电网脆弱环节辨识及其预警方法研究

发布时间：2018-05-05 11:19

本文选题：电网脆弱性 + 奇异值熵　；参考：《华北电力大学》2017年硕士论文

【摘要】：电网脆弱性描述了系统在正常运行时,所能够承受干扰或故障的能力,以及不能够维持正常运行的可能趋势。对电网脆弱环节的辨识和脆弱性的评估,有助于把握电网脆弱性随系统运行变化的规律,对预防连锁故障具有重要意义。首先,从熵理论角度出发,综合考虑奇异值熵和潮流分布熵,提出了节点综合评估指标。奇异值熵表征了节点负荷变化对系统中节点电压幅值的影响,潮流分布熵体现了节点负荷变化对系统中线路潮流分布的影响。定义的节点综合评估指标从电气学的角度解释了节点负荷变化对系统带来的威胁。基于系统平均负载率和能量熵定义了系统安全指标,通过对节点的连续攻击分析评估模型的有效性和正确性。以IEEE 39节点系统和河北南网系统为仿真算例,验证了方法的有效性。然后,为了辨识引发电力系统连锁故障的脆弱线路,从事故发展的角度出发,基于自组织临界理论的幂律特性构建了电网脆弱线路辨识模型。线路因保护的隐藏故障或过载而退出运行后,利用孤岛搜索辨识引发系统解列的关键线路,然后综合改进的潮流分布熵、灵敏度分析理论和OPF模型调整负荷水平和发电机出力,构成了电网停电模拟模型。通过大量的仿真与统计,利用系统负荷损失量的幂律或幂率尾特性判断系统是否达到临界状态。以IEEE 39节点系统为仿真算例,验证了方法的正确性和有效性。最后,综合考虑系统潮流分布、系统电压稳定性以及电网拓扑特性等因素构建了电网脆弱性安全预警模型。最小奇异值可定量表示系统电压与电压静稳临界点的距离,表征节点电压稳定状态;改进潮流熵综合了网架结构完整度和系统平均负载率,提高了信息熵表征电网潮流分布的准确性;最小奇异值灵敏度熵反映了系统所面临负荷冲击的风险。综合以上因素利用犹豫模糊决策方法综合评估系统的脆弱节点。仿真算例评估了IEEE 39节点系统和河北南网实际系统的脆弱性,验证了模型的有效性。
[Abstract]:Power grid vulnerability describes the ability of the system to withstand disturbances or failures when it is in normal operation, as well as the possible trend that it cannot maintain its normal operation. The identification and assessment of the vulnerability of power grid is helpful to grasp the law of the vulnerability changing with the operation of the system, and it is of great significance to prevent the cascading faults. Firstly, from the point of view of entropy theory, considering the entropy of singular value and the entropy of power flow distribution, a comprehensive evaluation index of nodes is proposed. The singular value entropy represents the effect of node load change on the voltage amplitude in the system, and the entropy of power flow distribution reflects the influence of node load change on the line power flow distribution in the system. The defined comprehensive evaluation index explains the threat to the system caused by the change of node load from the point of view of electrical science. Based on the system average load rate and energy entropy, the system security index is defined, and the validity and correctness of the model are evaluated by analyzing the continuous attack on nodes. The effectiveness of the method is verified by the simulation examples of IEEE 39 bus system and Hebei South Network system. Then, in order to identify the weak lines that cause cascading faults in power system, a power law model based on self-organizing criticality theory is constructed from the view of accident development. After the line is out of operation because of hidden fault or overload of protection, the key lines causing system unwinding are identified by islanding search, and then the improved power flow distribution entropy, sensitivity analysis theory and OPF model are used to adjust the load level and generator output. The simulation model of power outage is constructed. Through a large number of simulations and statistics, the power law or power rate tail characteristic of the system load loss is used to determine whether the system reaches the critical state or not. The IEEE 39 bus system is taken as a simulation example to verify the correctness and effectiveness of the method. Finally, considering the system power flow distribution, system voltage stability and network topology characteristics, a vulnerability security early warning model is built. The minimum singular value can quantitatively represent the distance between the voltage and the critical point of voltage static stability, and represent the voltage stability of the node, and the improved power flow entropy integrates the integrity of the grid structure and the average load rate of the system. The accuracy of information entropy for power flow distribution is improved, and the minimum singular value sensitivity entropy reflects the risk of load shock. Based on the above factors, the fragile nodes of the system are evaluated by the method of hesitating fuzzy decision. A simulation example is given to evaluate the vulnerability of the IEEE 39 bus system and the real system of Hebei South Network, and the validity of the model is verified.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM711

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