IEEE Power Electronics Magazine, 4(2):56-67, 6, 2017. Paper Website abstract bibtex
The solid-state transformer (SST) was con- ceived as a replacement for the conventional power transformer, with both lower volume and weight. The smart transformer (ST) is an SST that provides ancillary services to the distribution and transmission grids to optimize their per- formance. Hence, the focus shifts from hardware advan- tages to functionalities. One of the most desired func- tionalities is the dc connectivity to enable a hybrid distri- bution system. For this reason, the ST architecture shall be composed of at least two power stages. The standard design procedure for this kind of system is to design each power stage for the maximum load. However, this design approach might limit additional services, like the reactive power compensation on the medium voltage (MV) side, and it does not consider the load regulation capability of the ST on the low voltage (LV) side. If the SST is tailored to the services that it shall provide, differ- ent stages will have different designs, so that the ST is no longer a mere application of the SST but an entirely new subject.