If an import mode dataset is hosted in an App Workspace assigned to Power BI Premium capacity, up to 48 refreshes can be scheduled per day. Additionally, an incremental refresh will be available to datasets in Power BI Premium workspaces, such that only changed or new data will be loaded to the Power BI Service. If the dataset is in a shared capacity workspace, a max of eight refreshes per day can be scheduled and the entire dataset must be refreshed (incremental refresh will not be available).
Currently scheduled refreshes must be separated by a minimum of 30 minutes.