【作者】 王英英；

【导师】 刘沛； 罗毅；

【作者基本信息】 华中科技大学 ， 电力系统及其自动化， 2010， 博士

【摘要】 随着电力系统的大区互联和市场化,电网规模愈发庞大,导致扰动传播的范围也更大,区域电网在一定条件下,可能会受到附近电网故障的影响而发生连锁故障。这种故障往往造成大面积的停电事故甚至电网的彻底崩溃,因此,有效地防止电力系统连锁故障是避免大停电事故的关键。论文首先系统地总结了连锁故障的建模、风险评估和预防控制研究现状,分析了上述研究方法在连锁故障监视和预控方面的不足,提出有必要从理论源头进一步研究连锁故障的实用化分析方法。由于安全科学提出的“事故链”理论将对连锁故障的监控转化为对事故链环节的监控,为连锁故障的监视和预控提供了理论基础,因此,本文从预防大停电事故的角度,采用事故链理论对大停电连锁故障进行建模,并提出了基于供电路径的事故链实用化生成方法。论文引入风险的概念,从系统电压失稳、母线低电压和支路过载三个方面分析了事故链对电力系统安全运行的风险,并建立了详细的风险评估指标。采用模糊综合评估方法对风险指标进行综合和等级划分,得到系统综合风险指标和风险水平,为连锁故障的预防控制决策提供依据。在获得电力系统事故链风险指标和风险水平的基础上,提出了一种降低发生大停电事故的风险、提高系统运行安全性的预防控制方法。该方法通过将控制措施对系统运行的影响以风险指标的形式加以量化,建立了基于风险的优化模型,然后以事故链环节的重要度确定参与决策的关键节点,并采用多种群遗传算法来求取预防控制策略。该方法不仅能够有效地提供最佳的预防控制策略,达到降低发生大停电事故的风险,提高系统运行的安全性的目的,还可以减少不必要的预防控制费用支出。最后,对全文进行了总结并指出了今后有待进一步开展的工作。更多还原

【Abstract】 With the development of the electric power market and the contact of regions, electric power system is extensively distributed and faults are spreading to a large range, some fault in local grid could be extended and transmitted quickly, which may result in cascading failure and then the blackout, even the breakdown of electric power system. So the risk assessment and prevention control for cascading failures is the key to avoid the blackouts.Firstly, the models and risk assessment methods of cascading failures as well as the prevention control researches are systematically summarized in this paper. The defects of above methods on the monitoring and control for cascading failures are also analyzed, it’s a need to go on further research on the practical analysis methods from theoretical source. Therefore, the view of fault chain based on security science is applied to describe and characterize cascading failures, which converts the monitoring on cascading failures into the monitoring on the links of fault chains, thereby provides a theoretical basis for prevention control of cascading failures. Moreover, according to the various influencing factors, the model based on fault chain for cascading failure is set up, and the practical generation method of fault chains based on the power path is studied.Risk assessment taking the probability and the consequence into account is introduced in power system security analysis, and three risk indicators are proposed to indicate the security risk level for prevention control decision making:system voltage instability risk, system low voltage risk and overload risk. Meanwhile, fuzzy comprehensive evaluation method is used to integrate these risk indicators and obtain the comprehensive risk and risk level, and then defensive suggestions are given by analysing the assessment results.Based on the risk indicators, a prevention control method to reduce system risk and improve system security is provided. In this method the influence of control measures on these risk indicators is quantified and the cost of control measures is also converted to the risk. Meanwhile, the control nodes are selected by the importance index of the link in fault chains, and the prevention control measures are determined to meet the requirement that the risk change is the negative maximum value by using the multi-population genetic algorithm. At last, the sum is made and the future work is point out.更多还原