A Dynamic Power Flow Calculation Method for the “Renewable Energy–Power Grid–Transportation Network” Coupling System

To address the issue of inaccurate power flow calculations in the asymmetric coupling system of a power grid and traction network, this paper proposes a dynamic power flow calculation method for the “renewable energy–power grid–transportation network” asymmetric coupled system. First, by utilizing the asymmetric characteristics of the traction transformer, the dynamic asymmetric nodal admittance matrix for the “renewable energy–power grid–transportation network” coupled system is established, which facilitates the construction of the mixed power flow equations for the coupling of the power grid and transportation network. Next, when analyzing the asymmetric coupling system of renewable energy, power grid, and transportation network in mountainous areas, it is necessary to allocate the power of electric multiple units (EMUs) to the three-phase (A, B, C) power distribution. To address this, a three-phase power balancing strategy is proposed, incorporating both the single-phase loads of EMUs and the output of renewable energy sources. Thus, a three-phase power balance strategy is proposed, incorporating the single-phase load of traction load units and renewable energy output. Finally, a simulation study is conducted using a real system of a regional power grid and traction network as a case example, demonstrating the suitability and effectiveness of the proposed model.