基于结构平衡理论的电网自组织临界态辨识

Self-Organized Critical State Identification of Power Systems Based on Structural Equilibrium Theory

准确度量复杂电网自组织临界态对于电力系统连锁故障的预防控制以及电网的升级改造均具有重要的应用价值。该文将电网输电线路虚拟为节点,以输电线路间的相互关联作用为边,综合考虑线路初始负载率、负载率增量和负载率增量的平均值定义了输电线路间相互影响的符号属性,进而构建了以线路重要度为点权、以线路间相互影响的符号属性为边权的电力系统状态关联网络。借鉴一般符号网络的结构平衡理论,建立并分析了电力系统运行状态平衡结构的模式及分类。在此基础上,提出了电力网络不平衡度的综合评价指标,该指标既可表征线路间潮流分布特性,又可表征能量化系统的扰动化解能力,可用于度量系统的自组织临界态。仿真结果表明,网络不平衡度在不同网架结构、潮流熵和负荷水平下均能有效识别电网自组织临界态,特别是在低负荷、低潮流熵工况下,仍有较强的适应性。

Self-organized critical state identification has the important value for preventive control of cascading failures and power network planning.First,the transmission lines are represented as virtual nodes and the power flow interactive relations between the transmission lines as virtual links.Synthesizing the initial load rate,load rate increment and average of load rate increment,this paper defines the sign properties of the virtual links and then constructs a state correlation networks where importance degree of lines is used as node weight and the link sign properties as link weight.Based on the structural equilibrium theory of signed networks,the balance structure pattern and classification of power system operating states is established and analyzed.On this basis,a comprehensive of power network imbalance evaluation index is proposed to represent the power flow distribution characteristic and quantify power system disturbance dissolving ability,which can identify the self-organized criticality of a power system.Numerical results indicate that the defined imbalance index can effectively indicate the self-organized criticality of a power system in different network topologies,load rates and power flow entropy,and especially it works well when the system load rate and power flow entropy is lower.