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© [Regd. No. TN/CCN/467/2012-14.
GOVERNMENT OF TAMIL NADU [R. Dis. No. 197/2009.
2026 [Price: Rs. 12.00 Paise.
TAMIL NADU
GOVERNMENT GAZETTE
PUBLISHED BY AUTHORITY
No. 24] CHENNAI, WEDNESDAY, JUNE 17, 2026
Aani 3, Parabhava, Thiruvalluvar Aandu–2057
Part VI—Section 2
Notifications of interest to a section of the public
issued by Heads of Departments, etc.
NOTIFICATIONS BY HEADS OF DEPARTMENTS, ETC.
CONTENTS
Pages.
TAMIL NADU ELECTRICITY REGULATORY COMMISSION, CHENNAI-600 032.
Tamil Nadu Electricity Regulatory Commission (State Load Dispatch Centre Functions and
Accountability) Regulations, 2026 .. .. .. .. .. .. .. 174-202
DTP—VI-2 (24) [173]174
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
NOTIFICATIONS BY HEADS OF DEPARTMENTS
TAMIL NADU ELECTRICITY REGULATORY COMMISSION, CHENNAI-600 032.
Tamil Nadu Electricity Regulatory Commission (State Load Dispatch Centre Functions and Accountability)
Regulations, 2026
(Notification No. TNERC/SLDC (F&A) /26-1/2026 dated 25-05-2026)
(Lr.No. TNERC/Legal/1375/D.No. 871/2026)
No. VI(2)/28/2026.
Preamble
In exercise of the powers conferred under Sections 32(3), 33(1), 86(1)(h), 86(1)(e), 86(1)(i), 86(1)(k), 181 and
other enabling provisions of the Electricity Act, 2003, the Commission hereby makes the following Regulations,
namely, the Tamil Nadu Electricity Regulatory Commission (State Load Dispatch Centre Functions and Accountability)
Regulations, 2026, to govern the functions, operational accountability, transparency framework, and reporting
obligations of the State Load Dispatch Centre.
2. These Regulations are framed having regard to the statutory distinction between the State Load Dispatch
Centre and the State Transmission Utility / transmission licensee under the Act, the Commission’s duty to specify
the Tamil Nadu Electricity Grid Code, and the need to ensure transparent, reasoned, and auditable exercise of
operational powers by the SLDC.
Chapter I — Preliminary
1. Short title, commencement and control period
1.1 These Regulations may be called the Tamil Nadu Electricity Regulatory Commission (State Load Dispatch
Centre Functions and Accountability) Regulations, 2026.
1.2 They shall come into force on the date of their publication in the Official Gazette.
2. Scope and application
2.1 These Regulations shall apply to the State Load Dispatch Centre, State Transmission Utility, intra-State
transmission licensees, generating companies, distribution licensees, open access customers, traders, storage
operators, qualified coordinating agencies, and all other entities whose scheduling, dispatch, metering, energy
accounting, or grid operation is coordinated by the SLDC.
2.2 These Regulations shall govern:
(a) discharge of statutory and grid-code functions by the SLDC;
(b) accountability standards for operational directions and system operation decisions;
(c) maintenance of records, event logs and curtailment logs;
(d) reporting, transparency and compliance obligations;
(e) determination, recovery, truing-up and sharing of SLDC fees and charges;
and
(f) consequences of non-compliance.
3. Definitions
In these Regulations, unless the context otherwise requires:
3.1 “Act” means the Electricity Act, 2003.
3.2 “Annual SLDC Charges” means the aggregate revenue requirement approved by the Commission for meeting
the annual expenditure of the SLDC, including all admissible components specified in these Regulations, analogous
to the Annual LDC Charges framework recognised in the CERC (Fees and Charges of Regional Load Dispatch
Centres and other related matters) Regulations, 2024.
3.3 “Backing down instruction” means any instruction issued by the SLDC directing a generating station, storageJune 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 175
facility, distribution licensee, open access user, or any other grid user to reduce, regulate, reschedule, curtail, or
cease injection or drawal, whether in full or in part.
3.4 “Curtailment event” means any event in which injection, scheduling, dispatch, evacuation or drawal is
reduced, denied or interrupted pursuant to an SLDC instruction, transmission constraint, over-voltage, line outage,
grid-security measure, or any other system-operational reason.
3.5 “Event log” means the time-stamped electronic record maintained by the SLDC, and where electronic recording
is temporarily unavailable, a manual record, of all operational instructions, switching operations, contingencies,
constraints, dispatch interventions, curtailment events, restoration actions and related reasons.
3.6 “Grid Code” means the Tamil Nadu Electricity Grid Code, 2026 specified by the Commission, as amended
from time to time.
3.7 “Must-run stations” means a generating station or class of generating stations that the SLDC shall not
curtail generation except for grid security reasons, as notified by the Commission or specified in the Tamil Nadu
Electricity Grid Code, 2026 / (Forecasting, Scheduling and Deviation Settlement and related matters for Wind
and Solar Generation) Regulations, 2024. Without limiting the generality of the foregoing, nuclear power stations,
run-of-river hydro stations, and renewable energy generating stations (including wind and solar) shall ordinarily be
treated as must-run stations unless otherwise directed by the Commission.
3.8 “Reasoned instruction” means an operational instruction that records the time, affected entity, quantum,
duration, system condition, legal or technical basis, and the officer authorizing the direction.
3.9 “SLDC” or “System Operator” means the State Load Dispatch Centre established under Section 31 of the
Electricity Act, 2003, responsible for the integrated operation, scheduling, dispatch and supervision and control of
the power system in the State in accordance with the provisions of the Act, the applicable Grid Code, and the
Regulations, orders and directions of the Commission.
3.10 “SLDC ARR” means the aggregate revenue requirement of the SLDC determined by the Commission under
these Regulations.
3.11 “STU” means the State Transmission Utility notified under Section 39 of the Act.
3.12 “Qualified Co-ordinating Agency” (or “QCA”) means Qualified Coordinating Agency as defined in TNERC
(Forecasting, Scheduling and Deviation Settlement for Wind and Solar Generation) Regulations, 2024;
3.13 “TNSPC” means Tamil Nadu State Power Committee (TNSPC) constituted by the Commission.
3.14 “State Sub Load Dispatch Centre” means Sub Load Dispatch Centre for local control at various places
in Tamil Nadu.
3.15 “Renewable Energy Management Centre” or “REMC” means a control centre that supports Load Dispatch
Centres in forecasting, scheduling, and real-time monitoring of renewable energy for reliable grid operation.
3.16 “Digital Reasoned Instruction” means an operational instruction generated, time-stamped, stored, and
retrievable through an automated digital module integrated with the SCADA/EMS or scheduling platform, containing
all particulars specified under Regulation 6.2.
3.17 Words and expressions not defined herein but defined in the Act, rules, or regulations framed thereunder
shall have the meanings respectively assigned to them therein.
Chapter II — Functions and operational duties
4. General functions of SLDC
4.1 The SLDC shall discharge the functions assigned under Sections 31, 32 and 33 of the Act and the
Tamil Nadu Electricity Grid Code, including integrated operation of the power system in the State, scheduling
and dispatch of electricity, monitoring of grid operations, accounting of electricity transmitted through the State
grid, supervision and control over intra-State grid operations, and such other functions as may be assigned by
the Commission from time to time.
4.2 The SLDC shall perform system operation functions independently, neutrally and in a non-discriminatory manner.
It shall not unduly prefer or decline any class of users.
4.3 The SLDC shall exercise its powers only for secure, reliable and economic operation of the grid, and every176
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
material operational intervention shall be demonstrably traceable to the Act, the Grid Code, Commission orders,
or a recorded real-time system requirement.
4.4 The SLDC shall discharge all functions, obligations, and roles assigned to it under the TNERC (Grid Connectivity
and Intra-State Open Access) Regulations, TNERC (Deviation Settlement Mechanism and related matters) Regulations,
2019, TNERC (F&S for Wind and Solar) Regulations, and all Detailed Procedures, Standard Operating Procedures,
and administrative orders issued by the Commission from time to time, as amended.
Provided that, where any inconsistency arises between these Regulations and the aforesaid Regulations, the
Commission may issue appropriate clarificatory directions to resolve such inconsistency.
4.5 The SLDC shall exercise its powers as laid down in the Detailed Procedure for management of RE curtailment
for wind and solar generation in accordance with Tamil Nadu Electricity Regulatory Commission (Forecasting,
Scheduling and Deviation settlement and Related Matters for Wind and Solar Generation) Regulations, 2024.
Provided that, in case of any inconsistency between the said Detailed Procedure and these Regulations, the
accountability and reporting provisions of these Regulations shall prevail, subject to directions issued by the
Commission.
4.6 The role of the SLDC under the aforesaid Detailed Procedure shall be as follows:
a) SLDC shall develop a web-based application for the following purposes within a period of twelve (12)
months from the date of commencement of these Regulations, or as may be extended by the Commission for
justified reasons.
(i) Uploading of Day ahead and Week ahead RE Generation Forecasts.
(ii) Uploading of the revisions in Schedules in accordance with RE F&S Procedures and Regulations.
(iii) Communication of Grid Constraints and curtailments if any and restorations thereof.
(iv) Maintaining the data of Load-Generation balance in real time and the deviation of State at State periphery
and transmission line loading in real time.
b) SLDC shall be responsible for scheduling, communication, coordination with Licensees/QCAs/Lead Generator
for RE generation.
c) SLDC shall undertake RE generation forecast on the basis of the weather data provided by Indian
Meteorological Department (IMD) or any other weather data with the objective of ensuring secure grid operation.
d) SLDC shall monitor congested situations in the intra-state transmission network and shall be responsible
for issuance of remedial measures for the same. The action on remedial measures initiated by the SLDC shall
be taken by the STU/ Distribution Licensee.
e) SLDC shall maintain records and accounts of the time block-wise Schedules, the actual generation injected
and the deviations, for the Pooling Sub-Station and the individual Generator(s) separately.
f) SLDC shall maintain records of curtailment events along with causes for such curtailment. SLDC shall
certify the events of curtailment, duration of curtailment to facilitate RE Generators/QCAs/Lead Generator to
estimate loss of generation. However, it is clarified that claims for loss of generation and the methodology for
computation of such loss shall be governed by the ‘Detailed Procedure for Management of RE Curtailment for
Wind and Solar Generation’ issued by the Commission in 2024, as may be amended from time to time, or the
terms of the relevant PPA, or any other guidelines issued by the Central/State Government or the Commission.
g) The SLDC shall discharge the roles and responsibilities assigned to it in the Detailed Procedure for Management
of RE Curtailment issued by the Commission under the TNERC F&S Regulations 2024, as amended from time to time.
Provided that, in the event of any inconsistency between that Procedure and these Regulations, the Commission
may issue clarificatory directions, and pending such clarification, the provisions of these Regulations shall prevail
to the extent of such inconsistency.
4.7. Merit Order / Mus-trun
4.7.1 The SLDC shall schedule and dispatch electricity in accordance with the principle of Merit Order Dispatch
read with the Tamil Nadu Electricity Grid Code and the TNERC (Forecasting, Scheduling and Deviation Settlement)
Regulations. Must-run stations, including renewable energy generating stations, nuclear power stations, and run-of-river
hydro stations, shall not be curtailed except for grid security reasons duly recorded under Regulation 6.3.
4.7.2 The SLDC shall include a summary of Must-Run curtailment events and Merit Order compliance in its
quarterly compliance report submitted under Regulation 11.2.June 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 177
4.8 Scope of Operational Accountability: The accountability, logging, reporting and operational transparency provisions
of these Regulations shall apply equally to operational interventions affecting:
(a) conventional generating stations including thermal, hydro and nuclear stations;
(b) reserve regulation and frequency control actions;
(c) reactive power management and voltage control measures;
(d) transmission switching operations and outage coordination;
(e) load shedding and restoration activities;
(f) congestion management involving conventional generation corridors and
(g) frequency control, inertial response, and primary/secondary reserve activation.
5. Relationship with STU and other entities
5.1 The STU / transmission licensee shall remain responsible for planning, augmentation, maintenance and
development of an efficient and coordinated intra-State transmission system for smooth flow of electricity, while
the SLDC shall remain responsible for real-time operation, scheduling, dispatch, and grid-security decisions.
5.2 No operational direction by the SLDC shall be construed to shift the statutory obligation of the STU to plan,
strengthen, maintain and augment the transmission system.
5.3 Where a recurring operational restriction arises from transmission inadequacy, line failure, transformer outage,
voltage instability, inadequate reactive support, delayed augmentation, or any persistent network bottleneck, the SLDC
shall record the same separately as a transmission-system constraint and notify the STU and the Commission in
accordance with Regulation 14 and related provisions of these Regulations.
5.4 The SLDC shall not cite generic “grid conditions” or “system constraints” as a substitute for specific recorded
reasons where the actual cause is attributable to identifiable transmission-system limitations.
5.5 Institutional safeguards:
5.5.1 In order to preserve the functional distinction between the SLDC and the STU, and to ensure operational
neutrality, the following safeguards shall ensure the institutional independence of SLDC — particularly regarding:
(a) freedom from undue influence by the STU in scheduling and dispatch decisions;
(b) separate staffing/cadre or terms for deputation;
(c) financial decision-making autonomy; and
(d) prohibition on the STU issuing directions to SLDC on operational matters outside the Grid Code framework.
5.5.2 In the discharge of its statutory and operational functions, the State Load Dispatch Centre (SLDC) shall act
independently as contemplated under Section 31(2) of the Act and shall not be subject to the direction or control
of the State Transmission Utility, any transmission licensee, or any other commercial entity.
5.5.3 Where any officer of the SLDC receives any direction from a superior authority within the State Transmission
Utility hierarchy which is inconsistent with, or requires deviation from, the statutory functions and obligations of
the SLDC, such officer shall record such direction in writing and forthwith report the same to the Commission.
5.5.4 The Commission may, from time to time, issue such directions as it deems appropriate with respect to
staffing, reporting structure, and other institutional safeguards to ensure the functional independence, neutrality,
and integrity of the SLDC.
5.5.5 (1) The Commission shall, within six (6) months from the date of commencement of these Regulations,
examine the institutional framework for the establishment of the State Load Dispatch Centre (SLDC) as an
independent entity under Section 31(2) of the Electricity Act, 2003.
5.5.5 (2) Upon such examination, the Commission may make appropriate recommendations in writing to the State
Government for establishing the SLDC as a separate Government company, authority, or corporation.
5.5.5 (3) The recommendation under sub-regulation (1) shall, inter alia, include:178
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
(a) proposed legal structure (Government company under the Companies Act, 2013, or authority/corporation
under a State Act);
(b) proposed staffing framework and cadre separation from STU;
(c) proposed financial autonomy and budgetary mechanisms;
(d) proposed timeline for operationalisation; and
(e) any other matter considered necessary by the Commission to ensure functional independence and
operational neutrality of the SLDC.
5.5.5 (4) The State Government shall respond to the Commission’s recommendation within three (3) months of its
receipt, communicating the action taken or proposed to be taken, along with a clear timeline for implementation.
Where the State Government decides not to accept the recommendation in whole or in part, it shall record in
writing the reasons therefor.
5.5.5 (5) If the State Government fails to respond within the stipulated period of three months, or if the response
does not contain a clear and time-bound action plan for implementation, the Commission shall submit a report
to the State Government and may communicate the status to the attention of the Ministry of Power, Government
of India, and the Central Electricity Authority (CEA) for appropriate intervention.
5.5.5 (6) Pending the establishment of SLDC as a separate Government company or authority under Section 31(2)
of the Act, the Commission shall continue to monitor compliance with the institutional safeguards under these
Regulations and may issue such interim directions as are necessary to ensure functional separation, including
distinct reporting lines, separate budget heads, and prohibition of common executive control over SLDC and STU
operational matters. Prohibition of common executive control shall be construed to include, but not be limited to,
the same individual holding the position of Chairperson or Managing Director (CMD) of both the STU and the
SLDC. Any common control in existence on the date of commencement of these Regulations shall be discontinued
within ninety (90) days of such commencement.
5.5.5 (7) The STU shall comply with all interim directions issued by the Commission under sub-regulation (5).
Non-compliance by the STU with any such direction shall be deemed a contravention of these Regulations and
shall attract action under Sections 142 and 146 of the Electricity Act, 2003.
6. Duty of transparent decision-making
6.1 Issuance and recording of operational directions
(1) Every instruction relating to backing down, rescheduling, curtailment, load shedding, congestion management,
or any comparable intervention affecting injection or drawal of power shall ordinarily be issued through a reasoned
written direction, including through electronic means.
(2) In cases of immediate emergency requiring urgent operational intervention, the SLDC may initially issue oral
directions. Such directions shall be reduced to writing electronically within the close of the shift during which the
direction was issued or within four (4) hours from the time of issue, whichever is earlier.
(3) Where cascading disturbances or widespread grid events require sustained operational intervention involving
multiple sequential directions, the SLDC may maintain a consolidated post-event log recording the sequence of
operational instructions issued during the event.
(4) The consolidated postevent log referred to in sub-regulation (3) shall be completed within four (4) hours from
restoration of normal grid conditions or by the end of the full shift immediately following such restoration, whichever
is later, subject to a maximum period of eight (8) hours from restoration.
(5) The post-event log shall form part of the event log maintained under Regulation 8 of these Regulations.
Provided that, where restoration activities extend beyond eight (8) hours owing to the scale or complexity of the
disturbance, the SLDC may complete the post-event log within twenty-four (24) hours from restoration of normal
grid conditions, with interim updates being recorded at intervals not exceeding eight (8) hours. The post-event log
under this Regulation shall be distinct from the detailed post-event analysis under Regulation 12.
6.1A Digital reasoned instruction module
The SLDC shall implement a digital reasoned instruction module integrated with the scheduling system,
including SAMAST or an equivalent SCADA/EMS platform, enabling automatic generation, timestamping, storage
and retrieval of all operational instructions, subject to the transitional timelines specified under Regulation 11A.June 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 179
6.1B Technical standards and interim protocol
(1) The Commission may, under Regulation 25 relating to Practice Directions, specify technical standards and
phased implementation timelines for the digital systems referred to in Regulation 6.1A, which shall not exceed
eighteen (18) months from the date of commencement of these Regulations.
(2) The SLDC shall submit to the Commission, within three (3) months from the date of commencement of these
Regulations, a detailed implementation plan for such digital systems, including timelines, architecture and resource
requirements.
(3) In the interim, the SLDC shall implement a hybrid manualdigital logging protocol to ensure compliance with
the substantive requirements of Regulation 6.2.
6.2 Contents of a reasoned instruction
A reasoned instruction shall, at a minimum, state:
(a) the date and exact time of issue;
(b) the name of the affected entity or pool / category of entities;
(c) the quantum and expected duration of restriction;
(d) the technical or legal reason for the instruction;
(e) the technical or operational category of the event (security, congestion, voltage, outage, frequency
maintenance, reserve, protection system operation, or transmission inadequacy) and the specific Tamil Nadu Electricity
Grid Code, Regulation, protocol, or operating procedure invoked in support of the instruction, where applicable;
(f) the name and designation of the officer authorising the instruction; and
(g) the quantum of power curtailed in Megawatt hours (MWh), and, where monthly aggregation is required,
in Million Units (MU), separately for wind and solar where applicable.
6.3 Must-run curtailment
Where a must-run station is curtailed:
(a) the SLDC shall record plantspecific or corridors-pecific reasons, and where plants-pecific reasons cannot
be immediately determined during real-time operation, the SLDC shall record the system-level reason and update,
as far as practicable, with plant-specific details within forty-eight (48) hours based on post-event analysis;
(b) where curtailment arises due to transmission constraints including corridor limitations, substation capacity
constraints or network inadequacies, the same shall be recorded as a transmission-system constraint;
(c) such cases shall be dealt with in accordance with Regulation 14 and Regulation 15; and
(d) such recording shall not dilute the obligation of the STU to undertake timely augmentation.
7. SCADA Monitoring and Control Room Operations
7.1 The SLDC control room shall be manned round the clock by qualified engineers to monitor real-time data of
all categories of generation and the transmission system through SCADA/EMS systems.
7.2 The SLDC shall ensure:
(a) round-the-clock manning by qualified engineers;
(b) staffing as per Ministry of Power Workforce Adequacy Guidelines;
(c) SCADA/EMS data integrity;
(d) backup systems and disaster recovery; and
(e) cyber-security protocols.180
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
Chapter III — Accountability, logging and reporting
8. Mandatory electronic logs
8.1 The SLDC shall maintain, in secure electronic form, the following auditable records:
(a) master event log;
(b) curtailment and backing down log;
(c) reasoned instructions log (indexed by entity, date, and event category);
(d) congestion log;
(e) transmission constraint log;
(f) voltage excursion log;
(g) system disturbance and contingency log;
(h) restoration log;
(i) scheduling revision log;
(j) communications log for oral and written directions;
(k) compliance log for Commission, RLDC, NLDC and CEA directions; and
(l) quantum of energy lost due to curtailment in Million Units (MU), separately for wind and solar.
Provided that, where electronic systems are temporarily unavailable due to technical failure, manual records may
be maintained and digitised within seventy-two (72) hours of restoration.
8.2 All logs shall be timesynchronised and preserved in retrievable form for not less than seven (7) years.
Provided that where a record is the subject of or relevant to any pending proceedings before the Commission,
the Appellate Tribunal for Electricity, or any court, such record shall be preserved until the final resolution of such
proceedings, notwithstanding the expiry of the seven-year period.
8.3 The event log shall, wherever available, be corroborated by SCADA / EMS data, voice logs, switching records,
outage data, and operator notes.
Provided that implementation of the record-maintenance and compliance requirements under this Regulation shall be
subject to phased augmentation of manpower and technical infrastructure in accordance with applicable Government
of India / Ministry of Power guidelines and approved staffing norms.
9. Curtailment and backing down log
9.1 For each curtailment event, the SLDC shall record at least the following particulars:
(a) date and time of commencement and end;
(b) identity of the affected entity or class of entities;
(c) schedule prior to curtailment and actual permitted quantum;
(d) feeder / bay / substation / corridor involved;
Provided that, where feeder / bay-level details are not directly available with the SLDC in real time, the SLDC
shall record the instruction issued to the Qualified Coordinating Agency (QCA) or entity, and the concerned QCA
or generating entity shall provide feeder / bay-level implementation details to the SLDC within seven (7) days;
(e) exact reason for curtailment;
(f) whether the cause was attributable to generation balancing, congestion, transmission failure, voltage issue,
protection operation, maintenance, reserve requirement, or force majeure;
(g) alternative measures considered and reasons for non-adoption;
(h) whether similarly situated entities were treated alike;June 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 181
(i) restoration time and manner of restoration; and
(j) estimated quantum of energy curtailed.
9.2 Where curtailment affects mustrun stations, the SLDC shall additionally certify whether the curtailment was
unavoidable for grid security and whether less restrictive alternatives were considered.
9.3 The curtailment log shall be updated contemporaneously during the shift in which the curtailment event occurs
and, in all cases, not later than the end of the shift immediately following the shift in which such curtailment
event occurred.
9.4 (a) For planned curtailment arising from maintenance, outages, or scheduled shutdown, the SLDC shall
communicate the same to affected HT / EHT entities at least one (1) day in advance.
(b) For emergency curtailment arising from sudden contingencies, the SLDC shall communicate the same to
affected entities as soon as practicable, and in any case not later than fifteen (15) minutes before implementation,
or, where prior communication is not possible due to the imminence of the grid-security threat, immediately after
implementation, with the reason for non-communication recorded in the event log.
10. Accountability for speaking and evidence-based action
10.1 No material operational action affecting rights, scheduling, dispatch, evacuation, or commercial settlement
shall be defended before the Commission on the basis of vague, aggregated, or generic data unsupported by
event-specific records.
10.2 Where the Commission or any adjudicatory forum seeks plant-specific, event-specific, feeder-specific, or
date-specific justification for SLDC action, the SLDC shall furnish such particulars in a verifiable and indexed form.
10.3 Failure to maintain or produce contemporaneous logs, reasons, supporting data, or event-wise explanations
in accordance with these Regulations may give rise to an adverse inference against the SLDC in proceedings
before the Commission.
Provided that no adverse inference shall be drawn where failure to maintain or produce records is attributable to:
(i) emergency grid conditions requiring sustained operational intervention;
(ii) communication or telemetry failure;
(iii) non-availability of field data from concerned entities; or
(iv) force majeure events, subject to the SLDC demonstrating reasonable efforts to reconstruct records.
Reasonable efforts shall include, at a minimum, retrieval of available SCADA/EMS data, voice logs, and
operator notes within seven (7) days of restoration.
10.4 The SLDC shall ensure that every affidavit, reply, compliance report, or operational note filed before the
Commission is based on contemporaneous records and is certified by an officer not below such rank as may
be designated by the Commission.
11. Monthly and quarterly reporting
11.1 The SLDC shall publish on its website, within thirty (30) days from the end of each month, a report containing:
a) total number and duration of curtailment events;
b) entity-wise and category-wise curtailed quantum;
c) corridor-wise congestion instances;
d) major voltage excursions and mitigation taken;
e) outages materially affecting scheduling or evacuation;
f) summary of directions issued to generating stations, storage systems and distribution licensees; and
g) pending recurring constraints requiring STU action.
h) estimated quantum of energy curtailed in Million Units (MU) during the month, separately for wind and
solar; and182
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
i) a link, portal, dashboard, or other suitable platform through which real-time generation, demand, injection,
withdrawal, scheduling, and other operational data, as determined by the SLDC, are made accessible to stakeholders
in accordance with these Regulations and applicable data access protocols.
11.2 The SLDC shall submit to the Commission, within 30 days from the end of each quarter, a certified
compliance report containing:
a) all curtailment events involving must-run stations;
b) all events exceeding the threshold duration or quantum specified by the Commission;
c) status of implementation of prior Commission directions;
d) recurring system constraints and proposals for mitigation; and
e) instances of non-compliance by users, if any.
11.3 The Commission may direct publication of anonymised or aggregated data where confidentiality is justified,
but confidentiality shall not be used to defeat accountability.
11.4 Simultaneously with website publication, the SLDC shall submit the monthly report to the Commission in
editable digital format. The Commission may, by practice direction, specify the standard format, granularity of data,
and the minimum fields to be populated. Where publication of entity-specific data is disputed on confidentiality
grounds, the SLDC shall seek Commission directions within the reporting period.
Provided that where generator-wise or feeder-wise curtailment and operational data are not directly available
with the SLDC in real time, the SLDC shall record and publish the information available within its operational
domain, and the concerned Qualified Coordinating Agency (QCA), Distribution Licensee, or generating entity shall
furnish the detailed entity-level information to the SLDC within such time as may be specified by the SLDC.
11.5 The SLDC shall communicate, through its official website, designated portal, or any other appropriate
communication platform, information relating to any major transmission congestion, breakdown of power transformers
or transmission elements, or other significant grid events, so as to ensure timely dissemination of operational
information to all stakeholders connected to or affected by grid operations.
11A Digital system implementation
(1) The SLDC shall implement the digital systems required for compliance with these Regulations, including
automated logging, reporting, curtailment tracking, and digital reasoned instruction modules, within a period of
eighteen (18) months from the date of commencement of these Regulations, or as may be extended by the
Commission for justified reasons.
(2) During the transition period, compliance may be ensured through a combination of manual and digital systems,
provided that all records are maintained in auditable form.
(3) The SLDC shall submit to the Commission, within three (3) months, a system implementation plan including
timelines, architecture, and resource requirements.
12. Incident review and post-event analysis
12.1 In every event involving large-scale curtailment, repeated backing down, islanding, major voltage violation,
prolonged congestion, or system disturbance, the SLDC shall conduct a post-event analysis within seven days.
12.2 The post-event analysis shall identify:
a) root cause;
b) chronology of operator actions;
c) whether Tamil Nadu Electricity Grid Code provisions were complied with;
d) whether the cause was operational, infrastructural or mixed;
e) whether STU, transmission licensee, generator, distribution licensee, or another user contributed to the
event; and
f) corrective and preventive action with timeline.June 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 183
12.3 Such analysis shall be furnished to the Commission and the affected entities where the event has
commercial or operational consequences.
Chapter IV — GRID CODE INTERFACE, SYSTEM RESPONSIBILITY AND COORDINATION
13. Harmonisation with the Grid Code and other Regulations
13.1 These Regulations shall be read in conjunction with the Tamil Nadu Electricity Grid Code, 2026 (hereinafter
referred to as the “Grid Code”) and shall supplement, but not derogate from, the provisions thereof.
13.2 In the event of any inconsistency between these Regulations and the Grid Code:
(a) matters relating to real-time system operation, scheduling, dispatch, congestion management, outage
coordination, frequency and voltage control shall be governed by the Grid Code;
(b) matters relating to transparency, accountability, recording of reasons, reporting, audit obligations, and
post-event analysis shall be governed by these Regulations.
13.2A Overlapping applicability of Grid Code and these Regulations
(1) Where any action or direction of the SLDC involves operational matters governed simultaneously by the Grid
Code and these Regulations, the provisions of both frameworks shall apply in their respective fields.
(2) The provisions of the Grid Code shall govern the technical validity, operational necessity, implementation, and
compliance requirements relating to such operational action or direction.
(3) The provisions of these Regulations shall govern the procedural aspects relating to recording, documentation,
communication, reporting, transparency, and post-event accountability obligations associated with such action or
direction.
(4) In the event of any ambiguity or operational overlap in the application of the Grid Code and these Regulations,
the Commission may, either suo motu or upon a request made by the Tamil Nadu State Load Dispatch Centre
(TNSLDC), issue appropriate clarificatory practice directions or procedural guidelines specifying the manner of
resolution and applicability on a case-to-case basis.
13.2B Overlapping applicability with DSM and Forecasting & Scheduling Regulations
(1) Where any inconsistency or operational overlap arises between these Regulations and:
(a) the Tamil Nadu Electricity Regulatory Commission (Forecasting, Scheduling and Deviation Settlement and
related matters for Wind and Solar Generation) Regulations, including subsequent amendments thereto;
(b) the Tamil Nadu Electricity Regulatory Commission (Deviation Settlement Mechanism and related matters)
Regulations, 2019, including subsequent amendments thereto; or
(c) any Detailed Procedure, Manual, or operational framework issued thereunder, the provisions specified in
this Regulation shall apply.
(2) Matters relating to real-time scheduling, dispatch, grid balancing, deviation management, backing down, revision
of schedules, and operational implementation shall be governed by:
(a) the Tamil Nadu Electricity Grid Code Regulations, 2026; and
(b) the applicable Forecasting, Scheduling and Deviation Settlement Regulations and DSM Regulations referred
to in sub-regulation (1).
(3) Matters relating to recording of directions, communication protocols, documentation, statement of reasons,
event logging, transparency, accountability, reporting, and audit obligations shall be governed by these Regulations.
(4) In the event of any ambiguity or practical difficulty in the application of these Regulations alongside the
Regulations and Procedures referred to in sub-regulation (1), the Commission may, either suo motu or upon a
request made by the Tamil Nadu State Load Dispatch Centre (TNSLDC), issue appropriate clarificatory practice
directions or procedural guidelines specifying the manner of resolution and applicability on a case-to-case basis.
13.3 The SLDC shall ensure that all actions taken under these Regulations remain consistent with the operational
framework prescribed under the Grid Code.
13.4 Nothing contained in these Regulations shall be construed to limit, dilute or override the provisions of the
Grid Code except to the extent expressly provided.184
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
13.5 The Commission may, by order or Practice Direction, issue clarifications to resolve any overlap or inconsistency
between these Regulations, the Grid Code, and other applicable Regulations.
13A. Interface with RLDC, NLDC and Central Regulations
(1) The SLDC shall coordinate with the Regional Load Dispatch Centre (RLDC) and National Load Dispatch
Centre (NLDC) in accordance with:
(a) the Central Electricity Regulatory Commission (Indian Electricity Grid Code) Regulations;
(b) the Central Electricity Regulatory Commission (Deviation Settlement Mechanism) Regulations;
(c) the Central Electricity Regulatory Commission (Fees and Charges of Regional Load Despatch Centre and
other related matters) Regulations, 2024; and
(d) all other applicable Central Regulations and directions issued from time to time.
(2) In matters involving inter-State scheduling, dispatch, grid security, frequency control, or real-time system
operation, directions issued by the RLDC or NLDC shall be complied with by the SLDC in accordance with the
Act and applicable Regulations.
(3) The obligations of the SLDC under these Regulations shall be interpreted in a manner consistent with
the inter-State operational framework, and no provision herein shall be construed to limit compliance with RLDC
or NLDC directions.
(4) Where a direction of RLDC or NLDC necessitates action by the SLDC affecting intra-State entities, the
SLDC shall record such direction in the event log and, where applicable, reflect the same in reasoned instructions
issued under Regulation 6.
(5) The provisions of the TNERC DSM Regulations, Forecasting and Scheduling Regulations, and Regulations
relating to SLDC fees, charges and ARR shall, to the extent practicable and applicable to the State grid, be
maintained in alignment with the corresponding Regulations, principles, procedures and amendments issued by
the Central Electricity Regulatory Commission from time to time, so as to ensure consistency in grid operation,
scheduling, deviation settlement, operational coordination and regulatory mechanisms.
14. Allocation of responsibility for system constraints and operational actions
14.1 The Commission shall, in any proceeding involving curtailment, congestion, or system restriction, distinguish
between:
(a) operational actions of the SLDC; and
(b) infrastructural or planning deficiencies attributable to the STU or transmission licensee.
14.2 Exclusion of SLDC Responsibility for Infrastructure-Related Curtailment
(1) The State Load Dispatch Centre (SLDC) shall not be held responsible for curtailment, backing down, load
restriction, or any operational limitation arising solely due to:
(a) transmission constraints;
(b) inadequate corridor capacity;
(c) transformer limitations;
(d) delayed system augmentation; or
(e) any other infrastructural inadequacy affecting grid operation.
(2) The exclusion under sub-regulation (1) shall apply only where the underlying causes and operational circumstances
leading to such curtailment or restriction are duly recorded and documented in accordance with these Regulations.
(3) Where the proximate or underlying cause of curtailment is attributable to persistent transmission system
weakness, inadequate evacuation infrastructure, delayed commissioning of network elements, defective transmission
lines or equipment, non-availability of reactive power support, or failure to undertake timely augmentation works,
such circumstances shall not be treated solely as an SLDC operational event merely on the ground that the
immediate operational instruction was issued by the SLDC.
(4) Nothing contained in this Regulation shall absolve the concerned transmission licensee, State Transmission
Utility (STU), or any other responsible entity from accountability arising out of infrastructural deficiency, planning
failure, inadequate maintenance, or delay in augmentation affecting grid operation.June 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 185
14.3 Where the proximate cause is arbitrary, unsupported, discriminatory, unreasoned, or inadequately recorded
exercise of dispatch power, the SLDC shall remain answerable for such operational action.
14.4 The STU or transmission licensee shall be responsible for addressing infrastructure-related constraints identified
under these Regulations.
14.5 The Commission may, based on records maintained under Chapter III, determine responsibility and issue
appropriate directions including:
(a) system strengthening measures;
(b) timelines for augmentation;
(c) accountability for recurring constraints; and
(d) any other corrective action.
14.6 The Commission may, based on the event records and evidence, apportion responsibility between the SLDC
and the STU / transmission licensee consistent with its powers under Sections 86(1)(f), 86(1)(h), 86(1)(i), 142 and
other applicable provisions of the Electricity Act 2003. Apportionment of responsibility under this Regulation shall
be without prejudice to the entitlement of any affected party to seek compensatory relief in accordance with law.
15. Identification and reporting of recurring constraints
15.1 The SLDC shall identify transmission corridors, substations, or system elements where repeated congestion,
curtailment, or operational restriction occurs.
15.2 If any corridor, substation, bay, line, transformer, reactive support element, communication channel, protection
system, or control infrastructure causes repeated operational restrictions, the SLDC shall record the same in a
separate log and shall reflect the same in monthly and quarterly reports and shall issue a recurring-constraint
notification to the STU within seven days. A copy of such notification shall also be communicated to all affected
HT/EHT entities connected to the grid through appropriate communication modes, including electronic communication,
publication on the official website of the SLDC, or any other mode considered suitable by the SLDC.
15.3 A copy of such notification shall be filed with the Commission as part of the monthly report where:
(a) the same asset or corridor gives rise to five or more curtailment events in a month; or
(b) the cumulative energy curtailed from the same asset or corridor in a month exceeds such quantum as
may be specified by the Commission through Practice Directions; or
(c) any single constraint results in curtailment beyond the threshold specified by the Commission.
15.4 Where a constraint persists beyond such duration or frequency as may be specified by the Commission
through these Regulations or notified through Practice Directions, and pending such specification where a constraint
occurs repeatedly in a manner materially affecting scheduling, dispatch or evacuation, the SLDC shall notify the
STU and the Commission with:
(a) technical description of the constraint;
(b) frequency and duration;
(c) entities affected;
(d) estimated energy curtailed; and
(e) operational alternatives considered.
15.5 The STU shall submit a mitigation plan within the following timelines based on constraint categorization:
(a) Critical constraints (transformer failure, grid element failure, protection system failure) – within fifteen (15)
days, with interim remedial measures within seven (7) days;
(b) Major constraints (transmission line strengthening, corridor augmentation) – within sixty (60) days;
(c) Other constraints – within ninety (90) days
Provided that where curtailment or operational restriction continues due to pendency of STU’s mitigation plan186
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
or delay in implementation, the SLDC shall not be held accountable for such continued restriction, provided the
SLDC has duly recorded the constraint and notified the STU and Commission as required under these Regulations.
15.6 The Commission may monitor such constraints and issue directions to ensure timely resolution.
Chapter V — Fees, Charges and ARR
16. SLDC Charges and Aggregate Revenue Requirement
16.1 The State Load Dispatch Centre shall be entitled to recover its Aggregate Revenue Requirement (ARR) and
associated fees and charges in accordance with the Tamil Nadu Electricity Regulatory Commission (Determination
of State Load Dispatch Centre Fees and Charges) Regulations, 2026, as amended from time to time.
16.1A Until such Regulations come into force, the Commission may determine and approve the SLDC Fees and
Charges through orders issued from time to time.
17. Recovery and sharing of SLDC charges
17.1 The SLDC charges shall be recovered from users of the State grid in a manner determined by the Commission.
17.2 The methodology for allocation and recovery shall be specified in the Regulations referred to in Regulation
16.1 or, until such Regulations come into force, through orders issued by the Commission.
17.3 The Commission may provide for:
(a) user-wise allocation;
(b) transaction-based charges;
(c) capacity or energy-based sharing; or
(d) any hybrid mechanism.
17.4 The SLDC shall maintain proper accounts and records of charges billed and recovered and shall submit the
same for verification by the Commission.
Chapter VI — MANPOWER, CAPACITY AND OPERATIONAL READINESS
18. Staffing and workforce adequacy
18.1 The strength of manpower required for the effective functioning of SLDC shall be in accordance with the
Ministry of Power Workforce Adequacy Guidelines for Load Dispatch Centres applicable for a large SLDC such
as Tamil Nadu (approximately 144 personnel or as specified therein), as amended from time to time.
18.2 The manpower requirements for Sub Load Dispatch Centres, Renewable Energy Management Centres
(REMC), cyber security functions including Security Operations Centre (SOC) and Network Operations Centre
(NOC), Disaster Recovery Centres, and the Tamil Nadu State Power Committee shall also be assessed and
strengthened appropriately to ensure efficient grid management.
18.2A The Renewable Energy Management Centre (REMC), wherever established, shall function under the operational
oversight of the SLDC for purposes of forecasting, scheduling integration, and real-time monitoring of renewable
energy resources. Staffing, infrastructure, and operational protocols of the REMC shall be jointly assessed and
determined by the SLDC, with such manpower and budget provisions incorporated in the SLDC ARR filing.
18.3 (1) The SLDC shall, while filing the petition for determination of SLDC fees and charges for each control
period, furnish details of the existing manpower, proposed additional manpower requirement, training requirements,
and requirement of certified shift system operators.
18.3 (2) The SLDC shall, at the time of filing the True-up petition for determination of SLDC fees and charges,
furnish details of the additional manpower deployed during the control period, the number of certified shift system
operators engaged, and compliance with the staffing and certification requirements specified under these Regulations
and the applicable Regulations governing SLDC Fees and Charges.
18.3 (3) The incentives, certification benefits, load dispatch allowances, and other service-related benefits applicable
to certified shift system operators and other SLDC personnel shall be governed in accordance with the applicable
Regulations or orders issued by the Commission from time to time.
18.3 (4) The SLDC may, in consultation with the State Government, evolve an appropriate manpower retention
policy, including minimum tenure requirements for certified shift system operators and other shift personnel deployedJune 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 187
at the SLDC, so as to ensure continuity, operational reliability, institutional expertise, and retention of experienced
operational personnel.
19. Training and capacity building
19.1 The SLDC shall implement continuous training programmes for shift system operators, including:
(a) grid operation and stability;
(b) SCADA/EMS systems;
(c) renewable energy forecasting and integration;
(d) disturbance handling and restoration; and
(e) cyber security and data management.
19.2 Training programme may be conducted in coordination with:
(a) NLDC/RLDC;
(b) Central Electricity Authority;
(c) accredited training institutions.
20. Operational readiness and infrastructure
20.1 The SLDC shall ensure availability of:
(a) reliable SCADA/EMS systems;
(b) redundant communication systems;
(c) backup control centres;
(d) disaster recovery mechanisms; and
(e) cyber security infrastructure.
20.2 The SLDC shall periodically test such systems and maintain records of system readiness.
20.3 Any cyber-security incident materially affecting SLDC operations, telemetry, scheduling, dispatch, or data
integrity shall be reported to the Commission within twenty-four (24) hours along with interim mitigation measures.
Chapter VII — Compliance, Enforcement and Consequences
21. Non-compliance
21.1 Non-compliance with these Regulations, the Tamil Nadu Electricity Grid Code, or directions of the Commission
may attract action under Sections 33(5), 86, 142, 146 and other applicable provisions of the Act.
21.2 Without prejudice to Regulation 21.1, failure by the SLDC to maintain logs, furnish event-wise reasons,
comply with reporting obligations, or obey Commission directions may be treated as a separate contravention.
21.3 Repeated failure of the STU / transmission licensee to address recurring constraints reported by the SLDC
may be considered by the Commission while determining tariff, performance review, compliance directions, or
compensatory relief, consistent with the principle that the transmission utility cannot abdicate its statutory obligation
to develop and maintain the network.
21.3A Failure by any generating company, Qualified Coordinating Agency (QCA), Distribution Licensee, open access
customer, or other grid user to:
(a) provide data or records required by the SLDC for discharge of its functions;
(b) comply with a reasoned instruction issued by the SLDC under Regulation 6; or
(c) comply with reporting or data-sharing obligations under these Regulations, shall attract action under
Sections 142 and 146 of the Electricity Act, 2003, in addition to any other consequences specified in the
Tamil Nadu Electricity Grid Code or other applicable Regulations.
The SLDC shall issue a notice of non-compliance, and the entity shall rectify the default within
seven (7) days, failing which the Commission may proceed under Section 142.188
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
21.4 Any entity aggrieved by an SLDC operational direction may:
(a) make a written representation to the SLDC within five working days of the event, and the SLDC shall
respond within five working days of receipt of such representation, based on contemporaneous records;
(b) if unsatisfied, approach the Commission for expedited review; and
(c) the Commission may constitute a standing operational review mechanism or designate a technical officer
for preliminary examination of operational grievances without requiring formal proceedings.
22. Compensation and remedial directions
22.1 In an appropriate case, where the Commission, subject to adjudication under applicable law, finds that any
curtailment, evacuation failure, prolonged restriction, or operational limitation has resulted from contravention of
the Electricity Act, 2003, the applicable Tamil Nadu Electricity Grid Code Regulations, or any other applicable
Regulations of this Commission, it may issue such remedial, corrective, compensatory, restitutive, or consequential
directions as may be permissible in accordance with law.
22.2 While considering such relief, the Commission may take into account:
(a) whether the SLDC action was reasoned, contemporaneously recorded and proportionate;
(b) whether the STU had failed to maintain or augment the network;
(c) whether the affected entity complied with forecasting, scheduling and technical requirements; and
(d) whether the event was avoidable.
Chapter VIII — Miscellaneous
23. Savings and Transitional Provisions
On and from the commencement of these Regulations, any existing provisions, procedures, guidelines, manuals,
protocols, or practices governing the functions and accountability of the State Load Dispatch Centre (SLDC), to
the extent inconsistent with these Regulations, shall stand superseded.
Provided that any action taken, operational direction issued, petition filed, proceeding initiated, approval granted,
or order issued under the earlier framework shall be deemed to have been validly taken or issued and shall
continue to remain in force unless otherwise directed by the Commission.
24. Power to Relax
The Commission may by general or special order, for reasons to be recorded in writing, and after giving an
opportunity of hearing to the parties likely to be affected, relax any of the provisions of these Regulations on its
own motion or on an application made before it by an interested person.
25. Issue of Orders and Practice directions
Subject to the provisions of the Act, the Commission may from time to time issue Orders and Practice Directions
with regard to the implementation of these Regulations.
26. Power to Amend
The Commission may, at any time, vary, alter, modify or amend any provisions of these Regulations. Provided that
any such amendment shall be made in accordance with the procedure prescribed under Section 181 of the Act.
27. Power to Remove Difficulties
If any difficulty arises in giving effect to provisions of these Regulations, the Commission may, by an order,
make such provisions, not inconsistent with the provision of the Act and these regulations, as may appear to be
necessary for removing the difficulty.
28. Periodic Review
(1) The Commission shall undertake a review of these Regulations at least once every five (5) years from
the date of their commencement.
(2) Notwithstanding anything contained in sub-regulation (1), the Commission may, at any time, from time
to time, undertake a review of these Regulations, suo motu or otherwise, if it is satisfied that such review is
warranted in view of changes in law, technology, grid operation practices, market mechanisms, or any other
relevant circumstances.June 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 189
(3) Upon such review, the Commission may exercise its powers under Regulation 26 of these Regulations.
(4) Any amendment to these Regulations shall be carried out in accordance with the procedure for previous
publication as specified under Section 181(3) of the Electricity Act, 2003 and the rules framed thereunder.
29. General
(1) The Annexures I to V appended to these Regulations shall form an integral part of these Regulations.
(2) The provisions contained in the Annexures shall be binding and enforceable in the same manner as the
provisions of these Regulations.
(3) In the event of any inconsistency between the provisions of the main body of these Regulations and the
Annexures, the provisions of the main body of these Regulations shall prevail.
(4) The Commission may, from time to time, by order or practice direction issued under these Regulations,
amend, update, substitute or prescribe formats, procedures or templates specified in the Annexures, provided that
such directions are not inconsistent with the provisions of the Act and these Regulations.190
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
ANNEXURE I
Clause-wise Savings and Transitional Framework
(Refer Regulation 23)
This Annexure provides a clause-wise mapping of existing provisions, procedures, guidelines and practices relating
to SLDC functions, and their treatment under these Regulations, including savings, continuation, modification and
transition arrangements.
Sl. Existing Provision / Nature of Treatment under Remarks / Transition
No. Instrument Instrument these Regulations Mechanism
1 Tamil Nadu Electricity Grid Regulation To continue except Operational provisions
Code (existing provisions where inconsistent continue; accountability
relating to SLDC functions) provisions overridden by these
Regulations
2 SLDC Operating Procedures / Procedure Superseded to the To be aligned within 3 months;
Manuals extent inconsistent interim use permitted if not
inconsistent
3 RE Curtailment Procedures Detailed To continue with In case of conflict, these
issued under TNERC F&S Procedure overriding effect of Regulations prevail;
Regulations, 2024 these Regulations Commission may issue
clarification
4 Scheduling and Dispatch Operational Continue with Must incorporate reasoned
Protocols Protocol modification instruction requirement
5 SCADA / EMS Data Logging Operational To be upgraded Must comply with digital
Practices Practice logging under Regulation
6 and 11A
6 Curtailment Practices (generic / Practice Discontinued All curtailment must be
non-recorded) reasoned and recorded
7 Transmission Constraint Practice Replaced Now governed by Regulations
Handling (ad-hoc) 14 and 15
8 Manual Record Keeping Practice Transitional Manual record keeping
Systems continuation systems may continue during
the transition period specified
under Regulation 11A.
9 SLDC Reporting Formats Format Superseded To be replaced by Annexure
(existing) IV formats
10 Ad-hoc Instructions without Practice Prohibited All instructions must comply
traceability with Regulation 6
11 Legacy Curtailment Logs Record To be continued To be digitised within transition
period
12 STU–SLDC informal Practice Regulated Subject to institutional
coordination practices safeguards under
Regulation 5.5
13 Emergency operational Practice Allowed with Must be recorded within
practices conditions 4 hours
14 Existing ARR recovery Tariff Practice Continue Until new SLDC Fees
mechanisms temporarily Regulations are notified
15 Pending proceedings / Legal Proceedings Unaffected To continue under old
disputes framework unless directed
otherwiseJune 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 191
ANNEXURE II
Curtailment, Backing Down and Accountability Framework (Including BESS Separation)
(Refer Regulations 6, 9, 14, 15 and related provisions)
This Annexure sets out the detailed framework governing curtailment, backing down, accountability attribution, and
operational classification of events, with explicit separation of Renewable Energy (RE) and Battery Energy Storage
Systems (BESS), ensuring prevention of gaming, transparency in system operation, and verifiable audit trails.
1. Classification of Curtailment Events
(1) Curtailment events shall be classified into the following categories:
(a) Grid Security Curtailment — arising from frequency excursions, system instability, protection activation,
or contingency;
(b) Congestion Curtailment — arising from transmission corridor limitations or network constraints;
(c) Voltage Curtailment — arising from over-voltage or reactive power imbalance;
(d) Planned Curtailment — arising from maintenance, outages, or planned shutdown;
(e) Emergency Curtailment — arising from sudden contingencies requiring immediate intervention.
(2) Each curtailment event shall be tagged with a unique event ID and time-stamped.
2. Mandatory Reasoned Instruction Requirements
Every curtailment or backing down instruction shall comply with Regulation 6 and shall mandatorily include:
(a) event classification;
(b) exact technical trigger;
(c) affected entity or group;
(d) quantum and duration;
(e) alternative measures evaluated;
(f) identification of whether RE or BESS is affected;
(g) attribution category — operational or transmission constraint.
3. Renewable Energy (RE) Curtailment Protocol
(1) RE generators categorized as must-run shall not be curtailed except for grid security reasons.
(2) Where RE curtailment occurs:
(a) SLDC shall demonstrate inevitability;
(b) corridor-specific constraint must be recorded;
(c) non-discriminatory treatment across similarly placed generators shall be ensured.
(3) Curtailment attributable to transmission inadequacy shall be recorded as transmission constraint under Regulation 14.
(4) RE curtailment shall be separately aggregated for reporting and audit.
4. BESS (Battery Energy Storage System) Operational Separation
(1) Battery Energy Storage Systems shall not be treated as must-run resources.
(2) BESS operation shall be governed by:
(a) Round Trip Efficiency (RTE);
(b) Annual Availability Factor (AAF);
(c) dispatch instructions for peak management.
(3) Curtailment of charging or discharging of BESS shall not be treated as RE curtailment.192
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
(4) Any co-located RE+BESS system shall maintain separate metering and scheduling.
(5) SLDC shall ensure that BESS is not used to artificially influence RE scheduling or evade curtailment
classification.
BESS operation shall also be subject to any specific Regulations notified by the Commission for energy storage
resources.
5. Anti-Gaming Safeguards
(1) The following practices shall be treated as potential gaming:
(a) artificial shifting of RE generation through storage to avoid curtailment;
(b) misclassification of BESS discharge as RE injection;
(c) selective curtailment without uniform criteria.
(2) SLDC shall record and flag such instances in the event log.
(3) The Commission may initiate proceedings based on such records.
6. Accountability Attribution Matrix
Responsibility for curtailment shall be attributed as follows:
(a) SLDC — where action is unreasoned, discriminatory, or not supported by records;
(b) STU / Transmission Licensee — where curtailment arises from infrastructure constraints;
(c) Generator / User — where non-compliance with scheduling or technical norms;
(d) Force majeure — where event is beyond control of all parties.
7. Documentation and Audit Requirements
(1) Each curtailment event shall be supported by:
(a) SCADA/EMS data;
(b) voice logs;
(c) switching records;
(d) system conditions snapshot.
(2) All such records shall be auditable and retained as per Regulation 8.
(3) Event-wise audit trails shall be made available to the Commission upon request.
8. Reporting Format Linkage
All curtailment events shall be reported in the formats specified in Annexure IV, including:
(a) event classification;
(b) entity-wise impact;
(c) energy curtailed;
(d) cause attribution;
(e) corrective action taken.
ANNEXURE III
Technical, Metering, Data Acquisition and Validation Standards
(Refer Regulations 6, 7, 8, 11A and related provisions)
This Annexure specifies the technical, metering, data acquisition, communication, validation and audit standards to
be followed by the State Load Dispatch Centre (SLDC) and all grid-connected entities, including specific provisions
for separation of Renewable Energy (RE) and Battery Energy Storage Systems (BESS), to ensure accuracy,
transparency, traceability and regulatory compliance.June 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 193
1. Metering Architecture and Separation Requirements
(1) All grid-connected entities shall install and maintain ABT-compliant meters in accordance with CEA Metering
Regulations.
(2) In case of co-located RE and BESS systems:
(a) Separate meters shall be installed for:
(i) RE generation (gross);
(ii) BESS charging;
(iii) BESS discharging;
(iv) net export/import at interconnection point.
(b) Energy flows shall be distinguishable at all times.
(3) No commingling of RE and BESS energy accounting shall be permitted.
(4) Metering scheme shall be approved by SLDC prior to commissioning.
2. Data Acquisition and SCADA/EMS Integration
(1) All entities shall provide real-time data to SLDC through SCADA/EMS systems.
(2) Data shall include:
(a) MW, MWh, voltage, frequency;
(b) status of generators, feeders and breakers;
(c) BESS state of charge (SoC) and operational status.
(3) Data refresh rate shall not exceed 15 seconds for critical parameters of existing installations and shall be
4 seconds for all new installations and for existing installations upon upgradation, within a period of twentyfour
(24) months from the commencement of these Regulations. The Commission may specify intermediate milestones
through Practice Directions.
(4) Redundant communication channels shall be provided.
3. Data Validation and Time Synchronization:
(1) All data shall be time-synchronised using GPS-based or equivalent time reference.
(2) SLDC shall implement automated validation checks including:
(a) range validation;
(b) consistency checks;
(c) missing data flags.
(3) Discrepancies shall be flagged and corrected with audit trail.
4. Data Logging and Retention
(1) All operational data shall be logged automatically.
(2) Logs shall include:
(a) SCADA data;
(b) reasoned instructions;
(c) curtailment events;
(d) system disturbances.
(3) Data shall be retained for minimum 7 years or longer if required.
5. BESS-Specific Measurement Requirements
(1) BESS shall provide separate telemetry for:
(a) charging power;
(b) discharging power;194
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
(c) state of charge (SoC);
(d) round-trip efficiency (RTE).
(2) BESS shall not mask RE variability.
(3) All BESS operations shall be traceable independently.
6. Cyber security and Data Integrity
(1) All systems shall comply with cyber security guidelines issued by the Government of India.
(2) Data shall be protected against tampering and unauthorized access.
(3) SLDC shall maintain audit logs for all data modifications.
7. Testing, Calibration and Compliance
(1) Meters shall be tested and calibrated periodically.
(2) SLDC may conduct audits and inspections.
(3) Non-compliance shall attract regulatory action.
8. Integration with Reporting Framework
(1) All data shall feed into reporting formats specified in Annexure IV.
(2) Data integrity shall be certified by SLDC.
(3) Reports shall be generated in automated and auditable format.June 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 195
ANNEXURE IV
Standard Reporting Formats and Templates for SLDC Compliance
(Refer Regulations 8, 9, 11, 11A and Annexures II & III)
This Annexure prescribes the mandatory reporting formats to be used by the State Load Dispatch Centre
(SLDC) for ensuring uniform, transparent and auditable reporting of operational events, curtailment, constraints,
and compliance with Commission directions.
Instructions for filling the formats under Annexure IV
(1) The formats specified in this Annexure shall be used by the State Load Dispatch Centre (SLDC) for preparation
of the logs, reports and returns required under Regulations 8, 9, 11, 12 and other applicable provisions of these
Regulations.
(2) All entries shall be made in clear and legible form in ink or in electronic form through the approved reporting
system. Where reports are generated from digital systems, the SLDC shall ensure that the formats prescribed in
this Annexure are replicated in substance, with at least the fields specified herein.
(3) Units shall be recorded as follows, unless otherwise specified in a particular format:
(a) instantaneous or scheduled power in Megawatts (MW);
(b) energy over a period in Megawatt-hours (MWh); and
(c) aggregated energy for monthly or longer-period reports in Million Units (MU), duly indicating both MWh
and MU where appropriate.
(4) Time shall be recorded in a 24-hour clock, with time blocks identified consistently with the Tamil Nadu Electricity
Grid Code and applicable Deviation Settlement and Forecasting & Scheduling Regulations.
(5) Where information relating to multiple categories (for example, wind, solar, conventional and BESS) is required,
the SLDC shall record category-wise data in separate rows or sections, as practicable, so as to permit verification
of category-wise treatment, including for must-run stations.
(6) Where generator-wise, feeder-wise or entity-wise information is not directly available with the SLDC in real
time, the SLDC shall record the information available within its operational domain, and the concerned Qualified
Coordinating Agency (QCA), Distribution Licensee or generating entity shall furnish the remaining details within
the timelines specified in these Regulations.
(7) The SLDC may, with prior intimation to the Commission, introduce additional sub-fields or notes in these
formats to capture relevant technical particulars, provided that such additions do not dilute or omit any field
prescribed in this Annexure.
Curtailment and Congestion Reporting Formats
Format 1: Curtailment and Backing Down Log
.oN
.lS
etaD
)dne–trats(
kcolb emiT
/
noitats
gnilooP
/ eman ytitnE remusnoC
/
raloS
/
dniW( yrogetaC
)rehtO
/
SSEB
/ lanoitnevnoC
)oN
/ seY( nur tsuM
/ noitatsbuS
/ yaB / redeeF rodirroC
tnemliatruc
erofeb eludehcS )hWM / WM(
lautca
/
eludehcs
desiveR
/
WM(
mutnauq
dettimrep )hWM
deliatruc
ygrene
detamitsE )UM / hWM(
)feirb(
tnemliatruc
rof nosaeR
noitareneg(
yrogetac tnevE
/
noitsegnoc
/ gnicnalab
egatlov
/ eruliaf
noissimsnart
noitarepo
noitcetorp
/ eussi
evreser
/ ecnanetniam
/
/ eruejam
ecrof
/ tnemeriuqer )rehto
deredisnoc
serusaem
evitanretlA
)noitpircsed
feirb – N/Y(
detautis
ylralimis
rehtehW
– N/Y(
ekila
detaert seititne )skramer
fo
rennam
dna
emit noitarotseR noitarotser
ot
ecnerefer
gnidulcni(
skrameR
)yna
fi
,sisylana
tneve tsop196
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
Format 2: Monthly Curtailment Summary
Month and year: ____________________
Sl. Entity / Category Must Number of Total Maximum Total Primary Remarks
No. Pooling (Wind / run curtailment curtailed single curtailed reasons (including
station / Solar / (Yes events in energy event duration (top three any
Consumer Conventional / No) the month (MWh / curtailed (hours) categories) recurring
/ BESS / MU) quantum pattern)
Other) (MWh /
MU)
Format 2A: Corridor-wise Curtailment Summary
Sl. Corridor / Category of flows Number of Total curtailed Total Primary Remarks
No. Substation predominantly curtailment energy curtailed reasons
affected (Wind events (MWh / MU) duration
/ Solar / (hours)
Conventional
/ Mixed)
Format 3: Congestion and Transmission Constraint Log
.oN
.lS
etaD
)dne–trats(
kcolb
emiT
/ eniL
/ rodirroC
noitatsbuS
/
remrofsnarT
noitsegnoc
fo noitceriD
)htob
/ tropxe
/ tropmi(
gnidaol
mumixaM
)yticapac
detar
fo
%(
lamreht(
yrogetaC
egatlov
/ daolrevo
timil
ytilibats
/ tniartsnoc )rehto
/
seititne
detceffA
daol /
noitareneg
/
laidemer
etaidemmI
nekat
serusaem
,tnemliatruc
gnidulcni(
)gnihctiws
,gniludehcser deliatruc
detamitsE
ot
eud ygrene
)UM
/ hWM(
noitsegnoc
si
tniartsnoc
rehtehW
)oN / seY(
gnirrucer
rehtehw
,gnirrucer
fI
dna UTS
ot defiiton
ecnerefer(
noissimmoC
dna
41 noitalugeR
ot
)noitacinummoc
51
gnidulcni(
skrameR
,noitagitim
desoporp )elbaliava
fi
Format 4: Event Log (Extract for Reporting)
Event ID Timestamp Event Type Description Operator Outcome Supporting
Action Data Ref
Format 5: Must Run (RE) Curtailment Report
Period covered: (Monthly / Quarterly) ____________________
.oN
.lS
noitats
gnilooP
/ rotareneG eman
raloS
/ dniW(
ygolonhceT )ER rehtO
/
rep
sa( sutats
nur
tsuM
)edoC
dirG
/ noissimmoC
stneve
tnemliatruc
fo rebmuN
doirep
eht gnirud
ygrene
deliatruc
latoT
)UM / hWM(
deliatruc
tneve
elgnis
mumixaM
)UM
/ hWM(
mutnauq
snosaer
yramirP
)seirogetac
level metsys(
noitatsbus
/ rodirroC
devlovni
yltnanimoderp
defiitrec
tnemliatruc
rehtehW
dirg
rof elbadiovanu
sa
)oN /
seY( ytiruces
evitcirtser
ssel rehtehW
seY(
deredisnoc
sevitanretla
)sliated
feirb –
oN
/
tnemliatruc
rehtehW
noissimsnart
ot elbatubirtta
)oN
/
seY(
stniartsnoc
metsys
ot ecnerefer
,seY
fI
tniartsnoc
metsys
noissimsnart
noitalugeR
rednu
noitacfiiton 51
/
41
ecnerefer
gnidulcni(
skrameR
sisylana
tneve tsop
ot
)yna
fi ,stroperJune 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 197
Note: The Must Run (RE) Curtailment Report shall form part of the quarterly compliance report under
Regulation 11.2.
Format 6: Quarterly Compliance Report
Non-
Major Recurring Action
Quarter Total Events Compliance Status
Incidents Constraints Taken
Cases
— — — — — — —
— — — — — — —
— — — — — — —
Format 7: Recurring Constraint Notification
Constraint Energy Affected Suggested
Asset Frequency Duration
ID Impact Entities Mitigation
— — — — — — —
— — — — — — —
— — — — — — —
Format 8: Digital System Implementation Status
Status
Module (Implemented/In Completion Date Issues Remarks
Progress)
— — — — —
— — — — —
— — — — —
Annexure V – Schedule of Harmonised Timelines for Compliance by SLDC and Other Entities
Reference
Sl. Responsible Nature of
Activity / obligation Regulation / Timeline / outer limit
No. entity timeline
Format
1 Reduction of oral emergency Regulation SLDC Within the close of the shift Event based
directions to written 6.1(2) during which the direction
/ electronic reasoned was issued or within four
instructions (4) hours from the time of
issue, whichever is earlier
2 Completion of consolidated Regulation SLDC Within four (4) hours from Event based
post event log for cascading 6.1(4) restoration of normal grid
disturbances / widespread conditions or by the end
grid events of the full shift immediately
following such restoration,
whichever is later, subject
to a maximum of eight (8)
hours from restoration; in
exceptional cases, within
twenty four (24) hours
with interim updates not
exceeding eight (8) hours198
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
Reference
Sl. Responsible Nature of
Activity / obligation Regulation / Timeline / outer limit
No. entity timeline
Format
3 Implementation of digital Regulations SLDC Within eighteen (18) One time (with
reasoned instruction module 6.1A, 6.1B, months from the date of subsequent
and associated digital 11A(1) commencement of these upgrades as
systems (automated logging, Regulations, or such required)
reporting, curtailment tracking) extended period as may be
allowed by the Commission
for justified reasons
4 Submission of digital Regulations SLDC Within three (3) months One time
systems implementation 6.1B(2), from the date of
plan (architecture, timelines, 11A(3) commencement of these
resources) Regulations
5 Digitisation of manual records Regulation SLDC Within seventy two (72) Event based
where electronic systems are 8.1 (proviso) hours of restoration of
temporarily unavailable electronic systems
6 Updating of curtailment log Regulation SLDC Contemporaneously during Event based
for each curtailment event 9.3 the shift in which the
curtailment occurs and, in
all cases, not later than the
end of the shift immediately
following the shift in which
such curtailment occurred
7 Provision of feeder / bay Regulation QCA / Within seven (7) days from Event based
level implementation details 9.1(d) generating the date of instruction,
for curtailment instructions (proviso) entity where such details were not
available with SLDC in real
time
8 Advance communication of Regulation SLDC At least one (1) day in Event based
planned curtailment due to 9.4(a) advance of implementation
maintenance, outages or
scheduled shutdown
9 Communication of emergency Regulation SLDC As soon as practicable Event based
curtailment due to sudden 9.4(b) and, in any case, not later
contingencies than fifteen (15) minutes
before implementation,
or immediately after
implementation where
prior communication is
not possible, with reasons
recorded in the event log
10 Completion of post event Regulation SLDC Within seven (7) days from Event based
analysis for large scale 12.1 the date of the event
curtailment, repeated backing
down, islanding, major
voltage violation, prolonged
congestion or system
disturbance
11 Submission of post event Regulation SLDC Along with completion Event based
analysis to Commission and 12.3 of the analysis under
affected entities Regulation 12.1 (within
seven (7) days), or within
such time as may be
specified by the Commission
in particular casesJune 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 199
Reference
Sl. Responsible Nature of
Activity / obligation Regulation / Timeline / outer limit
No. entity timeline
Format
12 Monthly publication of Regulation SLDC Within thirty (30) days from Recurring
curtailment and operational 11.1 and the end of each month (monthly)
report on SLDC website and 11.4
submission to Commission
13 Quarterly compliance report Regulation SLDC Within thirty (30) days from Recurring
to Commission 11.2 the end of each quarter (quarterly)
14 Provision of generator wise Regulation QCA / Within such time as may Event based /
or feeder wise curtailment 11.4 Distribution be specified by the SLDC recurring
and operational data to (proviso) Licensee / in its communication, which
SLDC where not available in generating shall not be less than
real time entity seven (7) days, unless
otherwise directed by the
Commission
15 Communication of major Regulation SLDC As soon as practicable, and Event based
congestion, power transformer 11.5 in any case within one (1)
breakdown or significant grid hour of identification of the
event to affected HT / EHT event
entities through website or
designated portal
16 Preservation of logs and Regulation SLDC For not less than seven Ongoing
records 8.2 (7) years, and, where
records are relevant to any
pending proceedings, until
final resolution of such
proceedings
17 Completion of institutional Regulation Commission Within six (6) months from One time
framework examination for 5.5.5(1) the date of commencement
establishing SLDC as an of these Regulations
independent entity under
Section 31(2)
18 Response of State Regulation State Within three (3) months of One time (per
Government to 5.5.5(4) Government receipt of the Commission’s recommendation)
recommendations for recommendation
establishment of independent
SLDC
19 Discontinuance of common Regulation STU / Within ninety (90) days from One time
executive control over STU 5.5.5(6) SLDC / the date of commencement
and SLDC (same individual State of these Regulations
as CMD / Chairperson) Government,
as
applicable
20 Implementation of workforce Regulation SLDC / Within such period as Phased, as
adequacy in accordance with 18.1 STU (for may be approved by the approved by
Ministry of Power guidelines staffing Commission in the SLDC Commission
support) staffing and ARR orders,
having regard to national
benchmarks (presently
approximately 144 personnel
for a large SLDC)
This Annexure is a consolidated reference of timelines specified in the main body of these Regulations and
is intended for ease of compliance and monitoring. In case of any inconsistency between this Annexure and
the timelines specified in the substantive provisions of these Regulations, the timelines in the main body of the
Regulations shall prevail.
Chennai-600 032, M. SENTHIL KUMAR,
29th May 2026. Secretary,
Tamil Nadu Electricity Regulatory Commission.200
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
Explanatory Statement
1. Statutory basis
1.1 The State Load Dispatch Centre (SLDC) is established under Section 31 of the Electricity Act, 2003 and is
entrusted with the functions specified under Sections 32 and 33 relating to integrated operation of the State power
system, scheduling and dispatch, and supervision and control of intra-State transmission.
1.2 Under Sections 86(1)(h), 86(1)(i), 86(1)(k) and 181 of the Act, the Commission is empowered to specify the
Tamil Nadu Electricity Grid Code, to regulate the operations of the SLDC, and to make regulations governing grid
operation, system coordination, transparency and related matters.
1.3 These Regulations are framed in exercise of the aforesaid statutory powers to specify a structured framework
for the functions, accountability, fees and charges, and institutional safeguards applicable to the SLDC.
2. Regulatory necessity
2.1 The Tamil Nadu Electricity Grid Code and other operational regulations provide the technical and procedural
framework for system operation; however, they do not comprehensively prescribe accountability, documentation, and
transparency standards governing SLDC decisions, nor do they fully address the institutional separation between
the SLDC and the State Transmission Utility (STU).
2.2 The Commission has observed recurring disputes relating to curtailment, congestion, scheduling, and attribution
of responsibility between SLDC, STU and other entities, wherein absence of contemporaneous records, reasoned
instructions, and clear ownership of constraints has impeded effective adjudication and regulatory oversight.
2.3 It is therefore necessary to establish a dedicated regulatory framework that (a) defines the functions and
duties of the SLDC, (b) prescribes minimum standards for logging, reporting and postevent analysis, (c) separates
operational accountability from transmission planning obligations, and (d) provides an enabling structure for
determination of SLDC fees and charges.
3. Core regulatory intent
3.1 These Regulations are intended to:
(a) ensure that all material operational actions of the SLDC are reasoned, recorded, time-stamped and
auditable through electronic logs and supporting data;
(b) establish clear documentation standards, including event logs, curtailment and backing-down logs, congestion
and constraint logs, and structured post-event analyses, supported by standard formats in Annexure IV;
(c) enable traceability of operational decisions to real-time grid conditions and to specific provisions of the
Electricity Act, the Tamil Nadu Electricity Grid Code, applicable TNERC Regulations and Detailed Procedures;
(d) facilitate effective regulatory oversight, dispute resolution and adjudication by ensuring that SLDC actions
are supported by contemporaneous and verifiable evidence; and
(e) delineate responsibility between SLDC and the STU / transmission licensee, particularly in relation to
transmission constraints and recurring bottlenecks, through the framework under Regulations 14 and 15 and
Annexure II.
4. Transparency and evidence-based operation
4.1 The Regulations mandate issuance of reasoned instructions for all material operational interventions, including
backing down, curtailment, load shedding, congestion management and comparable actions, with strict timelines
for reducing oral instructions to written or electronic form and for preparing consolidated post-event logs.
4.2 Mandatory maintenance of digital logs, backed by SCADA/EMS data, voice logs and other records, ensures that
SLDC actions are verifiable, time-synchronised and supported by contemporaneous evidence for each curtailment
event or system disturbance.
4.3 The provisions relating to accountability and adverse inference are designed to discourage reliance on
generic or aggregated explanations in proceedings before the Commission and to promote a culture of speaking,
evidence-based system operation.
5. Responsibility attribution and institutional independence
5.1 The Regulations clearly distinguish between operational actions of the SLDC and infrastructural constraintsJune 17, 2026] TAMIL NADU GOVERNMENT GAZETTE 201
attributable to the STU or transmission licensees, and require identification and reporting of recurring constraints,
transmission bottlenecks and augmentation needs through a dedicated framework under Regulations 14 and 15.
5.2 Institutional safeguards are provided to ensure that the SLDC functions independently and neutrally, in
accordance with Section 31(2) of the Act, and is not subject to operational direction or common executive control
by the STU or any commercial entity, including a timebound roadmap for examining establishment of the SLDC
as a separate entity.
5.3 This distinction and institutional separation are necessary to preserve the neutrality and integrity of system
operation, to avoid misattribution of responsibility, and to support a transparent basis for determination of SLDC
fees and charges.
6. Renewable energy and storage integration
6.1 Renewable energy generating stations are recognised as must-run, subject only to recorded gridsecurity
considerations, consistent with the Tamil Nadu Electricity Grid Code and applicable TNERC Regulations on
Forecasting, Scheduling and Deviation Settlement.
6.2 With increasing deployment of Battery Energy Storage Systems (BESS), these Regulations provide for separation
of metering, scheduling, telemetry and accounting of renewable energy and BESS, prevention of commingling
of energy, and safeguards against gaming and misclassification, as elaborated in Annexure II and Annexure III.
6.3 BESS operations are treated as flexibility resources governed by efficiency, availability and dispatch instructions,
and are distinct from must-run obligations applicable to renewable energy, thereby enabling transparent curtailment
reporting and accurate assignment of commercial consequences.
7. Digital compliance framework and reporting
7.1 The Regulations mandate adoption of digital systems for reasoned instructions, logging, curtailment tracking,
and reporting, including implementation of a digital reasoned instruction module integrated with the scheduling
and SCADA/EMS platforms within specified timelines, supported by transitional hybrid manualdigital arrangements
during the implementation period.
7.2 Standard reporting formats and templates in Annexure IV, read with the harmonised timelines in the Schedule
of Timelines (Annexure V), provide a uniform structure for monthly and quarterly reporting, must-run curtailment
summaries, recurringconstraint notifications, and digital implementation status reports, thereby facilitating monitoring
by the Commission and access to information by stakeholders.
8. SLDC fees, charges and workforce adequacy
8.1 The Regulations recognise “Annual SLDC Charges” as an aggregate revenue requirement framework for the
SLDC, aligned with the Annual LDC Charges model adopted at the central level, and provide for a dedicated set
of Regulations on determination, recovery and sharing of SLDC fees and charges.
8.2 The provisions on staffing and workforce adequacy require the SLDC to progressively align its manpower
strength and skill mix with the Ministry of Power’s Workforce Adequacy Guidelines for Load Despatch Centres, so
that the enhanced logging, analysis and reporting obligations are matched by appropriate capacity and resources.
9. Expected regulatory outcomes
9.1 The Regulations are expected to:
(a) enhance transparency, neutrality and accountability of system operation;
(b) reduce disputes and litigation arising from curtailment, congestion and scheduling decisions by ensuring
availability of even-twise records;
(c) improve grid discipline and compliance with the Tamil Nadu Electricity Grid Code and related Regulations;
(d) strengthen regulatory oversight and targeted network planning by clearly attributing operational and
infrastructural responsibilities; and
(e) support reliable, secure and economic operation of the State grid, including effective integration of renewable
energy and storage resources.202
TAMIL NADU GOVERNMENT GAZETTE [Part VI—Sec. 2
10. Conclusion
10.1 The Commission considers it necessary to notify these Regulations in public interest to ensure that the SLDC
discharges its statutory functions in a transparent, accountable, evidence-based and non-discriminatory manner,
with clear separation of its operational role from transmission planning obligations.
10.2 These Regulations are intended to supplement the Tamil Nadu Electricity Grid Code and other applicable
Regulations, and to strengthen the governance of system operation and SLDC economics, without diluting the
operational flexibility required for real-time grid management and restoration.
Chennai-600 032, M. SENTHIL KUMAR,
29th May 2026. Secretary,
Tamil Nadu Electricity Regulatory Commission.
PRINTED AND PUBLISHED BY THE DIRECTOR OF STATIONERY AND PRINTING, CHENNAI
ON BEHALF OF THE GOVERNMENT OF TAMIL NADU