N{\mathrm{+\; R}}_1\mathrm{)\; /}\frac{R_c{\mathrm{·R}}_p}{R_c{\mathrm{+R}}_p}\mathrm{］\; +\; 1}}\mathrm{(6)}$

$I_{\mathrm{c2}}=\frac{E}{R_N{\mathrm{+\; R}}_1{\mathrm{+\; R}}_c+\frac{R_c}{R_p}{\mathrm{(R}}_N{\mathrm{+\; R}}_1)}\mathrm{(7)}$

Inferior in the formula " 1 ", " 2 " are represented before the current drainage respectively and parameter after the current drainage.

Formula (1)～(3) directly pass in and out stray current in the soil for the pipeline above earth potential of turnover flow point before the current drainage with by tube wall; Public (4)～(7) are corresponding current potential, the electric current of the turnover flow point after the current drainage.Can draw as drawing a conclusion by above-mentioned formula comparison:

1. current drainage can make the pipe-to-soil potential V of positive column _c, the abrasion electric current I _cReduce;

2. to increase and flow point current drainage effect, remove the preservative coat resistance R that increases the turnover flow point _j, R _cCan also reduce current drainage ground connector resistance R greatly outward, _PReducing of current drainage ground connector stake resistance will make influent stream point cathode polarizing current I _jIncrease, this is the negative interaction that can't overcome in the current drainage.Simultaneously, the stake resistance of current drainage ground connector can not infinitely reduce, and turnover flow point anti-corrosion insulation resistance can not infinitely increase, thereby going out flow point corrosion current and voltage can not be zero.Therefore, use the flow point steel pipe and obtain galvanic protection, must carry out cathodic polarization in addition.

3. the measure that reduces the negative interaction of influent stream point is the anticorrosion layer insulating resistance that increases the turnover flow point.

4. reducing strays corrosive basic method is to reduce strays interfering source equivalence corrosion potential E and corrode the internal resistance R of system _NIts method increases the stake resistance of track etc. for strengthening being electrically connected of rail.

5. especially the reasonable Arrangement of DC substation is the important channel of reducing galvanic corrosion.This is one and does not reduce electricity and let out, and reduces the good measure of galvanic corrosion.Its reason is that the load current I in the electric iron is each electric substation's load current sum.The present invention adopts decoration form as shown in Figure 2, and following relational expression is arranged:

I＝I ₁+I ₂

I in the formula ₁, T ₂Be respectively two Z of electric substation ₁, Z ₂Through electric car D ₁, D ₂Load current, and I ₁And I ₂Direction is opposite, the absolute value approximately equal.

, will have the rational position that electric substation is located at the two ends of railway according to the present invention | I ₁| ≈ | I ₂|, and its direction is opposite, thereby I=I is arranged ₁+ I ₂≈ 0, will make I _J2And I _C2All be approximately zero, reach the purpose of getting rid of stray current.

Fig. 3 is a negative and positive polar region current drainage simultaneously equivalent-circuit diagram.R among the figure _IpCurrent drainage ground connector resistance for the influent stream point A place (negative electrode) that sets up according to the present invention; K _IpBe negative electrode stream discharging system switch.K switch _Ip, K _pAfter closing, following relational expression will be arranged:

${\mathrm{I\; ＇}}_{\mathrm{13}}=\frac{E}{R_N{\mathrm{+\; R＇}}_1{\mathrm{+\; R＇}}_c}\mathrm{(8)}$

$V_{\mathrm{13}}=\frac{{\mathrm{ER＇}}_1}{R_N{\mathrm{+\; R＇}}_1{\mathrm{+\; R＇}}_C}\mathrm{(9)}$

${\mathrm{<figure-callout\; id="13"\; label="I"\; filenames="871029936\_DRIMG3.png"\; state="\{\{state\}\}">I</figure-callout>}}_{\mathrm{13}}=\frac{E}{R_N{\mathrm{+\; R}}_1{\mathrm{+\; R}}_c+\frac{R_N{\mathrm{·\; R}}_1}{R_{\mathrm{I\; P}}}}\mathrm{(10)}$

$V_{\mathrm{c3}}=\frac{{\mathrm{ER\; ＇}}_c}{R_N{\mathrm{+R＇}}_1{\mathrm{+\; R\; ＇}}_c}\mathrm{(11)}$

$I_{\mathrm{c3}}=\frac{E}{R_N{\mathrm{+\; R}}_1{\mathrm{+\; R}}_C+\frac{R_N{\mathrm{·\; R}}_c}{R_p}}\mathrm{(12)}$

In the formula,

${\mathrm{R\; ＇}}_1=\frac{{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_1{\mathrm{·<figure-callout\; id="1"\; label="R\; jp\; R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R\; </figure-callout>}}_{\mathrm{jp}}}{R_{}}$

${\mathrm{R＇}}_C=\frac{R_C{\mathrm{·\; R}}_p}{R_c{\mathrm{+\; R}}_p}$

I ' _J3After the current drainage simultaneously of-negative and positive polar region, enter the stray current of pipeline, A;

R _JpThe row resistor of-influent stream point comprises the forward resistance of diode, Ω;

Inferior numeral " 3 ", the parameter of expression steel pipe negative and positive polar region current drainage simultaneously.

The mark of the same formula of other alphabetical meanings (1)～(7), formula (8)～(12) are exactly negative and positive polar region current drainage simultaneously principle formula.

The establishment condition of formula (10)～(12) is the insulation layer resistance R of steel pipe turnover flow point _j, R _cApproximately equal, current drainage ground connector stake resistance R _Jp, R _pAlso approximately equal.

Formula (8)～(12) and formula (1)～(7) are corresponding relatively can to draw as drawing a conclusion:

1. according to the present invention, current drainage simultaneously can make the anodic polarization of influent stream point in the negative and positive polar region, use the flow point cathodic polarization, strengthen these polar methods and be increasing the insulation resistance of turnover flow point, making the negative and positive polar region reach the spy, to add intensity level anticorrosion, and the strays that reduces electric iron leaks.Simultaneously, increase the stake resistance of electric iron, the position of reasonable Arrangement DC substation, and to reduce the stake resistance that passes in and out the flow point drain means.

2. in order to overcome the negative potential of crossing of influent stream point, only can adopt method, but must be noted that the anodic polarization that causes to other positions of pipeline in the current drainage of influent stream point, take corresponding measure to be overcome.

3. current drainage can only reduce the harm of strays to the steel pipe positive column indirectly, (can not make I but can not obtain electro-chemical protection _C3Equal zero, less than zero), can alleviate the overprotection degree in cathodic area.

4. negative and positive polar region current drainage simultaneously, the drain means of turnover flow point and the path that steel pipe itself has constituted a strays have increased the stray current of pipeline conduction, but have reduced cathodic polarization and the anodic polarization of strays to the turnover flow point.This is the essence of the simultaneously indirect current drainage in negative and positive polar region.

Fig. 4 is the wiring diagram that utilizes four supplementary anodes (promptly getting n=4) and waveform adaptive controller to carry out galvanic protection.The metal structures are example with pipeline G.Illustrate four supplementary anode t ₁～t ₄With the distance of pipeline G, following relation is arranged:

400～500m≥h ₁＞h ₂＞h ₃＞h ₄，

The with dashed lines frame goes out partly to be the schematic diagram of waveform adaptive controller J among the figure.Waveform adaptive controller shown in this figure has 4 branch roads (promptly getting n=4), and every branch road has a variohm (R ₁, R ₂, R ₃, R ₄) electric current (I of each variohm of flowing through ₁, I ₂, I ₃, I ₄) with the reometer (A that is in series with it ₁, A ₂, A ₃, A ₄) measure, the output point of reometer is waveform adaptive controller output point (Z ₁, Z ₂, Z ₃, Z ₄), also promptly organize t with supplementary anode ground connection ₁, t ₂, t ₃, t ₄Tie point, the anode that the other end of four branch roads is formed 1 y and anti-corrosion meter F joins, variohm R ₁～R ₄Specification be generally 0～10 Ω, about 9000W.Reometer can be with positive and negative galvanic current Table A _n, range is generally ± 50A, ± 30A, ± 10A, ± four class of 5A.The monitoring voltage table adopts the positive negative value D.C. voltmeter of high internal resistance, and internal resistance is greater than 100K Ω/V, and its range is ± 10V, ± 5V, and ± 3V, four class of ± 2V also can adopt a voltmeter, add a fourth gear time wave band transfer lever.O is the confluence among the figure, and I is the anti-corrosion meter outward current.

Accompanying drawing 5 is pipe ground polarized potential E-guard space 1 graphic representations.Among the figure 1., 2., 3., 4. four curves are respectively to use supplementary anode t separately ₁～t ₄Send the graphic representation of the polarized potential E-guard space 1 of electric protection gained, the dcbaOEFGH curve is to utilize above-mentioned four supplementary anodes to send total protection graphic representation of electric protection gained simultaneously.This figure guard space 1 place current potential is the spontaneous potential of pipeline, is not zero potential.Total protection curve is to be formed by stacking by four single polarization curves.Then oa, ab, bc, cd section there are following relational expression:

$E_a\mathrm{=\; C}{}_a\mathrm{V\; (}\frac{G_1}{R_H{\mathrm{+<figure-callout\; id="1"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_1}+\frac{G_2}{R_H{\mathrm{+\; <figure-callout\; id="2"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_2}+\frac{G_3}{R_H{\mathrm{+<figure-callout\; id="3"\; label="R"\; filenames="871029936\_DRIMG1.png,871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_3}+\frac{G_4}{R_H{\mathrm{+\; R}}_4}\mathrm{)\; (13)}$

$E_b\mathrm{=\; C}{}_b\mathrm{V\; (}\frac{G_1}{R_H{\mathrm{+\; <figure-callout\; id="1"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_1}+\frac{G_2}{R_H{\mathrm{+\; <figure-callout\; id="2"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_2}+\frac{G_2}{R_H{\mathrm{+R}}_2}\mathrm{)\; (14)}$

$E_c\mathrm{=\; C}{}_c\mathrm{V\; (}\frac{G_1}{R_H{\mathrm{+\; <figure-callout\; id="1"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_1}+\frac{G_2}{R_H{\mathrm{+\; R}}_2}\mathrm{)\; (15)}$

$E_d\mathrm{=C}{}_d\mathrm{V\; (}\frac{G_1}{R_H{\mathrm{+\; R}}_1}\mathrm{)\; (16)}$

In the formula

E _a～E _d-be respectively total each section of protection curve above earth potential, V;

C _a～C _d-be respectively total protection curve correspondent section apart from impedance, Ω;

Equal for the endless pipeline

$\frac{\sqrt{R_{O}r}}{{\mathrm{2C}}^{\mathrm{a\; 1}}}$

Equal for finite length pipe

$\frac{\sqrt{R_{O}r}}{\mathrm{2\; S\; h\; (\; a\; l\; )}}$

The l-guard space, m;

The Sh-sinh;

R-unit's long pipeline longitudinal electrical resistance, Ω/m;

R-unit's long pipeline insulation layer resistance, Ω/m;

The a-reduction coefficient, 1/f equals

$\frac{\sqrt{R}}{r}$

G ₁～G ₄-be respectively t ₁～t ₄Supplementary anode is called for short the anode deviation ratio apart from the deviation ratio of pipeline distance to protection potential; And 0＜G is arranged ₁≤ 1, when supplementary anode during apart from pipeline distance h=400～500m, G ₁=1; Subscript i is a natural number; H is more little, G _jMore little; G _i=f(h),

V-anti-corrosion meter F output voltage, V;

R ₁～R ₄The variable resistor in-each loop, Ω;

R _H-be supplementary anode stake resistance R _tWith wire resistance R _dSum, Ω;

To above-mentioned four formula (13)～(16) partial differential, can obtain the scattered electricity area anti-corrosion meter and send electric protection waveform adaption formula:

(following formula is when i＞3, and only second (CbVG1dR1)/((RH+R1) 2) do not exist)

(following formula when i＞2, second (C only _cVG ₁DR ₁)/((R _H+ R ₁) ²) do not exist)

(following formula when i＞1, second (C only _dVG ₁DR ₁)/((R _H+ R ₁) ²) do not exist)

In the formula

α-partial differential symbol;

The d-differential sign;

The i-subscript is natural number;

R _i-be that any one adjusts resistance, Ω;

A, m, p, Q are respectively:

$\mathrm{=\; <figure-callout\; id="1"\; label="n\; VG"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">n\; </figure-callout>}\frac{{\mathrm{VG}}_{}}{}\frac{{}_1{\mathrm{dR}}_1}{{\mathrm{(R}}_H{\mathrm{+R}}_1\mathrm{)\; -\; (}\frac{G_1}{R_H{\mathrm{+\; <figure-callout\; id="1"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_1}+\frac{G_2}{R_H{\mathrm{+\; <figure-callout\; id="2"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_2}+\frac{G_3}{R_H{\mathrm{+\; <figure-callout\; id="3"\; label="R"\; filenames="871029936\_DRIMG1.png,871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_3}+\frac{G_4}{R_H{\mathrm{+\; R}}_4})}$

$\mathrm{m\; =}\frac{G_1}{R_H{\mathrm{+\; <figure-callout\; id="1"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_1}+\frac{G_2}{R_H{\mathrm{+<figure-callout\; id="2"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_2}+\frac{G_3}{R_H{\mathrm{+\; <figure-callout\; id="3"\; label="R"\; filenames="871029936\_DRIMG1.png,871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_3}$

$\mathrm{p\; =}\frac{G_1}{R_H{\mathrm{+\; <figure-callout\; id="1"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_1}+\frac{G_2}{R_H{\mathrm{+\; <figure-callout\; id="2"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_2}$

$\mathrm{Q\; =}\frac{G_1}{R_H{\mathrm{+\; <figure-callout\; id="1"\; label="R"\; filenames="871029936\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}}_1}$

The mark of the same formula of other alphabetical implications (13)～(16).

Can draw to draw a conclusion by formula (13)～(20):

1. the oa section of always protecting curve is not because of variohm R _iChange and change, be called non-adjustable line segment.Other each sections are called adjustable line segment.Oa fixes on other cathode protecting parameters one regularly really, depends primarily in each protection loop supplementary anode apart from the distance h of pipeline _n

2. adjust the variohm R of anode power transmission system far away ₁, the pipe-to-soil potential rangeability from the farthest, confluence is bigger with making, and near more rangeability is more little; Adjust the variohm R of nearly anode system ₄, potential variation amplitude the most nearby is bigger with making, and rangeability far away more is more little.

Adjust middle distance anode system variohm R ₃, R ₂, a band pipe-to-soil potential rangeability is bigger in the middle of will making, and the two ends rangeability is little, variohm R _nChange each section potential curve amplitude that causes total polarization curve and change, the protection length of each section curve is also changed.

3. variohm R _i～R ₄, when adjusting any one, all will cause the E of total protection curve _b, E _c, E _dThe section amplitude changes, and this change and non-parallel moving up and down, in same section curve by the vary within wide limits of confluence some.

4. variohm R ₁～R ₄When adjusting simultaneously, the oa section amplitude of total polarization curve is constant.The result who adjusts and each resistance adjust one by one that afterwards the synthetic result is the same.As shown in Figure 6, work as R ₁≈ R ₂≈ R ₃During ≈ ∞, always protect the guard space of curve the shortest, always protect the oaa ' in curve such as the accompanying drawing 6.Work as R ₂≈ R ₃≈ R ₄During ≈ ∞, guard space is the longest, as the od ' in the accompanying drawing 6.

Adjust R one by one ₁～R ₄Make total protection curve can only two fan-shaped plans that ray surrounded of oa ', od ' in the accompanying drawings in.This face is referred to as the waveform adaptive surface.If will strengthen it, can only increase pipeline distance supplementary anode distance h farthest ₁With the distance h that reduces nearest supplementary anode ₄Total protection curve is adjusted as shown in Figure 6 arbitrarily.

5. if variohm R ₁～R ₄After adjusting, all fixed, always protected each section of curve E _a～E _dAll will be with confluence current potential E _AlwaysMove by a certain percentage up and down.Like this as long as suitable variohm R _i, just can make the total galvanic protection curve of anti-corrosion meter obtain changing, and make it to be adapted to the balancing waveform that stray current is invaded the metal structures.This process abbreviates waveform as and adapts to.Invade the total protection curve of metal structures balancing waveform being adapted to strays fully, be called waveform and adapt to line.Utilize the waveform adaptive technique; not only make irreversible anti-corrosion meter that the strays potential drop greater than given current potential is arrived the protection potential interval; reach control one point protection purpose completely; but also reversible anti-corrosion meter is all submitted all fronts strays current potential of overreach protection potential region (especially cross negative potential) in scattered electricity area protection potential interval, reach galvanic protection completely-not only protected steel pipe but also make under the preservative coat undermined.Thereby make metal structures prolongs lifes such as underground steel pipe, cable more than 2 times, ensure safety in production.Huge economic benefit and social benefit are arranged.

Claims (5)

1, a kind of current drainage ground connector stray current elimination technique at electric railway area underground metal pipeline is characterized in that being:

1) the negative and positive polar region is carried out the spy simultaneously and add the processing of intensity level anti-corrosion insulation, its insulation resistance Rj and Rc approximately equal simultaneously;

2) also beat the current drainage ground connector in the cathodic area, its stake resistance Rjp and anode current drainage ground connector stake resistance Rp approximately equal;

3) electric locomotive the is powered DC substation of usefulness is arranged on position near the railway two ends, two Z of electric substation ₁, Z ₂Electric locomotive D flows through ₁, D ₂Load current I ₁And I ₂Direction is opposite, the absolute value approximately equal.

2, a kind of underground metal structures safety guard of being made up of anti-corrosion meter F and monitoring voltage table in strays area is characterized in that:

1) beats n group supplementary anode ground connector t ₁, t ₂, t _nThe distance of they and protected structures is respectively h ₁, h ₂..., h _n, and satisfy relation: 400～500m 〉=h ₁＞h ₂＞...＞h _n

2) output cathode with said anti-corrosion meter F is connected on the input terminus y of a waveform adaptive controller J, with the output terminal Z of this waveform adaptive controller J ₁, Z ₂..., Z _nRespectively with described supplementary anode t ₁, t ₁... t _nBe connected.

3) described waveform adaptive controller J is made up of n bar branch road, and every branch road has a variohm R respectively ₁, R ₂..., R _n, the galvanic current Table A that is in series with it ₁, A ₂..., A _n, its output terminal is the output terminal Z of waveform adaptive controller J ₁, Z ₂... Z _n, the input terminus of n bar branch road is become one, forms the input terminus y of entire controller.

3, according to the underground metal structures safety guard of claim 3, it is characterized in that described variohm R ₁, R ₂..., R _nSpecification be 0～10 Ω, about 9000W.

4, according to the underground metal structures safety guard of claim 3, it is characterized in that described galvanic current Table A ₁, A ₂..., A _nRange be ± 50A, ± 30A, ± 10A, ± four class of 5A.

5, a kind of adjustment method of the underground metal structures safety guard of being made up of anti-corrosion meter F, monitoring instrument and supplementary anode ground connector, waveform adaptive controller J in strays area is characterized in that:

1) adjusts variohm R one by one ₁, R ₂... R _n, note observing the shown protection potential curve of corresponding monitoring voltage table, if this curve drops in this scattered electricity area protection potential interval, then debugging finishes;

2) curve exceeds this scattered electricity area protection potential interval as shown, then changes the distance of corresponding supplementary anode group and structures, adjusts this variohm again, in the shown curve of monitoring voltage table drops on this scattered electricity area protection potential interval.

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