天然气管网系统的稳态安全域模型

Steady-state security region model of the natural gas transmission system

参考电力系统的安全域概念,提出了天然气管网系统安全域(NGS-SR)的稳态模型、可视化与应用方法。NGS-SR能描述系统全部的安全状态;传统稳态仿真分析只能判断单个状态的安全性。对NGS-SR进行了定义:NGS-SR为系统运行时,所有安全工作点构成的集合;建立了NGS-SR的稳态模型,模型充分考虑了管道压降、节点流量与压力约束等安全要素。提出了NGS-SR安全边界的定义与模型;安全边界是NGS-SR中所有临界安全工作点的集合,NGS-SR是由安全边界围成的封闭区域。通过观测工作点的安全分界现象以说明安全边界的存在,并提出了NGS-SR的观测方法。提出了NGS-SR安全距离的概念与计算方法,对基于NGS-SR安全距离的安全性评估和安全控制进行了说明,简述了如何利用NGS-SR指导系统运行。算例验证了NGS-SR的存在性以及所建立模型与方法的正确性,并与传统安全分析方法进行了对比。NGS-SR描述了天然气管网系统的安全运行范围,可提供丰富的安全控制信息,有助于实现在线安全分析。

The steady-state model, visualization method and application of the security region of natural gas transmission system(NGS-SR)are proposed in this study. NGS-SR can describe all the secure states of the system, while the traditional stead-state simulation can only estimate the security of single state each time. First, NGS-SR is defined as being the set of all secure operating points during system operation. Second, the steady-state model of NGS-SR has been established when fully considering the security factors such as pressure drop of pipe, node flow and pressure constraints. The security boundary is defined as the set of all critical operating points in NGS-SR, and NGS-SR is a closed area surrounded by the security boundary;the model of NGS-SR is also proposed. Third, the dividing phenomenon of the operating points is observed to indicate the existence of security boundary, and the observation method of NGS-SR is also proposed. Forth, this paper puts forwards the concept and calculation method of security distance of NGS-SR, illustrates the security assessment and preventive control based on security distance and briefly describes the way of using NGS-SR to guide the system operation. Finally, the existence, model and relevant methods of NGS-SR are verified by cases. NGS-SR describes the secure operation range of natural gas pipeline network system in a visualized way, it can also provide rich information of security control and is beneficial to realize the online security analysis.