Google Drive can convert common Office formatted documents into the Google Doc equivalent when uploading to Drive. For example, an Excel file can be converted into a Google Sheet.
Protection settings on Excel files can not convert into Google Sheets when uploaded and converted. If you wish to upload an Excel file and keep it in Excel format with protection settings intact, you will need to disable the convert uploads setting in Google Drive.
The steps to do this will be different between the old and new Google Drive views.
For the new Drive view:
1. Open up your online Google Drive. Click on the gear icon in the top right corner. In the drop down menu click on Settings.
2. In the Settings menu under the General section, uncheck the check box for the Convert uploaded files to Google Docs editor format setting and click Done.
For the old Drive view:
1. Open up your online Google Drive. Click on the gear icon in the top right corner. In the drop down menu mouse over Upload settings, then click on the Convert uploaded files to Google Docs format setting to uncheck it.