After you install the SQL parts to enable PowerPivot for SharePoint 2013 you need to run the ‘PowerPivot for SharePoint 2013 Configuration Tool’. This configuration tool will deploy the features, services, applications and solutions that are needed by PowerPivot.
If you run this tool, you might receive a validation error stating you need to be a SharePoint Farm Administrator, even if you already have farm administrator privileges.
The user is not farm administrator. Please address the validation failures and try again