As S-DMS is a structural model, there are no base types.
The intention of the authors is to develop a model, which would contain all the advantages of both CIM and S-DMS. The most important advantages are the concept of catalogs from S-DMS (bay catalogs first of all) and the clear inheritance hierarchy and curve model of CIM.
Its connectivity, transformer and consumer models are a hybrid of the solutions from CIM and S-DMS. The section model is similar to those from the previous two models.