蒙特卡洛法在风电场架空输电线路绕击跳闸率计算中的应用

Shielding Failure Trip-out Rate of Overhead Transmission Line of Wind Farm Calculated by Monte Carlo Method

雷电绕击导致的风电场线路跳闸事故严重影响风电场的安全运行,为此,采用蒙特卡洛法编制输电线路绕击跳闸率的仿真计算程序。运用蒙特卡洛法进行仿真时,通过计算获取雷电流幅值、先导入射角、雷电通道坐标、线路电压瞬时值等关键参数,各参数满足对应的概率密度分布;根据改进电气几何模型和输电线路绕击等值电路,来判断雷击部位以及是否发生闪络;最后通过大量仿真计算,统计出输电线路的绕击跳闸率。算例对比表明,在输电线路绕击跳闸率计算中,基于改进电气几何模型闪络判据的蒙特卡洛法比传统的电气几何模型更符合实际情况,计算结果有助于改善输电线路绝缘设计,提高线路防雷水平。

Line tripping caused by lightning shielding failure severely affects safe operation of the wind farm.In for the shielding failure trip-out rate of the transmission line.By using the Monte Carlo method,it carries out the simulating calculation and obtains the key parameters such as lightning current amplitude,the leading angle of lightning incidence,the lightning current channel coordinates,the instantaneous value of line voltage,and so on,each of which satisfies the corresponding probability density distribution.According to the improved electrical geometrical model(EGM)and the equivalent circuit of line shielding failure,the paper could judge whether there is the flashover in the lightning stroke part.Finally,it calculates out the shielding failure trip-out rate of the transmission line by means of a large number of simulation.Examples prove that the failure trip out rate of the transmission line calculated by the Monte Carlo method which based on the EGM of flashover criterion is more in accordance with the actual situation.The calculation results are conductive to improve the design of transmission line insulation and lightning protection level of the line.