文档介绍：华北电力大学(保定)
硕士学位论文
配网架空线雷电感应过电压计算及闪络概率研究
姓名:翟绍思
申请学位级别:硕士
专业:电气工程
指导教师:梁贵书;靳伟
2011-06
华北电力大学硕士学位论文
摘要
雷电感应过电压是配网线路发生绝缘闪络的主要原因,其降低了供电
可靠性,给人们生产与生活带来了严重影响,因此,实现雷电感应过电压
的计算、预测架空线路的闪络概率并对雷电感应过电压防护措施进行研究
具有重要的工程价值和实际意义。
本文首先介绍了雷电感应过电压的产生机理,雷电感应过电压对输电线路
的耐压水平等的重要性,并对雷电回击模型进行了阐述和总结。本文将雷电视
为垂直于大地表面的电流通道,基于电磁场理论,利用雷电感应电磁场的近似
计算公式,完成了考虑有损大地情况下的雷电感应电磁场的求解;并以所求电
磁场为激励,结合 Agrawal 场线耦合模型,基于时域有限差分法(Finite
Difference Time Domain, FDTD)推导了改进电报方程的时域递推差分形式,编
写相应的计算程序,实现了配网架空线路的雷电感应过电压计算。通过对一段
典型架空线路进行计算并与现有文献结果比较,验证了程序的正确性。
利用所编写的计算程序,讨论了大地电阻率对雷电感应过电压的影响,得到
了在雷电感应过电压计算中必须计及大地损耗的结论。此外,还探讨了配网线路
雷电感应过电压闪络概率的计算方法,并讨论了避雷线的架设对线路闪络概率的
影响,说明了在线路上方架设避雷线不仅可以减少直击雷害而且还可以有效降低
感应雷导致的线路闪络,提高供电可靠性。
关键词:配网架空线;雷电感应过电压;时域有限差分法;闪络概率
I
华北电力大学硕士学位论文
Abstract
LIGHTNING induced overvoltages may cause damage to the insulation of the
distribution lines or other power equipments. Erksson et al. have evidenced that the
indirect lightning return strokes, hitting the ground in the vicinity of overhead lines,
constitute a more dangerous cause of damage than direct strikes, because of their
more frequent occurrence. The research on the calculation of the lightning-induced
overvoltages and prediction of the flashover of the distribution power system are very
important for the insulation design of power lines.
This paper introduces the mechanism of the lightning over-voltage, the
importance of lightning induced over-voltage for the voltage level of the distribution
overhead line. It assumes that the shape and speed of the lightning current remain the
same with height while the amplitude is exponentially decay with the height. As the
disadvantage of having a discontinuity at the stroke tip, which is presented in other
models, is avoided. The Heidler model is chosen as the lighting base current model.
Assuming the lightning channel as a vertical channel to the ground, the
ic is calculated based on the Maxwell equation. The Agrawal model is
ch