Start-up, functionalities and protection issues for CHB-based solid state transformers

Solid State Transformers (SSTs) are envisioned as an alternative to conventional Line Frequency Transformers (LFT) able to meed with the requirements of future power systems. Intensive studies covering SSTs' applications, topologies, functionalities and the performance are in progress. Other relevant aspects to consider are the startup (energization) of the transformer as well as its behavior and potential control strategies in the event of anomalies, e.g. imbalances in the load or even short-circuits. This papers addresses all these issues for CHB-based SSTs.