考虑天然气网影响的电网脆弱线路辨识

Identification of Vulnerable Lines in Power Grid Considering Impact of Natural Gas Network

脆弱线路辨识是电力系统运行风险控制的重要环节。在电网-天然气网耦合背景下,天然气网的运行状态对电网运行影响深刻,因此提出一种考虑天然气网影响的电网脆弱线路辨识方法。首先,构建电网-天然气网耦合系统优化模型,求解得到系统初始运行状态。在此基础上,基于熵理论,建立线路耦合脆弱度因子,用于反映天然气网气源故障对电网线路脆弱性造成的影响。然后,基于复杂网络理论,建立线路结构脆弱度因子和运行脆弱度因子,从结构性视角和运行状态2个方面揭示电网固有的脆弱性。综合上述脆弱度因子,得到用于辨识电网脆弱线路的综合脆弱度指标。采用网络效能和系统输电效率2个指标反映线路故障对电网的影响,验证所辨识出的脆弱线路。由IEEE 30节点系统和比利时20节点天然气系统组成的电网-天然气网耦合测试系统算例表明,所提方法能够有效地分析天然气网对电网脆弱线路辨识造成的影响。

Identification of vulnerable line is an important part of risk control for power system operation. Under the background of power grid and natural gas network coupling, the operation state of natural gas network has a profound impact on the operation of power system. This paper presents a method for identifying the vulnerable lines of power grid considering the impact of natural gas network. Firstly, the steady-state optimization model of power grid and natural gas network coupling system is constructed, and the initial operation state of the coupling system is obtained. Based on the entropy theory, the coupling vulnerability factor is established to reflect the impact of gas source failure on the vulnerability of lines of power grid. Based on the complex network theory, the line structure vulnerability factor and operation vulnerability factor are established to reveal the inherent vulnerability of power grid from the structural perspective and operation status. Based on the above vulnerability factors, a comprehensive vulnerability index for identifying vulnerable lines is obtained. Then, two indicators of network efficiency and system transmission efficiency are used to reflect the impact of line faults on power grid to verify the identified vulnerable lines. Finally, a case composed by the IEEE 30-bus system and a 20-bus Belgian gas network shows that the proposed method can effectively analyze the influence of natural gas network on the identification of vulnerable lines in power grid.