Here the procedure to import or export ComTrade

Export:
Open Result file. Press Button Export, select "Export to": Comtrade.
This means that, if you want to export to comtrade you can write the data to be exported into a result file, and then follow the procedure given.

Import:

Create an object of type "ElmFile". Select "Import From": Comtrade. Select the comtrade file.

Press F1 to see how the signals from the Comtrade file can be connected to other block definitions.

For transient simulation you have to create and use a block definition with the ElmFile, not necessarily connected to other blocks, in order to be able to select the signals in a result file, which then can be used to view the curves.