中文摘要：

敏感负荷电压凹陷敏感度评估的关键在于电压耐受曲线随机分布规律的确定。文章以勒让德多项式为基函数，提出一种通过最佳平方逼近法确定敏感负荷电压凹陷敏感度特征参数随机分布的概率密度函数的方法，该方法无需主观假设，忠实于样本特征，具有原理简单、计算量小的特点。文中对概率密度函数的逼近算法、评估原理和过程进行了研究，以PC机为例，通过蒙特卡罗方法随机模拟样本，用所提出的方法进行评估，证明了所提出方法的准确性和适应性。

英文摘要：

The key of voltage sag sensitivity assessment of sensitive equipments consists in the determination of random distribution regularity of voltage tolerate curve. Serving Legendre polynomial as basis function, a method to determine probability density function of characteristic parameter stochastic distribution of voltage sag sensitivity of sensitive equipments by optimal square approximation is proposed. Needing not subjective assumption and being faithful to sample characteristic, the principle of the proposed method is simple and its calculation burden is light. In this paper the approximation algorithm of probability density function and the assessment principle are researched. Taking personal computer （PC） for example and using Monte Carlo stochastic simulation samples, the voltage sag sensitivity of PC is assessed by the proposed method. Assessment results show that the proposed method is accurate and adaptable.