Transient Modeling and Analysis of VSC Based DC Microgrid During Short Circuit Fault

The application of distributed renewable energy (DER) drives the development of DC microgrid based on voltage source converter (VSC). And short circuit fault protection is a significant challenge for the development of VSC based DC microgrid. This paper proposes a transient modeling method for VSC based DC microgrid. Firstly, the transient characteristics of VSC under DC bus voltage control mode and active power control mode are analyzed. And then the faulty DC microgrid model, which consists of VSC model and DC line model, is modeled. And the calculation expressions of state variables in DC microgrid are presented. Next, the correctness of proposed modeling approach is verified by comparing with the electromagnetic transient (EMT) simulation by Matlab/Simulink. Moreover, the case study on the parameters configuration of DC microgrid protection devices shows that the transient modeling method can be effectively used in faulty DC microgrid analysis. The method proposed in this paper can not only ensure the calculation efficiency, but also improve the accuracy of DC microgrid analysis on fault.