From Power BI Connector version 1.3.0, the possibility to export expanded Reference fields was added. It is possible Export of Reference fields gives the ability to get not only the direct parent-field, but go deeply into tables table dependencies and select the child-fields, that you need.
Navigate to Data Source page (or create a new one). Add a table, and if it contains Reference type fields, the “+“ will be shown near it.
...
Child-fields can also be a Reference type(highlighted by green color) and contains contain their child -fields. Which table is used as a reference can be checked on the backend side.
...
3. Select the necessary field, by clicking on it once. If need to go deeply into tables, click on “+” icon near the field. Selected fields will be added in the Selected column.
...
After the field is added, check its path and change Display value setting if needed.
...
5. Save Data source, copy OData URL and export it in Power BI the Tableau desktop.
New child-fields can be found as additional columns in a selected table. Data will be shown according to Display settings for each table.
...
NOTE: Dependent on user permissions for tables, there are the different list lists of fields that will be able to select on the data source page.
...