How can I fetch filtered data via OData feed?

You can filter records fetched via OData through Power Bi conditionally.

1.Fetch selected fields 
https://instance_url/restapi/V1/OData/Pull/odata.svc/Contacts?$select=firstname,lastname

2.Fetch with conditions 
https://instance_url/restapi/V1/OData/Pull/odata.svc/Contacts?$filter=firstname eq 'Mark'

3.Fetch with limit 
https://instance_url/restapi/V1/OData/Pull/odata.svc/Contacts?$top=10

4.Skip few records from the result (we can use this for paging) 
https://instance_url/restapi/V1/OData/Pull/odata.svc/Contacts?$skip=10&$top=10

5.Count the total number of records 
https://instance_url/restapi/V1/OData/Pull/odata.svc/Contacts/$count

Refer : OData Feed