Initialization Method of Electromagnetic Transient Simulation for AC-DC Hybrid Power System Based on Three-Phase Power Flow

It takes a long time for the uninitialized electromagnetic transient simulation to reach the steady-state operation point, and even the divergence of numerical calculation will be caused by the distance between the initial point and the steady-state point. The three-phase imbalance of the AC-DC hybrid power grid cannot be ignored. The three-phase fundamental power flow can effectively improve the electromagnetic transient simulation speed of the AC-DC hybrid power grid. Under the three-phase unbalanced condition, the analytical expression of impedance, harmonic and control characteristics of the active distribution network with new energy resources is very complex, and the feasibility of engineering calculation is low. Therefore, the artificial neural network is used to fit its complex impedance, harmonic and control characteristics, and then it is nested into the three-phase fundamental power flow calculation framework based on the improved node method to modify the power of the new energy resources in the iterative process. In order to adapt to the initialization of large-scale active distribution network, a parallel calculation method based on Multi-Area Thevenin Equivalent (MATE) parallel computing method is proposed to improve the calculation efficiency of three-phase fundamental power flow. The effectiveness of the proposed method is verified by the three-phase unbalanced AC-DC hybrid power grid including photovoltaic power station(PV) with ieee33 node and 330 nodes.