伴随着经济的快速发展，电力需求增长迅速，电网互联规模不断扩大，电网复杂程度急剧增加，发生大停电事故的风险也随之增加。连锁故障是一种可以引发大停电的严重故障，研究连锁故障的传播机理并对其进行预防阻断，将有效提高电力系统安全稳定水平。为此，论文在深入研究电力系统运行可靠性理论的基础之上，开展了元件实时停运率建模、连锁故障传播过程分析、连锁故障评估算法和连锁故障的预防及阻断对策研究。在元件实时停运率建模方面，提出了改进的证据理论，以便考虑不同停运因素间的相关性及关键因素影响，结合实测数据量化元件自身健康状况、外部环境和运行状态三类停运因素共同作用下的元件实时停运率。该模型结合实测数据，完善了元件老化停运、偶然停运和保护动作导致停运的实时停运率模型，并应用改进的证据理论综合主观判断和客观数据对三类停运率模型进行合成。合成后的元件实时停运率模型可以发现系统在当前运行条件下的潜在故障元件，并在连锁故障传播过程中分析外部环境导致的元件非关联性故障风险。在连锁故障传播过程分析方面，为了考虑跨电压等级间的潮流转移问题并分析元件故障间的相关性，论文在全电力系统范围内研究了继电保护装置的隐性故障、断路器的共模关联故障特性以及备用电源自动投入动作对连锁故障传播的影响，建立了变电站等效模型，实现了跨越多个电压等级、多个层次的全电力系统故障评估，可在连锁故障传播过程中找到后继的故障事件。在连锁故障评估算法方面，给出考虑潮流转移造成的关联性故障与外部环境导致的非关联性故障的连锁故障传播机理，提出了基于马尔可夫过程的连锁故障快速搜索算法。算法考虑了元件故障顺序对系统负荷损失的影响，提出了扩展系统状态空间及采用相关元件停运率计算连锁故障状态转移概率的方法，解决了连锁故障马尔可夫过程的求解难题。在此基础上，针对连锁故障不同发展阶段的关键停运因素提出了减小搜索空间的方法，实现了对连锁故障全面的、快速的搜索。在连锁故障的预防及阻断方面，量化了连锁故障风险，在规划阶段，结合元件关键性及相关性分析，找到了系统薄弱环节并进行升级改造；在运行阶段，结合连锁故障风险评估结果，提出了分阶段预警方案，并结合不同初始扰动事件下的连锁故障事件树及关键路径分析，考虑了元件故障间的相关性，提出了基于连锁故障事件树的预防及阻断对策，实现对连锁故障的防御。

With the rapid economic development, the demand for electricity is growing rapidly and the power grid interconnection is expanding. Meanwhile, the complexity of the power grid increases sharply, blackouts risk also increases. Blackouts caused by cascading outages is a major threat to the power system. Therefore, it is very necessary to analyze the cascading outage so that to improve the level of power system security and stability. Based on the depth study of the power system operational reliability theory, this thesis carries out the research of the real-time outage rate modeling, the cascading outage propagating analysis, the cascading outage evaluation algorithm, the cascading outage prevention and blocking countermeasures.In the real-time outage rate modeling of the electrical component, the improved evidence theory is proposed to obtain the real-time outage rate integrating various outage factors. Combined with the real-time power system operating information, the weather forecast information, the on-line monitoring information and the geographical information, this thesis presents several outage rate models considering the aging process, occasional outages and protection devices’ operation when the components is working abnormally. Then the correlations between the various outage factors and critical outage factor is analyzed, an integrated outage rate model is given considering the subjective judgement and objective data based on the improved evidence theory. This outage rate model could be used to discover the potential outage components in the current operating condition and to find out the independent outages during the propagating of the cascading outages.In the cascading outage propagating analysis, to analyze the relationship between outages during a cascading outage, the problem of cross-flow transferring between voltage levels is considered, then the influence of the delay’s common failures, hidden failures and backup power supply’s automotive operation on the cascading outages’ propagating are analyzed in the over-all power system, an equivalent model of the substation is established. With this model, the reliability assessment could evaluate multi voltage levels and hierarchies all together, it could be used to locate the subsequent outages in the propagating of the cascading outage.In the cascading outage evaluation algorithm, this thesis proposes a cascading outage mechanism in which the dependent outages caused by power flow transferring and independent outages caused by external environment are both considered to simulate a cascading outage event, then a cascading outage fast searching algorithm based on Markov process is proposed. The algorithm considers the influence of outage sequences on the load curtailment, and to tackle the solving problem of Markov process, the method of expanded system state space is given and the method of using relevant components’ outage rate to calculate system states’ transition probability is proposed. Furthermore, the critical factors at different stages of the cascading outage evolution are analyzed, then a method of reducing the searching space is given, it accomplishes the comprehensive and fast searching of cascading outages.In the cascading outage prevention and blocking countermeasures, this thesis proposes a series of blocking countermeasures for cascading outages based on the analysis of the outage tree. The risk indices are proposed and in the planning phase, the critical components and correlations between different outages are quantified, then the upgrade program is presented. In operating phase, combined with the cascading outage on-line forecast results, the early warning program at different time scales is presented, furthermore, a prevention strategy under a particular initial disturbance and its event tree is presented considering the correlations between outages. From the upgrade of vulnerable parts in planning to the prevention blocking in operating, the defense for the cascading outage in the whole process of electricity production is achieved.