基于蒙特卡罗法的超高压输电线路绕击跳闸率的计算

Calculation for shielding failure trip-out rate of EHV transmission line based on monte carlo method

为准确评价超高压输电线路的耐雷性能,采用蒙特卡罗法对雷电绕击线路的随机过程进行模拟和统计计算,并通过改进的电气几何模型(EGM)进行绕击的判定。用简化的集总参数模型(级联的π型电路)对线路进行建模,用梯形积分法求解状态空间方程进而计算线路雷电绕击过电压,并与电磁暂态程序(EMTP)计算结果进行了比较,证实了该模型的可靠性。针对一条500 kV超高压线路进行了雷电绕击跳闸率的计算,最后分析了地面倾角,雷电入射角,工频电压对雷电绕击跳闸率的影响。

Accurate evaluation of lightning resistant performance is very important for extra high voltage （EHV） trans- mission line. The shielding failure trip-out rate of EHV transmission lines is studied by using the Monte Carlo method. An improved electro-geometry model （EGM） is used to judge whether the transmission line is shielded or not. The state-space equations based on a simplified lumped-parameter model （ cascade circuits） is solved by the trapezoidal in- tegration, and the lightning over-voltage on the transmission line is calculated, which is compared with those obtained by Electromagnetic Transients Program （EMTP）. The shielding failure trip-out rate （SFTOR） of a 500 kV transmis- sion line is calculated, and the influences of ground obliquity, incidence angle of lightning current and the power fre- quency voltage of the transmission line are also analyzed.