Cable operator showing/not showing PV in Tamil Nadu has no impact on TRPs at all. The contribution of the Southern States to the TRP of the GECs (Hindi based) is miniscule.
At present TRPs are, wrongly or rightly, calculated by installing TAM meters/People meters in select households and monitoring what they watch.
Majority(over 95%) of these households are in Maharashtra (Mumbai, Pune), Delhi, Gujarat, Rajasthan, Madhya Pradesh (Indore, Bhopal, Jabalpur, Ujjain) and Uttar Pradesh (the KAVAL cities).
It's what these people watch dictate the TRPs, storyline and even location. The current top shows as per TRP chart are Rajasthan, Gujarat and Mumbai based.