海缆载流量计算
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110 kV
300mm 2
1
1.1油道
D 油=19.5mm 1.2螺旋管D 螺=22.5mm 1.3导体D 导=
32.5mm 1.4导体屏蔽δ内屏=
0.5mm D 内屏=33.5mm 1.5油纸绝缘δ绝=
10.5mm D 绝=54.5mm 1.6绝缘屏蔽δ
外屏=0.6mm D 外屏=55.7mm 1.7铅护套δ铅=4mm D 铅=63.7mm 1.8衬垫层δ衬=0.75mm D 衬=65.2mm 1.9不锈钢带δ不=0.3mm D 不=65.8mm 1.10防水层δ防=0.8mm D 防=67.4mm 1.11PE 护套δ护=
3.5mm D 护=7
4.4mm 1.12麻+沥青δ
内麻= 2.5mm D 内麻=79.4mm 1.13铠装层δ铠=6mm D 铠=91.4mm 1.14沥青δ
沥=
0.5mm D 沥=92.4mm 1.15麻+沥青δ外麻= 2.5mm D 外麻=97.4mm 1.16PVC 带
δPVC =
0.2
mm
D PVC =
97.8
mm
2
2.1
海中段S=200m 陆上段
S=
300
mm
2.2
海中段L=1m 陆上段L=1m 2.3ρt =
1
K.m / W
2.42.5
土壤:θ0=25℃空气:θ0=
35
℃海水:
θ0=
20
℃
33.1
3.1.1在20℃时直流电阻
R 0=
0.0601
Ω / km =
6.01E-05Ω / m
充油海缆载流量及其它参数计算
电缆结构
敷设条件
敷设间距
埋设深度
两端接地
土壤热阻系数接地方式
环境最高温度
载流量计算
导体损耗计算
3.1.2在85℃时直流电阻R'=
7.5453E-05Ω / m
3.1.3
66单线外径:
2.49
mm
d i = 1.95cm
A= 3.213898cm 2d c '= 2.809727cm
k s =0.35894189
X s 2=
0.59780529Y s =X s 4/(192+0.8*X s 4)=0.00185854
3.1.4
k s =0.8d c =
3.25cm
X p 2= 1.33237229
海中段:
Y p =X p 4/(192+0.8*X p 4)*(d c /S)2{0.312(d c /S)2+1.18/[X p 4/(192+0.8X p 4)+0.27]} = 1.02437E-09
陆上段:
Y p =X p 4/(192+0.8*X p 4)*(d c /S)2{0.312(d c /S)2+1.18/[X p 4/(192+0.8X p 4)+0.27]} = 4.5528E-06
3.1.5海中段:
R=7.5593E-05Ω / m 陆上段:R=7.5593E-05Ω / m
3.1.6要求的载流量
P=100MW I n =P/(30.5U)=
524.8638811A 3.1.7每相导体损耗W c =I n 2R=
20.824551W / m
3.23.2.1电缆电容C
ε= 3.6
C=ε/[18*ln(D 外屏/D 导)]*10-9= 4.1097E-10F / m
3.2.2每相介质损耗
tg δ=0.0033W d =ωCU 02tg δ=
1.718446962W / m
3.2.3单回路充电容量
P c =30.5
ωCU 02
=901.9507419VA / m 3.3
便,取陆上段的R 值
介质损耗因素R’(1+Y s +Y p )=
海中段和陆上段的R 误差很小,为计算方
单线根数:π/4*单线外径2*单线根数 =
R 0*[1+α
20*(85-20}]=
计算集肤效应因素
8πf/R'*10-7*k p =
(4/π*A+d i 2)^0.5 =(d c '-d i )/(d c '+d i )*[(d c '+2*d i )/(d c '+d i )]2 =
8πf/R'*10-7*k s =
计算邻近效应因素
导体在85℃时交流电阻
R’(1+Y s +Y p )=金属护套、钢丝铠装层损耗
3.3.1总损耗
a)金属护套、加强层并联电阻铅护套电阻
A s1=7.502117cm 2
ρs1=0.0000214Ω . cm
θ
s1=
70℃
α
s1=
0.004
R s1= 3.42E-06Ω / cm
=0.000342303Ω / m
加强层电阻
A s2=0.617322cm 2ρ
s2=
0.00007Ω . cm
R s2=0.000227Ω / cm
=0.022678586Ω / m
并联电阻
R s =0.00033721Ω / m
b)铠装层电阻钢丝电阻
钢丝:36
根铜丝:7根
θa1=65℃
ρ
a1= 1.38E-05Ω . cm
A a1=
10.17875cm 2R a1= 1.63E-06Ω / cm
=0.000163031Ω / m
隔离铜丝电阻
θa2=65℃
ρ
a2=
1.72E-06Ω . cm A a2=
1.979202cm 2
R a1= 1.03E-06Ω / cm =0.000102516Ω / m
并联电阻
R a =7.0742E-05Ω / m
c)每相回路护套产生电感海中段:
d=D 铅-δ铅=59.7mm
H s =
1.76E-08H /cm = 1.76E-06H / m 陆上段:H s = 4.61E-09H /cm = 4.61E-07H / m d)钢丝产生的电感分量
μe =400μ1=
43d f =
0.6
cm d A =
8.54cm
μt =
1γ=0.785398
钢丝节径比
h=
13
0.46(lg(2S/d)*10-8=
0.46(lg(2S/d)*10-8=
ρa1/A a1[1+αa 1(θa1-20)]=
π/4*铜丝直径2*铜丝根数 =
ρa1/A a1[1+αa 1(θa1-20)]=1.4R a1*R a2/(1.4R a1+Ra 2)=R s1*R s2/(R s1+Rs 2) =
铠装层结构:π/4*钢丝直径2*钢丝根数 =
π/4*(D 铅2-D 外屏2) =
ρs1/A s1[1+αs1(θs1-20)]=π/4*(D 不2-D 衬2) =
2ρs2/A s2=
β=arctg(h/π)= 1.33368162P=
h*d A =111.02cm H 1= 1.4095E-08H / cm = 1.40949E-06H / m H 2= 1.4095E-08
H / cm = 1.40949E-06H / m
H 3=0H / cm =
H / m
e)海中段总损耗:
B 1=0.00099572
Ω / m B 2=0.0004428Ω / m R e =
5.8475E-05
Ω / m
W (s+A)=15.728879W / m
d)陆上段总损耗:
B 1=0.00058763Ω / m
B 2=0.0004428Ω / m R e = 5.8475E-05
Ω / m
W (s+A)=15.3173587W / m
3.3.2铅护套损耗λ1和铠装层损耗λ
2
海中段:λ1=λ2=
λ1’=λ2’=
0.377652陆上段:
λ1=λ2=λ1’=λ2’=0.367772
3.43.
4.1绝缘热阻T 1:
ρt1=5
K.m / W
T 1=
0.42871608K.m / W
3.4.2热阻T 2:
a)包带和内护层热阻T 2’
ρ't2'=6K.m / W
ρ't2''=
3.5K.m / W
T'2=
0.108958K.m / W
b)内油麻热阻T 2''
ρ''t2=6K.m / W
T''2=
0.06211099K.m / W c)热阻T 2:
T 2=T'2+T''2=
0.171068714K.m / W
3.4.4外油麻热阻T 3:
ρt3=6K.m / W
T 3=
0.06462883K.m / W
热阻计算ρt1/2/π*ln(D 外屏/D 导)=
ρ't2'/2/π*ln(D 防/D 铅)+ρ't2''/2/π*ln(D 护/D 防)=
ρt1/2/π*ln(D 内麻/D 护)=
ρt3/2/π*ln(D 电缆/D 铠)=
ωH 2 =R s *R a /(R s +R a ) =
I 2{R e *(B 22+B 12+R e B 2)/[(R e +B 2)2+B 12]} =
W (s+A)/2/W c =W (s+A)/2/W c =
0.314μe(μ1*d f 2/P/d A )sin βcos γ*10-8 =0.314μe(μ1*d f 2/P/d A )sin βsin γ*10-8 =I 2{R e *(B 22+B 12+R e B 2)/[(R e +B 2)2+B 12]} =
0.4(μt -1)*d f /d A cos 2β*10-8 =
ω(H s +H 1+H 3) = ωH 2 =R s *R a /(R s +R a ) =
ω(H s +H 1+H 3) =
3.4.5土壤热阻T 4:
a)海中段:
ρt4=
0.8K.m / W D e =97.8mm =0.0978m
u=
2L / D e =
20.44989775
T 4=
0.472439
K.m / W
b)陆上段:
ρt4=
1K.m / W D e =97.8mm =0.0978m
u=
2L / D e =
20.44989775
S1=
0.3
m
T 4= 1.19796302K.m / W
c)空气段(受光照):
Z=0.21E= 3.94
g=
0.6
h=Z/D e g +E =
4.787258592W / m 2(K)6/4
n=
1K A =0.656698Δθd =
-0.00616
H=1000
W / m 2
Δθ=
50
℃
ζ=
0.8Δθ
ds =
=34.93168391
(Δθd )1/4=
2.3(Δθd )1/4= 2.4117015(Δθd )1/4= 2.39439884(Δθd )1/4= 2.39703857(Δθd )1/4= 2.3966349(Δθd )1/4= 2.39669661(Δθd )1/4= 2.39668718(Δθd )1/4
= 2.39668862(Δθd )1/4=
2.3966884
T 4=0.28366985K.W / m
3.53.5.1海中段:
I={[Δθ-W d (0.5T 1+T 2+T 3+T 4)]/R/[T 1+(1+λ1)T 2+(1+λ1+λ2)(T 3+T 4)]}1/2 =727.0995519A
3.5.2陆上段:
I={[Δθ-W d (0.5T 1+T 2+T 3+T 4)]/R/[T 1+(1+λ1)T 2+(1+λ1+λ2)(T 3+T 4)]}1/2 =514.7657435A
3.5.3空气段(受光照):
Wd{[1/(1+λ1+λ2)-0.5]T1-n λ2T2/(1+λ1+λ2)}=ρt4/2/π*ln[u+(u 2-1)0.5]=ρt4/2/π*{ln[u+(u 2-1)0.5]+ln[1+(2L/S 1)2]}=
π*D e *h/(1+λ1+λ2)[T 1/n+T 2(1+λ1)+T 3(1+λ1+λ2)]=ζD e H/(1+λ1+λ2)[T 1/n+T 2(1+λ1)+T 3(1+λ1+λ2)]{(Δθ+Δθd +Δθds )/[1+K A (Δ
θs )1/4]1/4 ={(Δθ+Δθd +Δθds )/[1+K A (Δθs )1/4]1/4
={(Δθ+Δθd +Δθds )/[1+K A (Δθs )1/4]1/4 ={(Δθ+Δθd +Δθ
ds )/[1+K A (Δ
θs )1/4]1/4 =
1/[πD e h(Δθs )1/4]=
载流量{(Δθ+Δθd +Δθds )/[1+K A (Δθs )1/4]1/4 ={(Δθ+Δθd +Δθds )/[1+K A (Δ
θs )1/4]1/4 ={(Δθ+Δθd +Δθds )/[1+K A (Δθs )1/4]1/4 ={(Δθ+Δθd +Δθds )/[1+K A (Δθs )1/4]1/4
=
I={[Δθ-W d (0.5T 1+T 2+T 3+T 4)-ζD e HT 4]/R/[T 1+(1+λ1)T 2+(1+λ1+λ2)(T 3+T 4)]}1/2 =589.3503313A
4E max =7.791047 kV / mm E min =
4.788992 kV / mm
55.1已知条件
S=
300
mm 2
θf =160℃K=226θi =85℃X=0.45Y=
0.14
β=
234.5
5.2
t sc =1
ε=[1+X (t/S)1/2+Y(t/s)]1/2=
1.01313742
5.3计算I AD
I AD =
31133.56
A = 31.13356
kA
5.4计算I SC
I SC =
εI AD =
31.54256979
kA
66.1已知条件
S=750.211692mm 2θf =160℃F=1K=41θi =75℃β=
230
ζ2=2000000
J / K.m ζ3=1700000
J / K.m
ρ2=5K.m / W ρ3=6K.m / W ζ1=
1450000
J / K.m
δ =
4
mm
M=0.1004096.2
ε=
1.06055828
6.3计算I AD
I AD =
15250.69A = 15.25069
kA
6.4计算I SC
I SC =
εI AD =
16.17424612
kA
77.1
lnGMRc=ln(D 导/2)-(D 螺/2)4/[(D 导/2)2-(D 螺/2)2]2*ln(D 导/D 螺)
电场强度
U 0/[D 内屏/2*ln(D 绝/D 内屏)=U 0/[D 绝/2*ln(D 绝/D 内屏)=
导体短路电流计算
正、负序阻抗计算
非绝热因素非绝热因素线芯几何平均半径GMRc
铅护套短路电流计算
[(ζ2/ρ2)1/2+(ζ3/ρ3)1/2] /(2ζ1δ*0.001)*F =1+0.61M*t 1/2-0.069(M*t 1/2)2+0.0043(M*t 1/2)3 ={K 2S 2ln[(θf +β)/(θi +β)]/t}1/2=
{K 2S 2ln[(θf +β)/(θi +β)]/t}1/2=
+[3(D 螺/2)2-(D 导/2)2]/{4[(D 导/2)2-(D 螺/2)2]} = 2.6867703
GMRc=e lnGMRc =14.68417378mm 7.2
lnGMRs=ln(D 铅/2)-(D 外屏/2)4/[(D 铅/2)2-(D 外屏/2)2]2*ln(D 铅/D 外屏)
+[3(D 外屏/2)2-(D 铅/2)2]/{4[(D 铅/2)2-(D 外屏/2)2]} = 3.419247207
GMRs=e lnGMRs =30.54641123mm
7.3
n=1m=2S=200000
mm
Xm=Xs=
j
0.56660914Ω / km
7.4Z 1=Z 2=R c +Xm 2R s /(Xm 2+R s 2)+ j 2ω*10-4ln[(nm)1/3S/GMRc]- j Xm 3/(Xm 2+Rs 2)
=0.32637064 + j 0.19752409Ω / km
8
8.1X c =j
0.01534079Ω / km
8.2
ρ
大地=
30Ω .m D e =
513763.8mm
X m =0.23363096Ω / km
8.3
R g =π2f*10-4=0.049347939Ω / km R c +3X c =
0.07559312
+ j 0.04602238Ω / km 0.050675899 + j 0.239918Ω / km 0.490347199
+ j
0.700893Ω / km 0.26378013 + j 0.11223962Ω / km
Z 0=
0.339373
+ j
0.158262Ω / km
9
9.1电缆内感L i
Li=μ0/(8*π)=
0.00000005
H / m 9.2电缆电感L
L=
1.9336E-06
H / m
求零序阻抗Z0金属护套和大地组成的感抗Xm 93.8*ρ
大地
1/2
*1000=j 2ω*10-4*ln[D e /(S 2/3(nm)2/9*GMRs 1/3]= j 铅护套几何平均半径GMRs
j 2ω*10-4*ln(GMRs/GMRc)1/3 =j 2ω*10-4*ln[(nm)1/3S/GMRs]=求正负序阻抗Z 1、Z 2
求Xm 、Xs(海中段)因陆上段和空气段的长度与海中段相比可忽略不计
求零序阻抗Z 0
短路电流以金属护套为回路的自感抗Xc 求电缆电感L
Li+[2ln(2S/D c )]*10-7=
3R s (R g +X m ) =R s +3R g +3X m =3R s (R g +X m )/(R s +3R g +3X m ) =
R c +3X c +3R s (R g +X m )/(R s +3R g +3X m )=