Section 9(2)(v) in Tamil Nadu Electricity Grid Code, 2005
(v)The SLDC shall in parallel issue the weekly bills for UI charges and Reactive Energy Charges to all constituents by Tuesday for the seven-day period ending on the penultimate Sunday mid night. These bills shall have a higher priority, and the generating stations and beneficiaries / distribution licensees shall pay the billed amounts within 10 days of billing date.