Is there a way to identify excel files that are protected.

There is a field called "Has Object Hidden". This flag is set to 'Yes' if the excel files are protected or macros are enabled in those files.

We can also find  a field called 'HasMacrosAndCode' field in tbl_ex_edocmeta table in the respective project database. This flag is set to 1 if a files has macros enabled in it.