1m级间隙正极性雷电冲击闪络判据海拔校正方法的适用性

Applicability of Altitude Correction of 1 m Level Gap Positive Lightning Impulse Flashover Criterion

绝缘子及空气间隙的雷电冲击闪络判据是评估输电线路耐雷性能的重要仿真模型之一,同一间隙的闪络判据在不同海拔地区应用需要进行海拔校正。绝缘子及空气间隙的雷电冲击U50%闪络判据可以采用g参数进行海拔校正,但是更加精确的闪络判据如伏秒特性及先导发展模型法尚缺乏有效的海拔校正方法。该文针对110kV线路用复合绝缘子及1m棒-板间隙,分别在平原和高海拔地区开展了正极性标准雷电冲击试验,对比了海拔对冲击闪络特性的影响,分析了现有海拔校正方法在U50%及伏秒特性散点校正中存在的问题。然后,拟合了适用于不同海拔的110 kV单支复合绝缘子及1 m棒-板间隙的正极性标准雷电波先导发展模型,并将该模型计算得到的U-t曲线与试验所得的伏秒特性散点进行对比分析,验证了先导发展模型通过改变相对空气密度开展闪络判据海拔校正的适用性。最后,通过对比分析不同先导发展模型对计算110kV输电线路耐雷水平的影响,证明了先导发展模型闪络判据海拔校正的精确性。

The flashover criterion of insulator and air gap is an important simulation model to evaluate the lightning re-sistance performance of transmission lines.The flashover criterion at different altitudes needs altitude correction.The U50%flashover criterion can be corrected by the g parameter,however,the more accurate flashover criterion,namely,us-ing the volt second characteristic and leader propagation model method,still lacks effective altitude correction.Aiming at the composite insulator used in 110 kV line and 1m rod-plate gap,we carried out the positive polarity standard lightning impulse tests in plain and high altitude areas,respectively,compared the influence of altitude on impulse flashover char-acteristics,and analyzed the problems of existing altitude correction methods in U50%and volt-second characteristic scatter correction.Then,a positive standard lightning wave leader propagation model suitable for 110 kV single compo-site insulator and 1m rod-plate gap at different altitudes was fitted,and the U-t curve calculated by the model was compared with the test volt-second characteristic,verifying the applicability of the leader propagation model to carry out the altitude correction of flashover criterion by changing the relative air density.Finally,by comparing and analyzing the effects of different leader propagation models on calculating the lightning withstand level of 110 kV transmission lines,the accuracy of altitude correction of flashover criterion of leader propagation model is verified.