Dynamic analysis of SNG and PNG supply: The stability and robustness view

The methods of robust analysis and stability analysis of natural gas supply system are proposed. Using this method, the integration of bifurcation theory and Lyapunov's stability theory was performed, accounting for uncertainty and complexity. China's natural gas supply system is composed synthetic natural (SNG) and pipeline natural gas (PNG), both of which change unsteadily and interact in a nonlinear manner, making the supply process of the natural gas supply system dynamic. In light of this, and based on the Two Species Competition Model, a natural gas supply dynamics model composed of SNG and PNG is established to express the dynamics of China's natural gas supply system. Fixed points stability analysis theorems are proposed with reference to Lyapunov's stability theory, and the stability of the natural gas supply process was analyzed using these theorems, whose rationality was verified by numerical simulation. The robustness of the natural gas supply system is described in detail in terms of the external disturbance degree and the inherent invulnerability of the system, by means of bifurcation theory and the maximum Lyapunov exponent. •The stability of fixed points are determined by system parameters.•The output values of natural gas are constant in the state of stable fixed point.•The output values are uncertain in the state of unstable fixed point.•The robustness of the natural gas supply system is affected by disturbance type.•By optimizing system parameters, the robustness of the system can be improved.