Node-Based Steady-State and Dynamic Gas Grid Calculation Method With Electrical Analogies

For joint intelligent and safe operation of electric power and gas grids, network condition estimates and the knowledge of propagating effects are important. For considering these two systems on a common level, this investigation proposes electric equivalents for gas grid components and defines them in the context of the “Extended Node Method”. Hence, it enhances this efficient node-based method, originally for power grids, to also be applied to gas networks. For this, the isothermal Euler equations are interpreted within the electric context. While the steady-state electric equivalent circuit diagram of a gas pipeline mainly consists of an ohmic resistance, the transient flow characteristics also show inductive and capacitive behavior. It is derived, how the network components are classified in terms of their terminal behavior and how this affects the characterization of network nodes and the structure of the equation system. An iterative algorithm for steady gas flow and a straightforward calculation process for unsteady flow are developed based only on node equations. Study cases for sample gas networks of different pressure levels are investigated with varying spatial resolutions of pipeline segments. The steady-state results show very high agreement compared to the established tools Simulink/Simscape and pandapipes and the procedure is computationally efficient. From a number of four segments, the results hardly vary at all. Small deviations are observed for dynamic considerations. These depend on the spatial resolution and are attributed to the electromagnetic effects of the electrical analogies. The computing time for the models increases with higher spatial resolution.