A Study on Average Models of DC/DC Converters for Fault Response Analysis of MVDC Distribution System Using EMT Simulation

To reduce carbon emmisions, the proportion of DC-based renewable energy sources has been steadily increasing in recent years. Consequently, extensive research is being conducted on the conversion of parts of MVAC distribution systems to MVDC. In DC distribution systems, power-electronic-based DC/DC converters serve the role of traditional transformers in AC systems. In studies on protection strategies of DC power systems, multiple converters must be modeled within a single test system using EMT simulation. However, modeling multiple converters in detail increases the computational burden of the EMT simulation substantially, creating a major bottleneck in research progress. This paper analyzes the average models of various DC/DC converter topologies applicable to MVDC systems. These average models can adequately reflect the fault response characteristics necessary for developing protection strategies in MVDC distribution systems. The EMT simulation and analysis were conducted using MATLAB/Simulink software.