500kV变短路电流计算及设备选择(初设)

修改码:0计算书封面XX500kV变电站工程初步设计设计阶段电气专业短路电流计算及设备校验计算书批准人/日期：审核人/日期：校核人/日期：计算人/日期：电力设计院计算稿纸第2页一.系统阻抗:(基准容量:Sj=100MVA)远期：500kVX1=0.00211X0=0.0062220kVX1=0.0185X0=0.0114二.主变规范:类型：3×ODFS-334000/500三个单相自耦变压器单台容量比：334/334/100MVA电压比：kV36/%5.223230/3525接线组别：Yn,a0,d11短路电压：Uk1-2%=18Uk1-3%=58Uk2-3%=38T1*=(Uk1-2%+Uk1-3%-Uk2-3%)×Sj/(Se×100×2)=(18+58-38)×100/(1000×100×2)=0.019T2*=(Uk1-2%+Uk2-3%-Uk1-3%)×Sj/(Se×100×2)=(18+38-58)×100/(1000×100×2)=-0.001(舍去)T3*=(Uk1-3%+Uk2-3%-Uk1-2%)×Sj/(Se×100×2)=(58+38-18)×100/(1000×100×2)=0.039三.短路电流计算：(一)正序网络(远期按三组主变高、中侧并列运行)(1)d1点短路X∑=0.00211//(0.0185+0.0063)=0.0019Ij1=100/√3×525=0.11kAId1=Ij1/X∑=0.11/0.0019=56.5492kA(2)d2点短路X∑=0.0185//(0.00211+0.0063)=0.0058Ij2=100/√3×230=0.251kAId2=Ij2/X∑=0.251/0.0058=43.3002kA电力设计院计算稿纸第3页(3)d3点短路X∑=0.039+0.0185//(0.00211+0.0063)=0.0448Ij3=100/√3×37=1.5605kAId3=Ij3/X∑=1.5605/0.0448=34.8335kA(二)零序网络：终期3台主变并列运行（高、中压侧并联）(1)d1点短路X0∑=0.0062//[0.0063+(0.0114+0)//0.013]=0.0041X1∑=0.0019X(2)*=2X1∑=0.0039X(1)*=2X1∑+X0∑=0.0039+0.0041=0.008X(1,1)*=X1∑+X1∑×X0∑/(X1∑+X0∑)=0.0019+0.0019×0.0041/(0.0019+0.0041)=0.0033I(2)d=√3×0.11/0.0039=48.9716kAI(1)d=3×0.11/0.008=41.119kAI(1,1)d=√3×sqrt(1-X1∑×X0∑/(X1∑+X0∑)2)×Ij1/X(1,1)*=√3×sqrt(1-0.0019×0.0041/(0.0019+0.0041)2)×0.11/0.0033=51.5664kA(2)d2点短路X0∑=0.0114//[(0.0062+0.0063)//0.013]=0.0041X1∑=0.0058X(2)*=2X1∑=0.0116X(1)*=2X1∑+X0∑=0.0116+0.0041=0.0157X(1,1)*=X1∑+X1∑×X0∑/(X1∑+X0∑)=0.0058+0.0058×0.0041/(0.0058+0.0041)=0.0082I(2)d=√3×0.251/0.0116=37.498kAI(1)d=3×0.251/0.0157=48.0102kAI(1,1)d=√3×sqrt(1-X1∑×X0∑/(X1∑+X0∑)2)×Ij1/X(1,1)*=√3×sqrt(1-0.0058×0.0041/(0.0058+0.0041)2)×0.251/0.0082=46.1687kA电力设计院计算稿纸第4页四.导线、主设备选择取电流如下：1.500kVId1=56.55kAich=2.55×56.55=144.20kAIch=1.51×56.55=85.39kA2.220kVI(1)d=48.01kAich=2.55×48.01=122.43kAIch=1.51×48.01=72.50kA3.35kVId3=34.83kAich=2.55×34.83=88.82kAIch=1.51×34.83=52.59kA电力设计院计算稿纸第5页主设备选择校验一.条件1.年最大负荷利用小时数:500kV5000小时220kV5000小时35kV4000小时2.母线穿越功率:500kV母线为4600MVA220kV母线为1400MVA3.500kV开关串内最大穿越功率为3000MVA4.温度:(1)最热月平均最高温度:32.5oC(8月)(2)极端最高气温：40oC(1988.7.19)取40oC(3)极端最低气温：-20.6oC(1955.1.6)取-25oC5.50年一遇最大风速为21.3m/s,设计取30m/s.6.覆冰厚度10mm,冰比重为0.9g/cm37.短路电流的热效应时间:500kV220kV35kVtd断路器全分闸时间0.050.050.10tb1主保护动作时间0.060.060.10tb2后备保护动作时间0.560.560.60tfz非周期分量等效时间0.050.050.05tjs1电器热稳定计算时间0.660.660.75tjs2导体热稳定计算时间0.160.160.25二.导体选择及主要设备校验（一）500kV侧:1.主变进线:2×LGKK-600(1)按正常持续工作电流选择:Ig=1.3×Se/(√3Ue)×103=1501.1AIy=2IXU/B=2×1223/02.1=2422AB={1-[1+(1+1/4Z2)-1/4+10/20Z2]×Z2d0/(16+Z2)d}-1/2=1.02Z=4πλs/(ρ+1)=1.642K=)2580/()5.3280(=0.93Iy=KIy=0.93×2422=2252.4AIyIg(2)按经济电流密度选择:T=5000h查表j=0.78(A/mm2)Sj=Ig/j=1501.1/0.78=1924.5mm2(3)电晕电压校验:临界电晕电压U0=84m1m2kδ2/32r0(1+0.301/√r0δ)lg(ajj/rd)/k0=759.8kV(m1取0.9,m2取1)δ=2.895p10-3/(273+t)=0.982t=25-0.005H=25-0.00540=24.8k0=1+2r0sin(π/2)/d=1.1275U0=759.8kV550kV电力设计院计算稿纸第6页故选2LGKK-600导线满足要求.(4)热稳定校验:tjs2=0.16sId=56.55kAQd=Id2tjs2=56.5520.16=511.66kA2.S运行最高温度为80oC,查手册一表8-9得C’=83钢芯铝绞线C=C’87%=72.21S1000√Qd/C=1000511.66/72.21=313.25mm2小于所选截面故500kV主变进线选2×LGKK-600导线满足要求。2.间隔跨线校验:2×NAHLGJQ-1440根据系统提资，500kV开关串内最大穿越功率为3000MVA。(1)按正常持续工作电流选择:Ig=1.05×3000/(3×500)×103=3637.3AIy=2IXU/B=2×3236/005.1=6455.9AB={1-[1+(1+1/4Z2)-1/4+10/20Z2]×Z2d0/(16+Z2)d}-1/2=1.005Z=4πλs/(ρ+1)=4.02K=)25150/()5.32150(=0.97Iy=KIy=0.97×6455.9=6262.2AIyIg(2)按经济电流密度选择:T=5000h查表j=0.78(A/mm2)Sj=Ig/j=3637.3/0.78=4663.2mm22880mm2(3)电晕电压校验:临界电晕电压U0=84m1m2kδ2/32r0(1+0.301/√r0δ)lg(ajj/rd)/k0=765.08kV(m1取0.9,m2取1)δ=2.895p10-3/(273+t)=0.982t=25-0.005H=25-0.00540=24.8k0=1+2r0sin(π/2)/d=1.1284U0=765.08kV550kV故选2×NAHLGJQ-1440导线满足要求.(4)热稳定校验:tjs2=0.16sId=56.55kAQd=Id2tjs2=56.5520.16=511.66kA2.So=32.5℃H=150℃=o+(H-o)xuIgI22max=32.5+(150-32.5)222.62623.3637=72.1℃C’=410t1)]t2)/(Kln[(ττ=4610)]1.72452)/(002452ln[(10222=86.7(P337)C=C’0.87=86.70.87=75.4S1000√Qd/C=1000511.66/75.4=300.0mm2小于所选截面故选2×NAHLGJQ-1440导线满足要求。3.六氟化硫断路器校验(西电):-QF:SF64000A,63kA额定开断电流:63kA短路关合电流:160kA3热稳定电流:63kA电力设计院计算稿纸第7页动稳定电流:160kA(1)正常持续工作电流Ig=3637.3A(2)最高工作电压:Umax=550kV＞Ug(3)动稳定校验:ich=144.20kAigf=160kA＞ich满足要求(4)热稳定校验:已知tjs1=0.66sId=56.55kAQd=Id2tjs1=56.5520.66=2110.62kA2.S3”内允许通过热稳定电流I2×t=6323=11907kA2.SI2×tQd满足要求4.SF6电流互感器校验:(MWB)-BA:油浸式2×2000/1额定电流比：2×2000/1A动稳定电流峰值160kA3热稳定电流63kA(1)正常持续工作电流Ig=3637.3A2×2000A(2)动稳定校验:ich=144.20kAigf=160kAigf＞ich满足要求(3)热稳定校验:It2×t=6323＝11907kA2.SQd=2110.62kA2.S满足要求5.隔离开关校验:(1)-QS:4000A,63kA（双接地）(西门子)动稳定电流峰值160kA热稳定电流63kA（主刀2s、地刀1s）1)额定电流:Ig=3637.3A4000A2)最高工作电压:Umax=550kVUg3)动稳定校验:ich=144.20kAigf＞ich满足要求4)热稳定校验:主刀It2×t=6322=7938kA2.SQd=2110.62kA2.S地刀It2×t=6321=3969kA2.SQd=2110.62kA2.S(2)-QS:4000A,63kA(单接地)校验同上(3)-QSE:63kA动稳定电流峰值160kA1热稳定电流63kA1)最高工作电压:Umax=550kVUg3)动稳定校验:ich=144.20kAigf=160kA＞ich满足要求4)热稳定校验:电力设计院计算稿纸第8页It2×t=6321=3969kA2.SQd=2110.62kA2.S（二）220kV侧1.主变进线（母联）:2×NAHLGJQ-1440(1)按正常持续工作电流选择:Ig=1.3×Se/(√3Ue)×103=3411.6AIy=2IXU/B=2×3236/005.1=6455.9AB={1-[1+(1+1/4Z2)-1/4+10/20Z2]×Z2d0/(16+Z2)d}-1/2=1.005Z=4πλs/(ρ+1)=4.02K=)25150/()5.32150(=0.97Iy=KIy=0.97×6455.9=6262.2AIyIg(2)按经济电流密度选择:T=5000h查表j=0.78(A/mm2)Sj=Ig/j=3411.6/0.78=4373.9mm2(3)电晕电压校验:导线2×NAHLGJQ-