Double-port network model with fault slag based on multi-terminal DC system

According to the actual requirements of the project, when the pole-to-pole fault occurs in the DC system, the fault must be cleared during the capacitor discharge phase, so the requirements of the calculation of the current transient expression at the fault point are made. To solve this problem, this study proposes a dual-port network model with fault flags. First, analyse the equivalent circuit diagram of the tree and ring DC system after fault, and compare it with the dual-port network model. The relationship between the parameters of the original system and the parameters of the proposed model is given. Second, put the relationship expression into the short-circuit current expression of the dual-port network model and obtain the final transient expression for multi-ended systems. Finally, the 3-end tree and ring DC system model are set up on the MATLAB/Simulink software platform. The simulation of the model is verified. The error is below 5%, which proves the reliability of the model.