肯尼亚母线跨线短路动态张力计算.doc

肯尼亚母线跨线短路动态张力计算工程描述：本期肯尼亚220kv为单母线接线，母线采用双分裂铝绞线型号为2* aac-800，母线最大跨距34.8m。description of the project: 220kv is single bus connection, the bus is 2* aac-800, the maximum distance between the bus is 34.8m.计算依据：iec_60865-1-1993短路电流效应的计算the basis of the calculation: calculation of short-circuit current in iec_60865-1-1993计算断面及平面图如下：the section and plan of the calculation:.计算输入参数：1.1 common data220kv三相短路电流：i =31.5kathree-phase initial symmetrical short-circuit current(r.m.s) i =31.5ka短路电流开断时间：t=1sduration of the first short-circuit current t=1s母线跨度（考虑绝缘子串长度） l=33.8mdistance between supports l=33.8m耐张串和可调串长度分别为：3. 3m及3.6mthe length of one insulator chain and the adjustable length: 3. 3m and 3.6m导线短路工况时计算跨度：lc =33.8-3.6-3.3=26.9mlength of the conductor carrying short-circuit current lc =33.8-3.6-3.3=26.9m母线相间距离 a=4.5m。centre-line distance between phase conductors a=4.5m单跨弹性模量：s=500n/mmresulting spring constant of both supports of one span s=500n/mm双分裂导线2*aac-800参数：twin conductor 2 aac-800 分裂数：n=2number of sub-conductors n=2分裂间距：=200mm单导线截面积：as=0.00080209 m2单导线重量：ms=2.218 kg/msub-conductor mass per unit length ms=2.218 kg/m单导线弹性模量：e =5.50e+10 n/m2youngs modulus e =5.50e+10 n/m2单导线外径：ds=0.0368 msub-conductor diameter ds=0.0368 m母线跨静态张力（考虑大风时最严重工况）fst= 10.454 knstatic conductor tensile force (local maximum wind speed) fst= 10.454 kn引下线导线及金具参数：additional concentrated masses representing the connections of pantograph disconnectors引下线数量： nc=2number nc=2引下线设备重量：mc= 30 kgmass of one connection mc= 30 kg引下线距离：ls1=0.4m ;ls2=17.4m;ls3=9.1mdistances ls1=0.4m ;ls2=17.4m;ls3=9.1m重力加速度：gn= 9.81 m/s2conventional value of acceleration of gravity gn= 9.81 m/s21.2 短路时三相导线电磁力及特性参数计算1.3 electromagnetic force and characteristic parameters1）三相导线电磁力：f=20.75*i2a*lcl=42*0.75*31.5*31.54.5*26.933.8*10-1=26.3n/mthe electromagnetic force per unit length is 对应iec_60865-1公式19（考虑金具附加重）导线重量：msc=ms+nc*mcn*lc=2.218+2*30/2*26.9=3.33 kg/mthe resulting mass per unit length of one sub-conductor is msc=ms+nc*mcn*lc=2.218+2*30/2*26.9=3.33 kg/m参数r=fgn*n*msc=26.3/9.8*2*3.33=0.402the parameter r is r=fgn*n*msc=26.3/9.8*2*3.33=0.4022）电磁力作用下导线偏角2）the direction of the resulting force is 电磁力作用下中相导线等效静态弧垂： the equivalent static conductor sag at mid span is 3）导线震荡时间：1.69s3）the periods of the conductor oscillation are1.69s4）应力计算4）stress calculation因because 则根据iec_60865-1公式26得出以下参数=2.43* n/m2so =2.43* n/m2应力计算结果如下：1/nthe stiffness norm is1/n应力系数：2.09the stress factor is2.09因0.5because 0.5则根据iec_60865-1公式29得出应力摇摆角：the span swing-out angle is 则根据iec_60865-1公式30，31得出短路时最大摇摆角：the maximum swing-out angle is 1.3 短路状态下导线拉伸力计算1.3 tensile force during the short circuit因because 则根据iec_60865-1公式32得出负载参数：=0.23the load parameter is =0.23根据iec_60865-1附图表格7如下：可得出参数=0.78according to figure 7 of iec_60865-1, the factor =0.78短路状态下导线拉伸力：the tensile force during the short circuit is 1.4 短路后导线下落时拉伸力计算1.4 tensile force after the short circuit因参数r=0.4020.6，并且短路时最大摇摆角，此工况下不需验算导线下落时的拉伸力。because r=0.4020.6, and during the short circuit, so the tensile force after the short circuit is not significant.1.5 短路工况导线摇摆安全距离校验1.5 horizontal span displacement and minimum air clearance弹性膨胀系数：the elastic expansion is 热膨胀系数：the thermal expansion因because 则根据iec_60865-1公式37得出热膨胀系数：so the thermal expansion is 参数1.07the factor 根据iec_60865-1公式39知according to formula 39 of iec_60865-1导线短路摇摆风偏距离：the maximum horizontal span displacement is 导线短路摇摆时导线间最小安全距离： the minimum air clearance is 从结果知满足安全距离要求。from the result we know that the distance is suited.1.6 次导线张力计算1.6 pinch force参数v1计算如下：factor v1 is根据iec_60865-1附图表格8如下：according to figure 8 of iec_60865-1可得出参数=1.83factor =1.83根据iec_60865-1附图表格9如下：according to figure 9 of iec_60865-1可得出参数=0.34factor =0.34次导线短路电动力计算：mthe calculation of short-circuit current force:m应变因数：the strain factors are:根据iec_60865-1附图表格10如下：according to figure 10 of iec_60865-1，时可得出参数=4.07when ，factor =4.07次导线张力计算结果：the result of the pinch force is 1.7 短路动态张力计算结论1.7 conclusions根据以上计算结果知：according to the calculation we know:短路状态下导线拉伸力：tensile force during the short circuit 短路状态下次导线张力：pinch force during the short circuit 以上两者取最大值校验如下：the maximum value of them shall be applied to check:短路状态下次导线张力：aac-800的破坏荷载=128kn。the tensile force during the short circuit the load of aac-800=128kn因此短路状态下导线不会发生破坏拉断现象。so the line will not break during the short circuit.另外根据iec_60865-1 中2.4.1节对连接导线绝缘子串及架构机械应力验算：according to 2.4.1 of iec_60865-1取及中的最大者校验连接导线绝缘子串及架构机械应力choosing the maximum of and to check the stress from the insulators and connect