接地電阻的計(jì)算

工頻接地電阻計(jì)算,,,,,,,

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1、垂直接地體的接地電阻R的計(jì)算：當(dāng)l>>d時(shí)，R=ρ/(2πL)×(ln(4L/d)-0.31),,,,,,,

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,ρ,L,b,b1,b2,d,R

對(duì)于扁鋼,2,10,0.04,,,0.02,0.232194346

對(duì)于角鋼,500,10,3,0.05,0.05,0.042216853,52.10043982

圓鋼（管）,1000,100,,,,0.1,12.71345484

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1.1、土壤電阻率ρ的計(jì)算,,,,,,,

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,R,L,b,b1,b2,d,ρ

對(duì)于扁鋼,30,1,0.16,,,0.05,46.26688794

對(duì)于角鋼,10,2,3,0.05,0.05,0.042216853,25.45407285

圓鋼（管）,10,1,0.05,,,0.05,15.42229598

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1.1.1、當(dāng)角鋼為0.05×0.05×1m長和0.05×0.05×2m長時(shí)的電阻率ρ：,,,,,,,

k角=2πL/(ln(4L/d)-0.31)ρ=k角×R,,,,,,,

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,R,L,b1,b2,d,K,ρ

對(duì)于角鋼,10,1,0.05,0.05,0.042216853,1.48070248,14.8070248

對(duì)于角鋼,10,2,0.05,0.05,0.042216853,2.545407285,25.45407285

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當(dāng)角鋼為0.05×0.05×1m長時(shí)的電阻率ρ為：,,,,14.8070248,,,

當(dāng)角鋼為0.05×0.05×2m長時(shí)的電阻率ρ為：,,,,25.45407285,,,

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1.1.2、當(dāng)圓鋼為d=0.08×1m長和d=0.08×2m長時(shí)的電阻率ρ：,,,,,,,

k圓=2πL/(ln(4L/d)-0.31)ρ=k圓×R,,,,,,,

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,R,L,d,K,ρ,,

圓鋼（管）,240,100,0.16,83.57681056,20058.43453,,

圓鋼（管）,10,2,0.08,2.924214747,29.24214747,,

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當(dāng)圓鋼為0.08×1m長時(shí)的電阻率ρ為：,,,,20058.43453,,,

當(dāng)圓鋼為0.08×2m長時(shí)的電阻率ρ為：,,,,29.24214747,,,

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其中：ρ——土壤電阻率(Ωm)；,,,,,,,

L——垂直接地體的長度(m)；,,,,,,,

d——垂直接地體的等效直徑（m）。,,,,,,,

對(duì)于扁鋼d=b/2，b為扁鋼寬度；,,,,,,,

對(duì)于角鋼d=0.71×(4√(b1×b2×(b12+b22))，b1、b2為角鋼邊長；,,,,,,,

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,,,,圖為：垂直接地體,,,

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2、不同形狀水平接地體的接地電阻R的計(jì)算：R=ρ/(2πL)×(ln(L2/(hd))+A),,,,,,,

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,ρ,L,h,d,A,R,

,2000,5000,1,0.03,5.65,1.668213011,

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h——水平接地體的埋設(shè)深度(m)；,,,,,,,

d——水平接地體的直徑或等效直徑(m);,,,,,,,

A——水平接地體的形狀系數(shù)。,,,,,,,

水平接地體的形狀系數(shù)可采用下表所列數(shù)值：,,,,,,,

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形狀,,,,,,,

A,5.65,3.03,1,0.89,0.48,0,—0.18—0.6

3、以水平接地體為主，且邊緣閉合的復(fù)合接地體，其接地電阻的計(jì)算：,,,,,,,

R=(0.22-0.007L1/L2)×ρ/(√(L1×L2))×(1+B)+ρ/(2πL)×(LN((L1×L2)/(9hd))-5B)B=1/(1+4.6h/(√L1×L2)),,,,,,,

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ρ,L1,L2,d,L,h,B,R

1000,400,200,3,700000,20,0.754563722,1.278162575

其中：L1、L2——分別為地網(wǎng)水平投影長度、寬度(m)，L1、L2≤8；,,,,,,,

L——接地體的總長度，包括垂直接地體在內(nèi)(m)；,,,,,,,

d——水平接地體的直徑或等效直徑(m)；,,,,,,,

h——水平接地體的埋設(shè)深度(m)。,,,,,,,

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