CN106096225A - The power station of a kind of karst area geomorphic feature or the preparation method of grounding net of transformer substation resistance value - Google Patents

Abstract

The power station of a kind of karst area geomorphic feature or the preparation method of grounding net of transformer substation resistance value, comprise the following steps: step one, determines ground connection soil resistivity and test point；Step 2, the resistance value of calculating main grounding grid；Step 3, calculating reduce the subsidiary grounding grids resistance value of soil resistivity；Step 4, the power station calculating karst area geomorphic feature or the resistance value of grounding net of transformer substation.The present invention provides power station or the preparation method of grounding net of transformer substation resistance value of a kind of karst area geomorphic feature, solves that the grounded screen soil resistivity of karst area geomorphic feature is uneven and high two technical barriers of soil resistivity.

Description

The power station of a kind of karst area geomorphic feature or obtaining of grounding net of transformer substation resistance value The method of obtaining

Technical field

The present invention relates to grounding technology field, the power station of a kind of karst area geomorphic feature or substation grounding The preparation method of net resistance value.

Background technology

Power station or grounding net of transformer substation are the important component parts in power system practice of construction engineering, with the length of transformer station Phase normal safe runs closely bound up.Karst " stony desertification ", karst and mountain valley landforms, soil is few, water storage capacity Low, such Geological And Geomorphological Features, the high soil resistivity of its soil resistivity is high, and the geological condition of diverse location differs very Greatly, the good and bad direct relation of design Grounding performance arrives at a station the personal safety of interior staff and the peace of various electrical equipment Entirely, the therefore grounded screen for the treatment of in accordance with local conditions sexual valence reasonable in design ratio, reasonable computation grounded screen electric resistance has the actual meaning of stronger engineering Adopted and preferable economic worth.

The empirical equation that ground grid design is dependent on design manual (includes impedance ground, step voltage and contact voltage Deng) complete in conjunction with the experience of designer self.These empirical equations are the summaries of work about electric power person's many years of experience, have relatively High practical value, is widely used in ground grid design.But traditional empirical equation is at design complex condition (Ru Kasi Specially district) grounded screen time there is obvious defect: the empirical equation on design manual does not accounts for the inhomogeneities of soil, Ka Si The soil of special Geological And Geomorphological Features is the most uneven, and traditional empirical equation is considered as uniform soil soil, thus results in very Big calculating error, this invention can significantly reduce this error.This invention uses " exogenous ", " compound simultaneously Building " and " deeply visiting formula " three kinds of methods to the soil resistivity solving karst area geomorphic feature this defect high and more smart The resistance of true calculating grounded screen, makes grounded screen parameter reach design and construction reference.

Summary of the invention

The technical problem to be solved is to provide the power station of a kind of karst area geomorphic feature or transformer station connects The preparation method of earth mat resistance value, solve karst area geomorphic feature grounded screen soil resistivity is uneven and electric resistance of soil High two technical barriers of rate.

For solving above-mentioned technical problem, the technical solution adopted in the present invention is: a kind of karst area geomorphic feature Power station or the preparation method of grounding net of transformer substation resistance value, it is characterised in that comprise the following steps:

Step one, determine ground connection soil resistivity and test point；

Step 2, the resistance value of calculating main grounding grid；

Step 3, calculating reduce the subsidiary grounding grids resistance value of soil resistivity；

Step 4, the power station calculating karst area geomorphic feature or the resistance value of grounding net of transformer substation.

Further, described determine that ground connection soil resistivity and test point method are as follows: choose n test point, grounded screen Draw the soil density soil density more than other position measurement points of grounded screen of place's test point of reaching the standard grade；Then grounded screen soil is calculated Average resistivity ρ_∑, use weighted mean method, ρ_∑=α₁ρ₁+α₂ρ₂+…α_nρ_n, and α₁+α₂+…α_n=1, α₁,α₂…α_nFor correspondence Test point weights, ρ₁,ρ₂,…ρ_nResistivity for corresponding grounded screen soil testing point.

Further, the resistance value method of described calculating main grounding grid is as follows: main grounding grid use level lay grounding body and Vertical ground connection, combines the composition main grounding device of combined type artificial, and main grounding body separates with the grounding body of lightning arrester；Tiling sets and connects Terrain uses Hot-dip zinc-coated flat steel sheet to be welded, and Grounding Grids uses hot galvanized steel pipe to be evenly distributed on the surrounding in grounded screen place And central point, the resistance of level laying grounding body is:

$R_1=\frac{{\mathrm{\ρ}}_{\mathrm{\Σ}}}{2{\mathrm{\πL}}_c}(ln\frac{2L_c}{a^{\′}}+\frac{k_1{L}_c}{\sqrt{A}}-k_2)---\left(1\right)$

The resistance of Grounding Grids is:

$R_2=\frac{{\mathrm{\ρ}}_{\mathrm{\Σ}}}{2{\mathrm{\πn}}_r{L}_r}\[ln\frac{4L_r}{b}-1+\frac{2k_1{L}_r}{\sqrt{A}}{(\sqrt{n_r}-1)}^2\]---\left(2\right)$

Resistance between level laying grounding body welds with Grounding Grids is:

$R_m=\frac{{\mathrm{\ρ}}_{\mathrm{\Σ}}}{{\mathrm{\πL}}_c}(ln\frac{2L_c}{L_r}+\frac{k_1{L}_c}{\sqrt{A}}-k_2+1)---\left(3\right)$

In formula (1)-(3), Lc is grounded screen mesh conductor length, and Lr is the length that grounded screen Grounding Grids every is excellent, a Lay the diameter of grounding body for level, b is the diameter of Grounding Grids,A ＇ is conductor value, and wherein, h is main ground connection The thickness of net, A is the area that main grounding grid covers, and nr is the number of conductors of main grounding grid, and k 1, k2 are regulation coefficient, by following formula Determine

$\left\{\begin{array}{c}{k}_1=-0.04\frac{x}{y}+1.41,h=0\\ k_1=-0.05\frac{x}{y}+1.20,h=\frac{1}{10}\sqrt{A}\\ k_1=-0.05\frac{x}{y}+1.13,h=\frac{1}{6}\sqrt{A}\end{array}\right.---\left(4\right)$

$\left\{\begin{array}{c}{k}_1=-0.04\frac{x}{y}+1.41,h=0\\ k_1=-0.05\frac{x}{y}+1.20,h=\frac{1}{10}\sqrt{A}\\ k_1=-0.05\frac{x}{y}+1.13,h=\frac{1}{6}\sqrt{A}\end{array}\right.---\left(5\right)$

In formula (4), (5), x, y are respectively grounded screen length and width.

Further, described subsidiary grounding grids can use " exogenous ", " compound building " or " deeply visiting formula ".

Further, described " exogenous " uses extension subsidiary grounding grids to be connected with main grounding grid, and extension subsidiary grounding grids is adopted Use high-efficient graphite earthing module；Extension subsidiary grounding grids symmetrical main grounding grid surrounding；High-efficient graphite earthing module quantity meter Calculate ω=Ceiling [(ρ_∑λ/Rk), 1], take its higher limit；It is big that the method is mainly used in station address, and open, and extension assists Grounded screen electric resistance

$R_f=\frac{1}{\mathrm{\ω}}{R}_{\mathrm{\ω}}=\frac{1}{Ceiling\[({\mathrm{\ρ}}_{\mathrm{\Σ}}\mathrm{\λ}/Rk),1\]}{R}_{\mathrm{\ω}}---\left(6\right)$

In formula (6), λ is that ground connection cheats diameter, and numerical value is provided by high-efficient graphite earthing module manufacturer；R is ground grid design Required value；K is regulation coefficient, and span is 0.6-0.9, depends on ρ_∑；R_ωIt it is the resistance of monolithic high-efficient graphite earthing module.

Further, it is characterised in that described " compound building " uses upper and lower two-layer stereo grounding mesh, before place backfills, Under original ground, lay subsidiary grounding grids, press grid organization with zinc-coated flat steel sheet, add vertical grounding electrode in edge zone, connecing Earth mat side employing zinc-coated flat steel sheet is made ground lead and is connected with upper strata main grounding grid.Upper strata main grounding grid uses zinc-coated flat steel sheet to press net Lattice tissue, below the designed elevation that is laid in, between levels, upper strata grounding body and each building ensure safe distance.The party It is little that method is mainly used in site floor space, and is petrographic province, " compound building " subsidiary grounding grids resistance

$R_f=\frac{R_1{R}_2-R_m^2}{R_1+R_2-R_m}---\left(7\right).$

Further, it is characterised in that described " deeply visiting formula " uses the mode beating ion earthing deep-well, outside grounded screen Enclose, choose installation vertical ion ground connection well, in parallel with station district main grounding grid.Electric operation platform and around laying cement gravel simultaneously Stone ground, in order to improve subsurface resistivities, reduces the person and undertakes voltage.For preventing the impact of transfer voltage, lead to the pipe outside station Road all uses insulation.The modes such as doorway, the station employing hat brim type equal pressure zone process that the personnel such as gate are more, improve further and connect The safety on ground, " deeply visiting formula " subsidiary grounding grids resistance

$R_f=\frac{{\mathrm{\ρ}}_{\mathrm{\Σ}}}{2{\mathrm{\πn}}_r{L}_r}\[ln\frac{4L_r}{b}-1+\frac{2k_1{L}_r}{\sqrt{A}}{(\sqrt{n_r}-1)}^2\]---\left(8\right).$

Further, it is characterised in that the power station of described calculating karst area geomorphic feature or the electricity of grounding net of transformer substation Resistance is R_f//R_g。

Compared to existing technology, there is advantages that

1) this invention has taken into full account that the grounded screen address soil resistivity of karst area geomorphic feature is uneven, it is to avoid Traditional empirical equation is considered as uniform soil soil, and causes the error that grounded screen electric resistance calculates.

2) the main grounding grid resistance of karst area geomorphic feature is taked accurately to calculate, and is not traditional empirical estimating.

3) after using effectively reduction high soil resistivity measure, it is achieved that the accurate calculating of subsidiary grounding grids resistance.

Detailed description of the invention

The power station of a kind of karst area geomorphic feature or the preparation method of grounding net of transformer substation resistance value, its feature exists In, comprise the following steps:

Step one, determine ground connection soil resistivity and test point；

Step 2, the resistance value of calculating main grounding grid；

Step 3, calculating reduce the subsidiary grounding grids resistance value of soil resistivity；

Step 4, the power station calculating karst area geomorphic feature or the resistance value of grounding net of transformer substation.

Further, described determine that ground connection soil resistivity and test point method are as follows: choose n test point, grounded screen Draw the soil density soil density more than other position measurement points of grounded screen of place's test point of reaching the standard grade；Then grounded screen soil is calculated Average resistivity ρ_∑, use weighted mean method, ρ_∑=α₁ρ₁+α₂ρ₂+…α_nρ_n, and α₁+α₂+…α_n=1, α₁,α₂…α_nFor correspondence Test point weights, ρ₁,ρ₂,…ρ_nResistivity for corresponding grounded screen soil testing point.

Further, the resistance value method of described calculating main grounding grid is as follows: main grounding grid use level lay grounding body and Vertical ground connection, combines the composition main grounding device of combined type artificial, and main grounding body separates with the grounding body of lightning arrester；Tiling sets and connects Terrain uses Hot-dip zinc-coated flat steel sheet to be welded, and Grounding Grids uses hot galvanized steel pipe to be evenly distributed on the surrounding in grounded screen place And central point, the resistance of level laying grounding body is:

$R_1=\frac{{\mathrm{\ρ}}_{\mathrm{\Σ}}}{2{\mathrm{\πL}}_c}(ln\frac{2L_c}{q^{\′}}+\frac{k_1{L}_c}{\sqrt{A}}-k_2)---\left(1\right)$

The resistance of Grounding Grids is:

$R_2=\frac{{\mathrm{\ρ}}_{\mathrm{\Σ}}}{2{\mathrm{\πn}}_r{L}_r}\[ln\frac{4L_r}{b}-1+\frac{2k_1{L}_r}{\sqrt{A}}{(\sqrt{n_r}-1)}^2\]---\left(2\right)$

Resistance between level laying grounding body welds with Grounding Grids is:

$R_m=\frac{{\mathrm{\ρ}}_{\mathrm{\Σ}}}{{\mathrm{\πL}}_c}(ln\frac{2L_c}{L_r}+\frac{k_1{L}_c}{\sqrt{A}}-k_2+1)---\left(3\right)$

In formula (1)-(3), Lc is grounded screen mesh conductor length, and Lr is the length that grounded screen Grounding Grids every is excellent, a Lay the diameter of grounding body for level, b is the diameter of Grounding Grids,A ＇ is conductor value, and wherein, h is main ground connection The thickness of net, A is the area that main grounding grid covers, and nr is the number of conductors of main grounding grid, and k 1, k2 are regulation coefficient, by following formula Determine

$\left\{\begin{array}{c}{k}_1=-0.04\frac{x}{y}+1.41,h=0\\ k_1=-0.05\frac{x}{y}+1.20,h=\frac{1}{10}\sqrt{A}\\ k_1=-0.05\frac{x}{y}+1.13,h=\frac{1}{6}\sqrt{A}\end{array}\right.---\left(4\right)$

$\left\{\begin{array}{c}{k}_1=-0.04\frac{x}{y}+1.41,h=0\\ k_1=-0.05\frac{x}{y}+1.20,h=\frac{1}{10}\sqrt{A}\\ k_1=-0.05\frac{x}{y}+1.13,h=\frac{1}{6}\sqrt{A}\end{array}\right.---\left(5\right)$

In formula (4), (5), x, y are respectively grounded screen length and width.

Further, described subsidiary grounding grids can use " exogenous ", " compound building " or " deeply visiting formula ".

Further, described " exogenous " uses extension subsidiary grounding grids to be connected with main grounding grid, and extension subsidiary grounding grids is adopted Use high-efficient graphite earthing module；Extension subsidiary grounding grids symmetrical main grounding grid surrounding；High-efficient graphite earthing module quantity meter Calculate ω=Ceiling [(ρ_∑λ/Rk), 1], take its higher limit；It is big that the method is mainly used in station address, and open, and extension assists Grounded screen electric resistance

$R_f=\frac{1}{\mathrm{\ω}}{R}_{\mathrm{\ω}}=\frac{1}{Ceiling\[({\mathrm{\ρ}}_{\mathrm{\Σ}}\mathrm{\λ}/Rk),1\]}{R}_{\mathrm{\ω}}---\left(6\right)$

In formula (6), λ is that ground connection cheats diameter, and numerical value is provided by high-efficient graphite earthing module manufacturer；R is ground grid design Required value；K is regulation coefficient, and span is 0.6-0.9, depends on ρ_∑；R_ωIt it is the resistance of monolithic high-efficient graphite earthing module.

Further, it is characterised in that described " compound building " uses upper and lower two-layer stereo grounding mesh, before place backfills, Under original ground, lay subsidiary grounding grids, press grid organization with zinc-coated flat steel sheet, add vertical grounding electrode in edge zone, connecing Earth mat side employing zinc-coated flat steel sheet is made ground lead and is connected with upper strata main grounding grid.Upper strata main grounding grid uses zinc-coated flat steel sheet to press net Lattice tissue, below the designed elevation that is laid in, between levels, upper strata grounding body and each building ensure safe distance.The party It is little that method is mainly used in site floor space, and is petrographic province, " compound building " subsidiary grounding grids resistance

$R_f=\frac{R_1{R}_2-R_m^2}{R_1+R_2-R_m}---\left(7\right).$

Further, it is characterised in that described " deeply visiting formula " uses the mode beating ion earthing deep-well, outside grounded screen Enclose, choose installation vertical ion ground connection well, in parallel with station district main grounding grid.Electric operation platform and around laying cement gravel simultaneously Stone ground, in order to improve subsurface resistivities, reduces the person and undertakes voltage.For preventing the impact of transfer voltage, lead to the pipe outside station Road all uses insulation.The modes such as doorway, the station employing hat brim type equal pressure zone process that the personnel such as gate are more, improve further and connect The safety on ground, " deeply visiting formula " subsidiary grounding grids resistance

$R_f=\frac{{\mathrm{\ρ}}_{\mathrm{\Σ}}}{2{\mathrm{\πn}}_r{L}_r}\[ln\frac{4L_r}{b}-1+\frac{2k_1{L}_r}{\sqrt{A}}{(\sqrt{n_r}-1)}^2\]---\left(8\right).$

Further, it is characterised in that the power station of described calculating karst area geomorphic feature or the electricity of grounding net of transformer substation Resistance is R_f//R_g。

As a example by certain transformer station of certain karst area geomorphic feature, floor space is more than 6000 square metre, and site is average annual Thunderstorm day, d/A was 49.7, and site environment geological conditions is poor, is mostly the rock cuttings crack of stone of extruding, and has many places small-sized molten Hole, subsoil water difficulty, survey the on-the-spot topsoil resistivity value recorded the same day in 300-500 Europe. rice.Main grounding grid is by level Grounding body uses the Hot-dip zinc-coated flat steel sheet of 60*8 to reticulate horizontal grounding objects by 6 meters of spaced sets, and buried depth 0.8 meter, Grounding Grids is adopted With 100mm, the coating steel pipe of long 20 meters, it is evenly distributed on surrounding and the central point in place.Choose 100 resistivity measurement points, Weighted mean method is used to obtain ρ_∑=α₁ρ₁+α₂ρ₂+…α_nρ_nThe Hot-dip zinc-coated flat steel sheet of=400 Ω .m, 60*8 constitutes netted horizontal grounding Body overall length 10800 meters；Equipment downlead uses the Hot-dip zinc-coated flat steel sheet overall length 2000 meters of 80*8；Grounding Grids overall length 136 meters；Weldering Contact 1116.Condition presses the present invention main grounding body resistance Rg=10.33 Europe, DL/T 621-1997 alternating-current electric device accordingly The requirement of ground connection, power frequency earthing resistance is not more than 0.5 Europe, and therefore main grounding grid is unsatisfactory for design load.

Take " exogenous " auxiliary earth, on the southeast of site, southwest, direction, three, northwest, set up three auxiliary respectively Grounded screen is connected with main grounding grid, and auxiliary earth pole uses third generation high-efficient graphite earthing module, and (manufacturer carries in λ=0.14 For), ρ_∑=400 Europe rice, so K=0.8, R=0.5 Europe, bring ω=Ceiling [(ρ into_∑λ/Rk), 1], 150 pieces can be used to connect Ground module, be assigned to three auxiliary earths extremely in.Then grounded screen all-in resistance is R_f//R_g=0.49 Europe, has reached service requirement.

Another embodiment: the power station of karst area geomorphic feature or grounding net of transformer substation use " compound building " auxiliary to connect Ground, site floor space is little, and be petrographic province, uses upper and lower two-layer stereo grounding mesh, place backfill before, original ground it At lower 0.5 meter, lay subsidiary grounding grids, with the zinc-coated flat steel sheet of 60*8 by 20 meters of * 20 meters of grid organizations, add in edge zone and beat 2.5 meters of long vertical grounding electrodes, use the zinc-coated flat steel sheet of 4 road 80*8 to make ground lead and upper strata main grounding grid in grounded screen side It is connected.Upper strata main grounding grid use the zinc-coated flat steel sheet of 60*8 by 10 meters of * 10 meters of grid organizations, below the designed elevation that is laid in 0.8 Rice, from 10 meters between levels, upper strata grounding body ensures safe distance with each building.Condition is connect by master of the present invention accordingly Bulk resistor Rf=0.45 Europe, ground.Rg=10.33 Europe in embodiment 1, then grounded screen all-in resistance R_f//R_g=0.43 Europe, reaches Service requirement.

The above embodiments are only the preferred technical solution of the present invention, and are not construed as the restriction for the present invention, this The technical scheme that bright protection domain should be recorded with claim, including technical characteristic in the technical scheme that claim is recorded Equivalents is protection domain.Equivalent the most in this range is improved, also within protection scope of the present invention.

Claims (8)

1. the power station of a karst area geomorphic feature or the preparation method of grounding net of transformer substation resistance value, it is characterised in that Comprise the following steps:

Step one, determine ground connection soil resistivity and test point；

Step 2, the resistance value of calculating main grounding grid；

Step 3, calculating reduce the subsidiary grounding grids resistance value of soil resistivity；

Step 4, the power station calculating karst area geomorphic feature or the resistance value of grounding net of transformer substation.

The power station of a kind of karst area geomorphic feature or the acquisition of grounding net of transformer substation resistance value Method, it is characterised in that described determine that ground connection soil resistivity and test point method are as follows: choose n test point, grounded screen Draw the soil density soil density more than other position measurement points of grounded screen of place's test point of reaching the standard grade；Then grounded screen soil is calculated Average resistivity ρ_∑, use weighted mean method, ρ_∑=α₁ρ₁+α₂ρ₂+…α_nρ_n, and α₁+α₂+…α_n=1, α₁,α₂…α_nFor correspondence Test point weights, ρ₁,ρ₂,…ρ_nResistivity for corresponding grounded screen soil testing point.

The power station of a kind of karst area geomorphic feature or the acquisition of grounding net of transformer substation resistance value Method, it is characterised in that the resistance value method of described calculating main grounding grid is as follows: main grounding grid use level lay grounding body and Vertical ground connection, combines the composition main grounding device of combined type artificial, and main grounding body separates with the grounding body of lightning arrester；Tiling sets and connects Terrain uses Hot-dip zinc-coated flat steel sheet to be welded, and Grounding Grids uses hot galvanized steel pipe to be evenly distributed on the surrounding in grounded screen place And central point, the resistance of level laying grounding body is:

The resistance of Grounding Grids is:

Resistance between level laying grounding body welds with Grounding Grids is:

In formula (1)-(3), Lc is grounded screen mesh conductor length, and Lr is the length that grounded screen Grounding Grids every is excellent, and a is water Tiling sets the diameter of grounding body, and b is the diameter of Grounding Grids,A ＇ is conductor value, and wherein, h is main grounding grid Thickness, A be main grounding grid cover area, nr is the number of conductors of main grounding grid, and k1, k2 are regulation coefficient, true by following formula Fixed:

In formula, x, y are respectively grounded screen length and width.

The power station of a kind of karst area geomorphic feature or the acquisition of grounding net of transformer substation resistance value Method, it is characterised in that described subsidiary grounding grids can use " exogenous ", " compound building " or " deeply visiting formula ".

The power station of a kind of karst area geomorphic feature or the acquisition of grounding net of transformer substation resistance value Method, described " exogenous " uses extension subsidiary grounding grids to be connected with main grounding grid, and extension subsidiary grounding grids uses high-efficient graphite Earthing module；Extension subsidiary grounding grids symmetrical main grounding grid surrounding；High-efficient graphite earthing module quantity calculating ω= Ceiling[(ρ_∑λ/Rk), 1], take its higher limit；It is big that the method is mainly used in station address, and open, extension subsidiary grounding grids Resistance

In formula (6), λ is that ground connection cheats diameter, and numerical value is provided by high-efficient graphite earthing module manufacturer；R is ground grid design requirement Value；K is regulation coefficient, and span is 0.6-0.9；R_ωIt it is the resistance of monolithic high-efficient graphite earthing module.

The power station of a kind of karst area geomorphic feature or the acquisition of grounding net of transformer substation resistance value Method, it is characterised in that described " compound building " uses upper and lower two-layer stereo grounding mesh, place backfill before, original ground it Under, lay subsidiary grounding grids, press grid organization with zinc-coated flat steel sheet, add vertical grounding electrode in edge zone, adopt in grounded screen side Make ground lead with zinc-coated flat steel sheet to be connected with upper strata main grounding grid.Upper strata main grounding grid uses zinc-coated flat steel sheet to press grid organization, applies Be located at below designed elevation, between levels, upper strata grounding body and each building ensure safe distance.The method is mainly applied In site, floor space is little, and is petrographic province, " compound building " subsidiary grounding grids resistance

The power station of a kind of karst area geomorphic feature or the acquisition of grounding net of transformer substation resistance value Method, it is characterised in that described " deeply visiting formula " uses the mode beating ion earthing deep-well, along the periphery of grounded screen, chooses installation Vertical ion ground connection well, in parallel with station district main grounding grid.Electric operation platform and around laying cement gravel ground simultaneously, in order to Improve subsurface resistivities, reduce the person and undertake voltage.For preventing the impact of transfer voltage, lead to the pipeline outside station and all use absolutely Edge.The modes such as doorway, the station employing hat brim type equal pressure zone process that the personnel such as gate are more, improve the safety of ground connection further, Subsidiary grounding grids resistance of " deeply visiting formula "

The power station of a kind of karst area geomorphic feature or the acquisition of grounding net of transformer substation resistance value Method, it is characterised in that the described power station of calculating karst area geomorphic feature or the resistance value of grounding net of transformer substation are R_f// R_g。