蒙特卡罗法计算线路雷击跳闸率随机过程研究

针对规程法分析输电线路防雷性能中过于简单化和EMTP计算复杂化问题,用较符合雷击实际过程的蒙特卡罗法计算输电线路雷击跳闸率。因雷击随机过程的选取直接影响计算速度和计算结果的确信度,故在研究了雷电流幅值、波头时间、雷击部位、工频电压瞬时值、风偏等随机过程对跳闸率计算的影响的基础上,综合考虑计算速度和计算结果确信度,确定雷电流幅值、雷击部位、反击时工频电压瞬时值为蒙特卡罗法中需要考虑的因素。经验证设计的蒙特卡罗法雷击跳闸率计算结果和实际运行线路雷击跳闸率统计结果相吻合。

Selection of Random Processes in Application of Monte Carlo Method to Calculation of the Lightning Flash-over Rate of Transmission Lines

It is well known that lightening trip out caused by lightening flashover of electrical power transmission lines greatly influences the safety and steady operating of power system.Research has been widely carried out with calculation of lightening flash-over rate of transmission lines.In calculation of lightning flash-over rate of transmission lines,the selection of random processes is very important for the speed and the precision of the calculation.In this paper,the lightening flashover rate of transmission lines is studied by using a modified Monte Carlo method.Typical tower parameters of 110 kV,220 kV and 500 kV transmission lines are selected and the electric geometry method is introduced.The probability of hitting the tower under different kinds of landscape and the shield failure flashover rate under different obliquities are calculated.The back flash-over rate as well as the shield failure flash-over rate of typical towers before and after considering the power frequency voltage is also calculated.The influence of stroke current,front time,the hitting point,transient power frequency voltage and windage yaw on the lightning flash-over rate of transmission line is analyzed.On the basis of analyses above and considering the speed and the precision of the calculation,it is found that the random processes including stroke current,the hitting part and power frequency voltage of back flashover are crucial in the Monte Carlo method.After calculating actual 110 kV,220 kV and 500 kV transmission lines,it is proved on site that this new Monte Carlo method has good correspondence with the real calculating results.