I have used different queries based on DMVs which let you extract data from a Power Pivot model in order to create a design documentation: list of tables, columns, calculated columns formulas, measures ...etc.
Yet, I have not found the way to extract a list of all tables relationships in the model. Sure enough, I can copy/paste it from the PowerPivot window.
But would someone have a query that extracts table relationships ?
I do not believe that there is any $system based DMV which returns relationship information.
You can get this information from an SSAS Tabular instance using a DISCOVER_CSDL_METADATA call, but that returns an XML document with the all the metadata and I don't know of any easy way to call that against a PowerPivot model (unless it's deployed to sharepoint)
The following is an example query that I ran against a tabular SSAS instance.
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