A Steady State Model of Solid-State Transformer for a Sequential AC–DC Power Flow in AC–DC Power Grids

This article presents, for the first time, the steady-state analysis of composite ac–dc grids embedded with solid-state transformers (SSTs) taking into account the high-frequency transformers in the dc–dc converters of the SSTs. A novel steady-state model of the SST is presented in this article, which includes loss calculations, and facilitates steady-state and impact analysis without complex and time-consuming time-domain simulation. The new steady-state model of the SST proposed in this article was validated using the time domain simulation of the detailed model in a two-bus topology on the MATLAB/Simulink platform. Subsequently, the proposed approach has been implemented in two additional case studies to validate its enhanced performance when utilizing SSTs and demonstrate how the proposed model can be employed for steady-state analysis of the modern grids that encompass a diverse range of converter-interfaced renewable energy generation sources, as well as the system that contains both ac and dc loads.