一、基本条件
1、电缆结构
名称 所在层 材料 内径(mm) 厚度(mm) 外径(mm) 截面积(mm^2)
导体 导体 铜 0.0 0.0 23.8 368.0
导体屏蔽 绝缘 半导电材料 23.8 0.8 25.4 61.8
绝缘 绝缘 交联聚乙烯 25.4 0.6 26.6 49.0
绝缘屏蔽 绝缘 半导电材料 26.6 4.5 35.6 102.0
内护(导体) 内护层 铜带 35.6 0.2 36.0 22.5
内护(非金属) 内护层 聚氯乙烯护套 36.0 0.2 36.4 22.7
铠装 外护层 钢带铠装 36.4 0.0 36.4 0.0
外护 外护层 聚氯乙烯护套 36.4 2.3 41.0 112.6
2、运行状况
电流类型：三相交流
电压等级：35kV
电缆数量：3
中心点坐标(mm)：X = 500.00, Y = 500.00
回路间距(mm)：100.00
电缆间距(mm)：100.00
3、电缆敷设方式、环境条件和运行状况
敷设条件：空中
干燥和潮湿土壤热阻系数之比率：1.0
干燥土壤的热阻系数：1.0
自然土壤的热阻系数：1.0
土壤临界温度(℃)：40.0 ℃
环境温度(℃)：40.0 ℃
土壤临界温升(℃)：40.0 ℃
二、载流量计算
1、交流电阻
(1)导体最高工作温度下单位长度直流电阻
已知:R0 = 0.000047 Ω/m α20 = 0.003930 1/k θ = 90.0 ℃
结果:R' = 0.000060 Ω/m
(2)集肤效应因数
已知:f = 50 Hz R' = 0.000060 Ω/m ks = 1.000
结果:xs2 = 2.096852
结果:ys = 0.022488
(3)邻近效应因数
已知:f = 50 Hz R' = 0.000060 Ω/m kp = 0.80
结果:xp2 = 1.677482
不等距时
已知:dc = 23.8 mm s = 100.0 mm
结果:yp = 0.003418
(4)交流电阻
已知:R' = 0.000060 Ω/m ys = 0.022488 yp = 0.003418
结果:R' = 0.000061 Ω/m
2、绝缘损耗
(1)导体电容
已知:ε = 2.5 Di = 26.6 mm dc = 23.8 mm
结果:c = 1.249e-009 F/m
(2)绝缘损耗
已知:ω = 314.2 rad/s c = 1.249e-009 F/m U0 = 20207.26 V tgδ = 0.004
结果:Wd = 0.640748 W/m
3、金属套或屏蔽中的功率损耗
(1)最高工作温度下电缆单位长度金属套或屏蔽的电阻
已知:ρs = 1.724e-008 Ω•m As = 0.000022 m2 αs = 0.003930 1/K
θ = 90.0 ℃ η = 0.90
结果:Rs = 0.000950 Ω/m
(2)β1
已知:ω = 314.159265rad/s ρs = 1.724100e-008 Ω•m
结果:β1 = 151.320805
(3)gs
已知:ts = 0.2mm Ds = 36.0mm β1 = 151.320805
结果:gs = 1.000458
(4)m
已知:ω = 314.159265rad/s Rs = 0.000950Ω/m
结果:m = 0.033071
(5)滞后相涡流损耗
λ0、△1、△2
已知:m = 0.033071 d = 35.8mm s = 100.0mm
结果:λ0 = 0.000053 △1 = 0.022337 △2 = 0.000000
涡流损耗
结果:λ1'' = 0.000831
(6)中间电缆涡流损耗
λ0、△1、△2
已知:m = 0.033071 d = 35.8mm s = 100.0mm
结果:λ0 = 0.000210 △1 = 0.000007 △2 = 0.000000
涡流损耗
结果:λ1'' = 0.003248
(7)越前相涡流损耗
λ0、△1、△2
已知:m = 0.033071 d = 35.8mm s = 100.0mm
结果:λ0 = 0.000053 △1 = 0.013723 △2 = 0.000000
涡流损耗
结果:λ1'' = 0.000824
(9)金属套或屏蔽环流损耗
结果:λ1' = 0
(10)金属套或屏蔽功率损耗
结果:三相中最大的λ1 = 0.003248
4、铠装损耗因数
已知:无铠装
结果:λ2 = 0
5、电缆绝缘热阻T1
已知:ρT = 3.5 K•m/W t1 = 5.9 mm dc = 23.8 mm
结果:T1 = 0.224299 K•m/W
6、金属套和铠装之间热阻T2
已知:ρT = 6.0 K•m/W t2 = 0.2 mm Ds = 36.0 mm
结果:T2 = 0.010552 K•m/W
7、外护层热阻T3
已知:ρT = 6.0 K•m/W t3 = 2.3 mm Da' = 36.4 mm
结果:T3 = 0.113640 K•m/W
8、电缆外部热阻T4
(1)散热系数h
已知:Z = 0.62 E = 1.95 g = 0.25
De = 0.0410 m
结果:h = 3.328
(2)△θd
已知:Wd = 0.640748 W/m λ1 = 0.003248 λ2 = 0.000000
T1 = 0.224299 K•W/m T2 = 0.010552 K•W/m
n = 1
结果:△θd = 0.071394 K
(3)KA
已知:T1 = 0.224299 K•W/m T2 = 0.010552 K•W/m T3 = 0.113640 K•W/m
λ1 = 0.003248 λ2 = 0.000000
n = 1 De = 0.0410 m
结果:KA = 0.149066
(4)超过环境温度以上的电缆表面温升△θs
已知:△θ = 50.0 K △θd = 0.071394 K
KA = 0.149066 △θs0.25初值 = 2.0
结果:△θs0.25 = 2.460223 K
(5)T4
结果:T4 = 0.948267 K•W/m
9电缆额定载流量I
已知:交流电阻R = 0.000061 Ω/m
金属屏蔽损耗λ1 = 0.003248
铠装损耗λ2 = 0.000000
介质损耗Wd = 0.640748 W/m
热阻T1 = 0.224299 K•m/W
热阻T2 = 0.010552 K•m/W
热阻T3 = 0.113640 K•m/W
热阻T4 = 0.948267 K•m/W
结果:I = 784.831854 A
护套感应电压计算书
1.计算护套感应电压的中间参数Xs
已知:f = 50.000000 Hz Ds = 36.000000 mm S = 100.000000 mm
结果:Xs = 0.000108 Ω/m
2.计算护套感应电压的中间参数Xm
已知:f = 50.000000 Hz
结果:Xm = 0.000044 Ω/m
3.电缆护套感应电压U
已知:I = 784.831854 A Xs = 0.000108 Ω/m Xm = 0.000044 Ω/m
结果:U = 0.105874 Ω/m
电缆绝缘厚度计算书
1.计算电缆绝缘厚度的中间参数—老化系数
已知:t = 30.000000 年 n = 9.000000
结果:K2 = 4.001111
2.(按AC)计算电缆绝缘厚度
已知:Eo = 20.207259 kV K1 = 1.100000 K2 = 4.001111 K3 = 1.100000 Elac = 30.000000 kV/mm
结果:Tac = 3.261000 mm
3.(按冲击电压)计算电缆绝缘厚度
已知:BIL = 550.000000 kV I1 = 1.250000 I2 = 1.100000 I3 = 1.100000 EIimp = 60.000000 kV/mm
结果:Timp = 13.865000 mm
4.(最终结果)计算电缆绝缘厚度
已知:Tac = 3.261000 mm Timp = 13.865000 mm
结果:Timp = 14.900000 mm
电缆导体短路电流计算书
1.计算电缆导体短路电流中间参数(K)——载流体常数
已知:σc = 3450000.000000 J/K.m3 β = 254.452926 ρ20 = 0.000000 Ω.m
结果:K = 741.075156 As1/2/mm2
2.计算电缆导体短路电流
已知:K = 741.075156 As1/2/mm2 S = 368.000000 mm2 t = 3.000000 秒
θf = 250.000000 ℃ θi = 90.000000 ℃ β = 254.452926
结果:I = 97.300000 KA/3S
电缆金属屏蔽短路电流计算书
1.计算电缆金属屏蔽短路电流中间参数(K)——载流体常数
已知:σ = 2500000.000000 J/K.m3 β = 254.452926 ρ = 0.000000
结果:K = 630.845067
2.计算电缆金属屏蔽短路电流
已知:K = 630.845067 As1/2/mm2 S = 368.000000 mm2 t = 3.000000 秒 θf = 200.000000 ℃
θi = 90.000000 ℃ β = 254.452926 ε= 1.200000
结果:I = 84.700000 KA/3S
电缆使用过程中电动力计算书
1.电缆使用过程中电动力最大值
已知:S = 1.000000 mm lm = 97300.000000 A/1S cosωt - 31/2cosωt = 31/2(最大值)
结果:F = 1420.093500 N/m
2.电缆使用过程中电动力最小值
已知:S = 1.000000 mm lm = 97300.000000 A/1S cosωt - 31/2cosωt = 31/2/2(最小值)
结果:F = 710.046750 N/m
电缆工井长度计算书
1、电缆温升后电缆伸长量
(1)临界温度t计算
已知:A = 368.000000 mm2 E = 30000.000000 N/mm2 α= 0.000020 l/℃ μ= 0.300000
W = 161.300000 N/m L = 150.000000 m f = 1000.000000 N
结果:t = 41.930000 ℃
(2)按电缆弯曲半径要求计算温升65℃时
已知:t = 65 A = 368.000000 mm2 E = 30000.000000 N/mm2 α= 0.000020 l/℃ μ= 0.300000
W = 161.300000 N/m L = 150.000000 m f = 1000.000000 N
结果:m = 0.060000 m
(3)按电缆弯曲半径要求计算温升25℃时
已知:t = 25 A = 368.000000 mm2 E = 30000.000000 N/mm2 α= 0.000020 l/℃ μ= 0.300000
W = 161.300000 N/m L = 150.000000 m f = 1000.000000 N
结果:m = 0.000000 m
2、工井内电缆弯曲段长度S计算
(1)220KV单芯XLPE电缆允许最小施工弯曲半径R0
已知:D = 0.041000 m
结果:R0 = 0.820000 m
(2)电缆工井试算长度S
已知:R0 = 0.820000 m C = 0.500000 m
结果:R0 = 1.200000 m
(3)修正施工弯曲半径R0
已知:S = 1.200000 m C = 0.500000 m
结果:R0 = 0.850000 m
(4)修正相邻工井间电缆距离La
已知:S = 1.200000 m C = 0.500000 m
结果:La = 1.300000 m
(5)修正计算过程中间变量θ0
已知:S = 1.200000 m C = 0.500000 m
结果:θ0 = 0.789582
(6)修正计算过程中间变量B0
已知:R0 = 0.850000 m θ0 = 0.789582
结果:B0 = 0.065370 m
(7)修正计算过程中间变量B1
已知:m = 0.060000 m B0 = 0.065370 m La = 1.300000 m
结果:B1 = 0.110300 m
(8)验证S是否合理的阶段性结果R1
已知:B1 = 0.110300 m La = 1.300000 m
结果:R1 = 0.533958 m
(9)S本次试算时的取值
已知:S = 1.200000 m
结果:S = 1.200000 m
(10)S下次试算时的取值(可能不采用)
已知:S = 1.200000 m Step = 0.3 m
结果:S = 1.500000 m
(11)修正施工弯曲半径R0
已知:S = 1.500000 m C = 0.500000 m
结果:R0 = 1.250000 m
(12)修正相邻工井间电缆距离La
已知:S = 1.500000 m C = 0.500000 m
结果:La = 1.581000 m
(13)修正计算过程中间变量θ0
已知:S = 1.500000 m C = 0.500000 m
结果:θ0 = 0.643501
(14)修正计算过程中间变量B0
已知:R0 = 1.250000 m θ0 = 0.643501
结果:B0 = 0.064130 m
(15)修正计算过程中间变量B1
已知:m = 0.060000 m B0 = 0.064130 m La = 1.581000 m
结果:B1 = 0.117100 m
(16)验证S是否合理的阶段性结果R1
已知:B1 = 0.117100 m La = 1.581000 m
结果:R1 = 0.725598 m
(17)S本次试算时的取值
已知:S = 1.500000 m
结果:S = 1.500000 m
(18)S下次试算时的取值(可能不采用)
已知:S = 1.500000 m Step = 0.3 m
结果:S = 1.800000 m
(19)按电缆弯曲半径要求试算的结果S
已知:S = 1.500000 m
结果:S = 1.500000 m
按保护层疲劳限制核算畸变量并根据结果再次试算S
(20)按保护层疲劳限制核算畸变量ε
已知:S = 1.500000 m C = 0.500000 m d = 0.035800 m m = 0.000000 m
结果:ε = 0.000000 m
(21)S本次试算时的取值
已知:S = 1.500000 m
结果:S = 1.500000 m
(22)S下次试算时的取值(可能不采用)
已知:S = 1.500000 m Step = 0.3 m
结果:S = 1.800000 m
(23)按保护层疲劳限制试算的结果S
已知:S = 1.500000 m
结果:S = 1.500000 m
3、工井长度
已知:S = 1.500000 m 电缆接头长 = 2.000000 m
结果:工井长度 = 5.600000 m