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State Regulatory Handbook

Tamil Nadu Deviation Settlement Mechanism (DSM) Guide

Tamil Nadu has extensive legacy and modern wind assets in Muppandal and Kayathar passes alongside growing solar installations in Kamuthi and southern districts.

Last reviewed: 12 Aug 2026
Reviewer: Mohit Kumar Singh
Order: 2023 (01 Jan 2024)

SLDC Submission & Revision Windows — Tamil Nadu

Tamil Nadu SLDC (TANTRANSCO)
Day-Ahead Deadline
10:00 AM day-ahead
Intra-Day Revisions
Up to 16 Revisions
Gate Closure Lead
6 Blocks (1.5 Hours)

Revision submissions through TANTRANSCO portal with 6 blocks lead time.

Applicable Deviation Penalty Slabs

Under TNERC (Forecasting, Scheduling and Deviation Settlement Mechanism for Solar and Wind Generating Sources) Regulations, the following deviation penalty schedule is enforced per 15-minute time block:

Deviation BandRegulatory Penalty RuleSettlement Multiplier
0% – 10%Within tolerance band: Nil penaltyNil
10% – 20%10% to 20% deviation: 10% of PPA Tariff≈ ₹0.31/kWh
20% – 30%20% to 30% deviation: 20% of PPA Tariff≈ ₹0.62/kWh
30% – Above 30%>30% deviation: 30% of PPA Tariff≈ ₹0.93/kWh

High-Wind Monsoon Season & Southern Corridor Evacuation

During the southwest monsoon (May to September), wind speeds through the Palghat and Shencottah gaps surge, creating high evacuation loading on TANTRANSCO 110/230 kV lines.

Grid backing down instructions during peak wind periods require tight schedule revision coordination to claim deemed generation benefits.

Common Operational Failure Modes
  • •Severe wind gust ramps in pass corridors during pre-monsoon.
Local Grid Nuances
  • •High concentration of low-voltage connected sub-50 MW wind farms.

Automate Tamil Nadu SLDC Scheduling with REFlux

REFlux integrates directly with Tamil Nadu SLDC (TANTRANSCO) submission templates, tracking the 6-block revision window and providing single-click schedule revisions.

Calculate Tamil Nadu DSM Penalty →Book a Demo

Other State DSM Guides

Rajasthan DSM Rules →Gujarat DSM Rules →Karnataka DSM Rules →Maharashtra DSM Rules →
This guide is general information based on public regulatory orders and does not constitute formal legal counsel.