中文摘要：

针对认知不确定性中的参数不确定性展开详细讨论，推导了期望值风险指标的二阶泰勒级数展开式，可以实现多元件多参数变化后电网期望值风险指标的直接近似解析计算。进一步基于单变量核密度估计理论和随机抽样技术，实现了可靠性参数不确定条件下电网期望值风险指标的概率密度分布计算，为评估可靠性参数随机变化对期望值风险指标的影响提供了更加直观的概率量化分析结果。通过对RBTS和IEEE—RTS79系统的可靠性评估分析，验证了所提出的方法的有效性和正确性。

英文摘要：

The parametric uncertainty is a basic type of epistemic uncertainty in probabilistic power system risk assessment （PRA）. The second order Taylor expansion for PRA index at the mean values of component reliability parameter is derived, through which the expected risk indices can be analytically calculated after multicomponent reliability parameters have been changed. Furthermore, using the kernel density estimation theory and sampling technique, the probability density distributions of expected risk indices under the uncertainty of reliability parameters can be obtained. It provides visual specification of quantitative uncertainty analysis. Finally, the RBTS and IEEE-RTS 79 power systems are used to validate the proposed approach. This work is supported by National Natural Science Foundation of China （No. 50607021, No. 50977094） and Scientific Research Foundation of State Key Laboratory of Power Transmission Equipment and System Security （ No. 2007DA10512709103）.