Section 7(3)(v) in Tamil Nadu Electricity Grid Code, 2005
(v)All generating units, which are synchronized with the Grid, irrespective of their ownership, type and size, shall have their governors in normal, preferably at free-governor mode at all times. If any generator of over 50 MW rating is required to be operated without its governor in normal operation, the SLDC shall be immediately advised about the reason and duration of such operation. All governors shall have a droop between 3 %. and 6 % for thermal and 0 to 10 % for hydro generators.