CN105608269A - Estimation method of beam length of 500V power transmission line tower pole grounding body - Google Patents

Abstract

The invention discloses an estimation method of the beam length of a 500V power transmission line tower pole grounding body. The estimation method comprises the following steps: establishing a tower pole grounding body model; according to the model, calculating the impulse grounding resistance of the tower pole grounding body model; carrying out fitting calculation on the formula of the impulse grounding resistance of the tower pole grounding body; according to the formula of the impulse grounding resistance, fitting the effective length formula of tower pole grounding body ray; and according to practical soil electrical resistivity, obtaining the effective length of the tower pole grounding body ray, wherein the grounding body model comprises four steel bodies and the tower pole grounding body ray arranged on the steel bodies, a square of which the side length is 18m is formed by the four steel bodies, and the adjacent tower pole grounding body rays are not on the same endpoint. The estimation method of the beam length of the 500V power transmission line tower pole grounding body provides a theoretical basis for the design and the transformation of a power transmission line tower pole grounding device, and is favorable for obtaining an excellent grounding body.

Description

A kind of 500kV electric power line pole tower grounding body ray length evaluation method

Technical field

The present invention relates to electric power transportation art, more specifically, relate to a kind of 500kV electric power line pole tower grounding body and penetrateLine length evaluation method.

Background technology

In recent years, the many areas of China recur because of the large area short circuit power cut that causes of thunderbolt, its reason be mostly byCause in the impulse earthed resistance of electric power line pole tower grounding body is too high. Electric power line pole tower grounding body is protection power systemNear the important measures of personal security safe and reliable operation, protection, tower grounding device diffusing is bad causes that impulse resistance is excessiveIt is the main cause that causes transmission line lightning stroke tripping operation.

Recent domestic scholar has carried out a large amount of research for the impulse earthed resistance of earthing or grounding means, proposes various fallingResistance measure, finds to extend the horizontal grounding utmost point and increase earthing pole quantity and can reduce impulse earthed resistance, but grounding body reaches oneAfter fixed length, continue extend grounding body its fall resistance effect of optimization can decline, also there will be same grounding body in difference simultaneouslyRegional result of use difference, cause sometimes earthing material waste, and grounding body does not reach technical requirement sometimesEffect.

Visible, how better grounding body is provided, be those skilled in the art's problem demanding prompt solutions.

Summary of the invention

The object of this invention is to provide a kind of 500kV electric power line pole tower grounding body ray length evaluation method, is transmission of electricityThe Design & reform of overhead line structures earthing or grounding means provides theoretical foundation, contributes to obtain better grounding body.

In order to solve the problems of the technologies described above, the invention provides following technical scheme:

A kind of 500kV electric power line pole tower grounding body ray length evaluation method provided by the invention, the length of described rayDegree computational methods comprise:

Set up tower grounding body Model;

Calculate the impulse earthed resistance of tower grounding body Model according to model;

The formula of the impulse earthed resistance of the Fitting Calculation tower grounding body;

According to the formula of described impulse earthed resistance, the effective length formula of matching tower grounding body ray;

Obtain the effective length of tower grounding body ray according to actual soil resistivity;

Wherein: described grounding body model comprises four steel bodies and be arranged on the tower grounding body ray on described steel body,The square that described four steel bodies composition length of side is 18m, adjacent described tower grounding body ray is not total to end points.

Preferably, in above-mentioned 500kV electric power line pole tower grounding body ray length evaluation method, describedly calculate according to modelThe impulse earthed resistance of tower grounding body Model, matching obtains the formula of the impulse earthed resistance of tower grounding body

R＝1.1+0.009ρ+(0.02ρ-0.97)·e^bl(l≥0)

Wherein: R is impulse earthed resistance, ρ is soil resistivity, and e is natural constant, $b=-0.127e^{-4.63\×{10}^{-3}\·\mathrm{\ρ}}-0.042e^{2.38\×{10}^{-5}\·\mathrm{\ρ}}.$

Preferably, in above-mentioned 500kV electric power line pole tower grounding body ray length evaluation method, described according to described impactThe formula of earth resistance, the effective length formula of matching tower grounding body ray, specifically comprises:

Impulse earthed resistance, to the differentiate of described grounding body length, is supposed

Obtain α=5 °, obtain the effective length l of electric power line pole tower junctor ray according to α matching_e， $l_e=73.79e^{2.212\×{10}^{-5}\mathrm{\ρ}}-82.64e^{-1.341\×{10}^{-3}\mathrm{\ρ}}.$

Wherein: α meets the tangent line of this formula requirement point and the angle of horizontal direction on R curve.

Preferably, in above-mentioned 500kV electric power line pole tower grounding body ray length evaluation method, when ρ is less than or equal to 100When Ω m, l_e≈0m。

Preferably, in above-mentioned 500kV electric power line pole tower grounding body ray length evaluation method, described electric line shaft tower connectsThe effective length l of body ray_e, in the time that ρ is greater than 100 Ω m, the effective length l of electric power line pole tower junctor ray_e， $l_e=73.79e^{2.212\×{10}^{-5}\mathrm{\ρ}}-82.64e^{-1.341\×{10}^{-3}\mathrm{\ρ}}.$

Preferably, in above-mentioned 500kV electric power line pole tower grounding body ray length evaluation method, described method also comprises:According to the effective length formula of tower grounding body ray, obtain the effective length of tower grounding body ray according to soil resistivity;

According to the effective length of described tower grounding body ray, calculate impulse earthed resistance R;

Relatively designing requirement impulse earthed resistance R₀With the size of R,

Work as R₀When < R, grounding body ray length l_eDo not meet design requirement; Otherwise meet design requirement.

Preferably, in above-mentioned 500kV electric power line pole tower grounding body ray length evaluation method, described steel body be band steel orRound steel.

500kV electric power line pole tower grounding body ray length evaluation method provided by the invention, provide a kind of forThe good grounding body model of 500kV electric power line pole tower provides a kind of method of estimating grounding body ray length simultaneously, helpsIn effectively utilizing the effective diffusing length of grounding body, avoid unnecessary waste of material simultaneously. Can at utmost utilize shaft tower to connectThe steel of ground device, and for the Design & reform of electric power line pole tower earthing or grounding means provides theoretical foundation, contribute to provide excellentGood electric power line pole tower earthing or grounding means.

Brief description of the drawings

In order to be illustrated more clearly in the technical scheme in the embodiment of the present invention, required making in describing embodiment belowWith accompanying drawing be briefly described, apparently, for those of ordinary skills, do not paying creative workUnder the prerequisite of property, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is the grounding body model schematic diagram that the embodiment of the present invention provides;

Fig. 2 is impulse earthed resistance and the tower grounding body ray length relationship change figure that the embodiment of the present invention provides;

Fig. 3 is effective length and the soil resistivity graph of a relation of the tower grounding body ray that provides of the embodiment of the present invention.

Detailed description of the invention

A kind of 500kV electric power line pole tower grounding body ray length evaluation method that the embodiment of the present invention provides is transmission of electricityThe Design & reform of overhead line structures earthing or grounding means provides theoretical foundation, contributes to obtain better grounding body.

In order to make those skilled in the art person understand better the technical scheme in the embodiment of the present invention, and make the present invention realExecute routine above-mentioned purpose, feature and advantage can become apparent more, below in conjunction with accompanying drawing to the technology in the embodiment of the present inventionScheme is described in further detail.

A kind of 500kV electric power line pole tower grounding body ray length evaluation method that the embodiment of the present invention provides, mainly bagDraw together:

Set up tower grounding body Model.

Described grounding body model comprises four steel bodies and is arranged on the tower grounding body ray on described steel body, described fourThe square that the root steel body composition length of side is 18m, adjacent described tower grounding body ray is not total to end points, forms windmill shape and penetratesLine, with reference to accompanying drawing 1, the figure shows structure and the shape of the grounding body model that the embodiment of the present invention provides. Grounding body model canAdopt band steel or round steel to be made. Preferably, the cross-sectional width of band steel is greater than 40 millimeters, and thickness is more than or equal to 5 millimeters;Or in the time adopting round steel, round steel diameter is greater than 10 millimeters.

Calculate the impulse earthed resistance of tower grounding body Model according to model.

For obtaining the impulse earthed resistance of tower grounding body Model, to 500kV electric power line pole tower grounding body ray length,Relation between soil resistivity and impulse earthed resistance three is analyzed, and a kind of analysis side is provided in the embodiment of the present inventionMethod, sets up CDEGS shaft tower simulation analysis model, and when in model, grounding body adopts round steel, round steel diameter is greater than 10 millimeters. At modelIn by changing the length of soil resistivity and grounding body ray length, calculate respectively the impulse earthed resistance of shaft tower.

As, in CDEGS software, changing respectively ray length is 0m, 3m, 6m, 12m, 18m, 32m, 46m, 57m, 79m,And soil resistivity be set as respectively 100 Ω m, 200 Ω m, 300 Ω m, 400 Ω m, 500 Ω m, 800 Ω m,1000 Ω m, 1500 Ω m, 2000 Ω m, 2500 Ω m, 3000 Ω m, obtain impulse grounding electricity by simulation calculationResistance distributes as shown in Figure 2.

With reference to accompanying drawing 2, which kind of soil resistivity is analysis no matter can obtain under, and the impulse resistance of earthing or grounding means is all along with rayThe increase of length and reducing, and there is saturated trend after reaching certain length. Therefore,, in the time that ray reaches certain length, continueThe long shot line length that renews does not have resistance reducing effect substantially, and we are defined as this length the effective length of tower grounding device.

To curve in accompanying drawing 2 carry out matching obtain the impulse earthed resistance of 500kV tower grounding body and soil resistivity andThe relational expression of ray length is:

The formula of the impulse earthed resistance of the Fitting Calculation tower grounding body: R=1.1+0.009 ρ+(0.02 ρ-0.97) e^bl(l >=0), itsIn: R is impulse earthed resistance, and ρ is soil resistivity, and e is natural constant, $b=-0.127e^{-4.63\&times;{10}^{-3}\&CenterDot;\mathrm{\&rho;}}-0.042e^{2.38\&times;{10}^{-5}\&CenterDot;\mathrm{\&rho;}}.$

According to the formula of described impulse earthed resistance, the effective length formula of matching tower grounding body ray.

Adopt the document " Effective of IEEETRANSACTIONSONPOWERDELIVERY the 2nd phase in 2005LengthofCounterpoiseWireUnderLightningCurrent " method that provides: will meet impulse groundingEarthing pole length when resistance is less than a certain setting to the derivative of grounding body length is defined as the effective length of earthing pole, that is:In formula, α meets the tangent line of this formula requirement point and the angle of horizontal direction on curve. In the time of α=5 °, continueThe long shot line length that renews, the variation of impulse earthed resistance is very little, can think that now ray reaches its effective length.

With reference to accompanying drawing 3, matching obtains the effective length l of electric line shaft tower junctor ray_e， $l_e=73.79e^{2.212\&times;{10}^{-5}\mathrm{\&rho;}}-82.64e^{-1.341\&times;{10}^{-3}\mathrm{\&rho;}}.$

In the time that soil resistivity is 100 Ω m, the effective length l of tower grounding body ray_eBe only 1.89m, when ρ=When 100 Ω m, l_e=1.89m, so can select, in the time that soil resistivity is less than 100 Ω m, has tower grounding body rayEffective length l_eCan be similar to and think 0m, in the time of the Ω m of ρ≤100, l_e≈0m。

Obtain the effective length of tower grounding body ray according to actual soil resistivity.

By the above-mentioned formula of soil resistivity substitution obtaining, obtain shaft tower grounding body ray under this soil resistivity effectivelyLength l_e。

So, obtaining after the effective length of tower grounding body ray, can also having according to this tower grounding body rayEffect length judges whether this effective length meets design needs. By the effective length of the tower grounding body ray calculatingTreat into $R=1.1+0.009\mathrm{\&rho;}+(0.02\mathrm{\&rho;}-0.97)\&CenterDot;e^{{\mathrm{bl}}_e},(l_e\&GreaterEqual;0),$ Ask for R value, by itself and designing requirement or requirements R₀EnterRow is (designing requirement or requirements are R0) relatively. Work as R₀When < R, grounding body ray length l_eDo not meet design requirement; Otherwise meetDesigning requirement.

As R0 > R, grounding body ray length l_eWhile meeting design requirement, the grounding body ray length l that this shaft tower adopts gets in conservative designEffective length l_e; Can calculate by following formula from saving material l: $l=\frac{1}{b}\left(ln\right(R-1.1-0.009\mathrm{\&rho;})-ln(0.02\mathrm{\&rho;}-0.97\left)\right).$

In the time of R0 < R, the ray length that now extends shaft tower grounding body cannot effectively reduce impulse earthed resistance, thereforeL gets effective length l_e, now adopt by increasing other measures such as amount of radiation and fall resistance.

500kV electric power line pole tower grounding body ray length evaluation method provided by the invention, provide a kind of forThe good grounding body model of 500kV electric power line pole tower provides a kind of method of estimating grounding body ray length simultaneously, helpsIn effectively utilizing the effective diffusing length of grounding body, avoid unnecessary waste of material simultaneously. Can at utmost utilize shaft tower to connectThe steel of ground device, and for the Design & reform of electric power line pole tower earthing or grounding means provides theoretical foundation, contribute to provide excellentGood electric power line pole tower earthing or grounding means.

Each embodiment in this description all adopts the mode of going forward one by one to describe, identical similar portion between each embodimentPoint mutually referring to, what each embodiment stressed is and the difference of other embodiment.

Above-described embodiment of the present invention, does not form limiting the scope of the present invention. Any in the present inventionSpirit and principle within do amendment, be equal to and replace and improvement etc., within all should being included in protection scope of the present invention.

Claims (7)

1. a 500kV electric power line pole tower grounding body ray length evaluation method, is characterized in that, the length gauge of described rayCalculation method comprises:

Set up tower grounding body Model;

Calculate the impulse earthed resistance of tower grounding body Model according to model;

The formula of the impulse earthed resistance of the Fitting Calculation tower grounding body;

According to the formula of described impulse earthed resistance, the effective length formula of matching tower grounding body ray;

Obtain the effective length of tower grounding body ray according to actual soil resistivity;

Wherein: described grounding body model comprises four steel bodies and be arranged on the tower grounding body ray on described steel body, described inFour squares that the steel body composition length of side is 18m, adjacent described tower grounding body ray is not total to end points.

2. 500kV electric power line pole tower grounding body ray length evaluation method according to claim 1, is characterized in that,The described impulse earthed resistance that calculates tower grounding body Model according to model, matching obtains the impulse earthed resistance of tower grounding bodyFormula

R＝1.1+0.009ρ+(0.02ρ-0.97)·e^bl(l≥0)

Wherein: R is impulse earthed resistance, ρ is soil resistivity, and l is tower grounding body ray length, and e is natural constant, $b=-0.127e^{-4.63\&times;{10}^{-3}\&CenterDot;\mathrm{\&rho;}}-0.042e^{2.38\&times;{10}^{-5}\&CenterDot;\mathrm{\&rho;}}.$

3. 500kV electric power line pole tower grounding body ray length evaluation method according to claim 2, is characterized in that,Described according to the formula of described impulse earthed resistance, the effective length formula of matching tower grounding body ray, specifically comprises:

Impulse earthed resistance, to the differentiate of described grounding body length, is supposed

Obtain α=5 °, obtain the effective length l of electric power line pole tower junctor ray according to α matching_e， $l_e=73.79e^{2.212\&times;{10}^{-5}\mathrm{\&rho;}}-82.64e^{-1.341\&times;{10}^{-3}\mathrm{\&rho;}};$

Wherein: α meets the tangent line of this formula requirement point and the angle of horizontal direction on R curve.

4. 500kV electric power line pole tower grounding body ray length evaluation method according to claim 3, is characterized in that,In the time that ρ is less than or equal to 100 Ω m, l_e≈0m。

5. 500kV electric power line pole tower grounding body ray length evaluation method according to claim 3, is characterized in that,The effective length l of described electric line shaft tower junctor ray_e, in the time that ρ is greater than 100 Ω m, the having of electric power line pole tower junctor rayEffect length l_e， $l_e=73.79e^{2.212\&times;{10}^{-5}\mathrm{\&rho;}}-82.64e^{-1.341\&times;{10}^{-3}\mathrm{\&rho;}}.$

6. 500kV electric power line pole tower grounding body ray length evaluation method according to claim 5, is characterized in that,Described method also comprises: according to the effective length formula of tower grounding body ray, obtain tower grounding body according to soil resistivityThe effective length of ray;

According to the effective length of described tower grounding body ray, calculate impulse earthed resistance R;

Relatively designing requirement impulse earthed resistance R₀With the size of R,

Work as R₀When < R, grounding body ray length l_eDo not meet design requirement; Otherwise meet design requirement.

7. 500kV electric power line pole tower grounding body ray length evaluation method according to claim 1, is characterized in that,Described steel body is band steel or round steel.