中文摘要：

提出了一种考虑备用输电元件对发输电系统可靠性影响的评估方法。该方法对备用元件分2种情况进行分析：对于备用元件的投入或退出不改变系统网架结构的情况,计及备用元件投切时间,提出了一种7状态元件可靠性模型;对于备用元件的投入或退出改变系统网架结构的情况,采用补偿法模拟不同网络元件的开断或投入对系统网架的影响。文中采用序贯蒙特卡洛模拟法对含备用元件的系统进行模拟,实际系统算例显示,考虑备用输电元件后,系统可靠性有了一定程度的提高,系统可靠性指标——电量不足期望（EENS）平均偏离程度减小。利用文中所提出的方法进行可靠性评估,其结果更接近实际情况,可以更准确地找到系统薄弱环节,为电力系统运行和规划提供重要的参考。

英文摘要：

An evaluation method for considering the influence of standby transmission components on the transmission system reliability is presented.Two typical cases for analyzing the standby transmission components are considered.For the cases that the system network structure is not changed by the switching of standby components,a seven-state reliability model considering the switching time of standby components is presented.For the cases that the system network structure is changed by the switching of standby components,the compensation method is used to simulate the influence of the standby components＇ switching on the system grid.Sequential Monte Carlo simulation is used to simulate systems with standby components.The practical calculation example shows that the system reliability is improved to a certain degree,and the average deviation of system reliability indicator,i.e.expected energy not supplied（EENS）,is reduced.While using the method presented,the evaluation results of the system reliability is closer to the actual situation,and the weak links of the system can be found more accurately,thus provide an important reference to the operation and planning of power systems.