XXXXXX光伏发电工程短路电流计算书审查:校核:编写:一、工程概况XXXXXXX光伏发电工程总装机50MWp,海拔高度约为1215m。本工程建成后出1回110kV线路接入1XXXXX变110kV侧。线路长约5.1km,选用LGJ-300型导线,变压器分列运行。二、技术参数1、110kV线路侧短路电流Imax=5.23kA2、主变压器B1容量SB1=50000kVA,Uk=10.5%,110/35kV3、35kV厂变B2容量SB1=160kVA,Uk=6%,35/0.4kV4、SVG变压器B3容量SB1=10000kVA,Uk=7.5%,35/10kV5、联合单元箱式变压器BN容量SBN=1000kVA(分裂变压器),Uk=6.5%,36.75/0.315/0.315kV,分裂系数Kf=3.5,半穿越阻抗X`1-2=12%常用基准值:Uj(kV)Ij(kA)1150.5371.5610.55.50.4144.300.315183.29三、系统阻抗图四、短路电流计算(1)已知系统短路电流Ixmax=5.23kAXx*=Ij/Ixmax=0.5/5.23=0.0956线路采用LGJ-300导线,线路电抗取Xl=0.4l=5.1kmXl*=X*Sj/Uj2=0.4*5.1*100/115=0.01542X*=0.0956+0.0154=0.111k1短路电流Ik1=Ij/X*=0.5/0.111=4.5kA(2)主变压器B1XB1=Uk%/100×100/SB1=10.5/100×100/50=0.21则k2点短路电流为:Ik2=Ij/(X*+XB1)=1.56/(0.111+0.21)=4.86kA(3)35kV厂变B2XB2=Uk%/100×100/SB2=6/100×100/0.16=37.5则k2点短路电流为:IkB2=Ij/(X*+XB1)=144.30/(0.111+0.21+37.5)=3.815kA(4)SVG变压器B3XB3=Uk%/100×100/SB2=7.5/100×100/10=0.75则k3点短路电流为:IkB3=Ij/(X*+XB1)=5.5/(0.111+0.21+0.75)=5.135kA(4)联合单元箱式变压器BN阻抗图X1-2=X`1-2/(1+Kf/4)=12%/(1+3.5/4)=6.4%Xf=Kf·X1-2=3.5×6.4%=22.4%则低压侧两支路电抗分别为:X2=X`2=1/2Xf=1/2×22.4%=11.2%高压侧支路电抗为:X1=(1-Kf/4)X1-2=(1-3.5/4)×6.4%=0.8%折合到100MVAX1=0.8%×100/1=0.8,X2=11.2%×100/1=11.2仅考虑单一支路短路时短路电流为:IkBN=Ij/(X*+XB1+X1+X2)=183.29/(0.111+0.21+0.8+11.2)=14.876kA表6-1短路电流计算结果表短路点母线名称XXXX变110kV母线XXXX光伏电站110kV母线K1XXXX光伏电站35kV母线K2XXXX光伏电站35kV厂变低压侧KB2三相短路电流(kA)5.234.54.863.815XXXX光伏电站SVG变低压侧KB35.135XXXXX光伏电站箱变低压侧KBN14.876