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© [Regd. No. TN/CCN/467/2012-14.
GOVERNMENT OF TAMIL NADU [R. Dis. No. 197/2009.
2025 [Price: Re. 7.20 Paise.
TAMIL NADU
GOVERNMENT GAZETTE
PUBLISHED BY AUTHORITY
No. 3] CHENNAI, WEDNESDAY, JANUARY 22, 2025
Thai 9, Kurothi, Thiruvalluvar Aandu–2056
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
The Tamil Nadu Electricity Regulatory Commission (Deviation Settlement Mechanism 2-18
and related matters) (Amendment) Regulations, 2024. .. .. .. ..
DTP—VI-2 (3) [1]2 TAMIL NADU GOVERN MENT GAZETTE [Part VI—Sec. 2
NOTIFICATIONS BY HEADS OF DEPARTMENTS, ETC.
TAMIL NADU ELECTRICITY REULATORY COMMISSION CHENNAI.
The Tamil Nadu Electricity Regulatory Commission (Deviation Settlement Mechanism and related matters)
(Amendment) Regulations, 2024.
(Notification No. TNERC/DSM&RM/22-3, dt. 27-12-2024)
(Lr.No. TNERC/Legal/1366/D.No.1859/2024)
No.VI(2)/1/2025.
In exercise of the powers conferred by Sections 86(1) and 181(2)(zp) read with Sections 32 and 33 of the Electricity
Act, 2003 (Central Act 36 of 2003) and all other powers enabling it in this behalf, the Tamil Nadu Electricity Regulatory
Commission hereby makes the following amendments to the Tamil Nadu Electricity Regulatory Commission (Deviation
settlement mechanism and related matters) Regulations, 2019 (hereafter referred to as “the Principal Regulations”) and
the draft of the same having been previously published as required by sub-section (3) of section 181 of the said Act:
Amendments
(i) These Regulations may be called as the “Tamil Nadu Electricity Regulatory Commission (Deviation settlement
mechanism and related matters) (Amendment) Regulations, 2024”.
(ii) These Regulations shall come into force from the date of publication in the Tamil Nadu Government Gazette except for
Sub-clauses (2) and (3) in clause (A) of Regulation 10 of these Regulations pertaining to removal of cap rate which shall
come into force from 01-04-2024 as ordered by the Commission in its Order No. 1 of 2024, dated 22-01-2024 and Order
dated 13-08-2024 in M.P. No. 22 of 2024.
2. Amendment to the Regulation 4 of the Principal Regulations:
In the principal Regulations, in Regulation 4, the sub-regulations (1) and (2) shall be substituted as follows:
“(1) These Regulations shall be applicable to all buyer(s) and seller(s) involved in the transactions of conveyance of
electricity facilitated through Open Access using intra-state transmission system and/or distribution system of electricity
(including inter-state wheeling of power), subject to the following conditions:
(a) Deviation Settlement Mechanism under this Regulation shall be applicable to all seller(s) including Open Access
Generating Station(s), State owned Generating Station(s), but excluding wind, solar and State owned hydro
Generating Station(s) including run of river projects connected to intra-state transmission system or distribution
system and
(b) Deviation Settlement Mechanism under this Regulation shall be applicable to all buyers i.e. Distribution
Licensee(s), deemed Distribution Licensee(s) and full Open Access Consumers connected to intra-state
transmission system or distribution system;
Provided that these Regulations shall be made applicable to all Open Access consumers connected to the
intra-state transmission system or distribution system on later date as may be notified by the Commission.”
3. Amendment to the Regulation 6 of the Principal Regulations:
(i) In the principal Regulations, in Regulation 6, in sub-regulation (5), the expression (1) shall be re-numbered as (6).
4. Amendment to the Regulation 7 of the Principal Regulations:
(i) In the principal Regulations, in Regulation 7, in sub-regulation (1), the clause (C) shall be substituted as follows:
“Operating Range of Frequency: The normal operating range for average grid frequency for time block shall be in line
with range stipulated under IEGC from time to time and no deviation shall be allowed beyond such operating range of
frequency.
Note:- The system frequency = f and f = [49.90 Hz < f < 50.05 Hz] and this frequency band shall be applied in this
band
Regulation, wherever applicable;”Jan. 22, 2025] TAMIL NADU GOVERNMENT GAZETTE 3
(ii) In the principal Regulations, in Regulation 7, in sub-regulation (1), the clause (E) shall be substituted as follows:
“Settlement Period: Preparation and settlement of ‘State Deviation Pool Accounts’ shall be undertaken on weekly basis
and the same shall be published in the website of the SLDC on weekly basis;”
(iii) In the principal Regulations, in Regulation 7, in sub-regulation (1), the clause (I) shall be substituted as follows:
“Premise for Allocation of Losses: For scheduling purpose, the transmission and distribution losses as specified in the
Commission’s tariff order issued from time to time shall be made applicable amongst the State Entities to the scheduled
drawal by each State Entity in the respective time block.
Provided that the SLDC shall maintain accounts of actual intra-state transmission system losses of each time block and
publish on its website;”
5. Amendment to Regulation 9 of the Principal Regulations:
(i) In the principal Regulations, in Regulation 9, the sub-regulation (2) shall be substituted as follows:
“If in the proceeding initiated by the Commission or in the enquiry made in this regard under sub regulation (1), it is proved
that any seller or any Buyer has indulged in gaming, the Commission may without prejudice to any other action under the
Act or Regulation made there under, levy penal charges for deviation to such seller or buyer during the period of such
gaming.
(ii) In the principal Regulations, in Regulation 9, after sub-regulation (2) and the entries relating thereto, the following
sub-regulation shall be inserted, namely;-
“(3) Notwithstanding to the sub-regulations (1) and (2), the generating company may be required to demonstrate the
declared capability of its generating station as and when asked by the SLDC. In the event of generator failing to demonstrate
the declared capability, the SLDC may initiate proceedings against such generator by filing appropriate petition before the
Commission as specified in the sub-regulation (1).”
6. Amendment to Regulation 10 of the Principal Regulations:
(i) In the principal Regulations, in Regulation 10, in clause (A), the sub-clause (1) shall be substituted as follows:
“The charges for the Deviations for all the time-blocks shall be payable for over-drawal by the Buyer and under-injection by
the Seller and receivable for under-drawal by the Buyer and over-injection by the Seller, which are State Entities, and shall
be worked out on the average frequency of a time-block by considering the Price Vector for Deviation Charges as specified
in the Annexure-1 of these Regulations and subject to conditions stipulated under clause (2) to (7) of this regulation:
Provided the seller/buyer shall stick on to their schedule at each time block and any deviation shall not exist for more than
6 continuous blocks i.e. a change in sign of the deviation shall be made once every 6 time blocks, failing which additional
charges @ 20% over and above the deviation charges applicable shall be levied for the duration of continuance of violation
i.e. from 7th block;
Provided further that the applicability of above prescribed additional charges for such failure by seller(s) / buyer(s) shall be
applicable from the date of notification of this amendment.”
(ii) In the principal Regulations, in Regulation 10, in clause (A), the sub-clauses (2) and (3) shall be omitted.
(iii) In the principal Regulations, in Regulation 10, in clause (A), the sub-clause (9) shall be substituted as follows:
“The charges for deviation by way of injection of infirm power prior to COD shall be zero”4 TAMIL NADU GOVERN MENT GAZETTE [Part VI—Sec. 2
7. Amendment to Regulation 11 of the Principal Regulations:
(i) In the principal Regulations, in Regulation 11, the Proviso to clause (A) shall be substituted as follows:
“Provided that the total deviation from schedule in energy terms during a day shall not be in excess of 3% of the total
schedule for the drawee entities and 1% for the generators and additional charge of 20% over and above the daily base
DSM payable / receivable shall be applicable in case of said violation and this additional charge is in addition to the penalty
for gaming as prescribed in the sub-regulation 2 of regulation 9;”
(ii) In the principal Regulations, in Regulation 11, the proviso to clause (B) shall be substituted as follows:
“Provided that no over-drawal of electricity by any Buyer and under-injection of electricity by the seller shall be permissible
when the grid frequency is “below 49.90” and no under-drawal of electricity by any Buyer and over-injection of electricity by
the seller shall be permissible when grid frequency is “50.05 Hz and above;”
(iii) In the principal Regulations, in Regulation 11, the clause (D) shall be substituted as follows:
“In addition to Charges for Deviation as stipulated under Regulation 10 of these Regulations, Additional Charge for
Deviation shall be applicable for over-drawal as well as under-injection of electricity for each time block in excess of the
volume limit specified in Clause (B) and (C) of this regulation when average grid frequency of the time block is “49.90 Hz
and above” at the rates specified in the Table I of Annexure II in accordance with the methodology specified in clause (M)
of this regulation;”
(iv) In the principal Regulations, in Regulation 11, the clause (E) shall be substituted as follows:
“Additional charge for deviation for under-injection of electricity shall be the same to all type of sellers irrespective of the
fuel type and whether the tariff of such generating station is regulated by the Commission or not;”
(v) In the principal Regulations, in Regulation 11, the proviso clause to the clause (L) shall be omitted.
(vi) In the principal Regulations, in Regulation 11, the clause (M) shall be substituted as follows:
“The Additional Charge for Deviation for over-drawals and under-injection of electricity for each time block in excess of the
volume limit specified in clause (B) and (C) of this Regulation when grid frequency is “49.90 Hz and above” shall be levied
as per the Table–I of Annexure –II of this Regulation. This additional charge shall be levied over and above the deviation
charges as specified in the Annexure – I & III of this Regulation;”
(vii) In the principal Regulations, in Regulation 11, the clause (N) shall be substituted as follows:
“The additional Charge for Deviation for over-drawals and under-injection of electricity for each time block when grid
frequency is “below 49.90 Hz” shall be equivalent to 100% of Charge for Deviation corresponding to average grid
frequency of the time-block. This additional charge shall be levied over and above the deviation charges as specified in the
Annexure – I & III of this Regulation;”
(viii) In the principal Regulations, in Regulation 11, the clause (O) shall be omitted.
(ix) In the principal Regulations, in Regulation 11, the clause (Q) shall be substituted as follows:
“The additional charges @ 20% of the deviation charges applicable on daily base DSM payable/receivable as the case
may be shall be levied for the duration of continuance of violation of sign change stipulation for each such violation during
a day from the date of notification of this amendment.
To illustrate, the change of sign should take place at least once after every six time blocks. Accordingly, the entity, starting
from time block t1, should change the sign after time block t6. In case, sign change does not take place immediately in
block t7, but takes place from time block t8 upto time block t12, additional charge shall be levied equivalent to one violation.Jan. 22, 2025] TAMIL NADU GOVERNMENT GAZETTE 5
In case, sign change does not take place immediately after time block t12 i.e. in block t13, but takes place from time block
t14 upto time block t18, additional charge shall be levied equivalent to two violation;.”
(x) In the principal Regulations, in Regulation 11, the clause (T) shall be substituted as follows:
“The State Load Despatch Centre shall, on weekly basis, prepare and publish on its website the records of the Deviation
Accounts, specifying the quantum of over-drawal/ under-injection and corresponding amount of Charges for Deviation
payable/receivable for each Buyer and Seller.”
8. Amendment to Regulation 13 of the Principal Regulations:
(i) In the principal Regulations, in Regulation 13, in sub-regulation (2), the clause (iii) shall be substituted as follows:
“The State entities shall comply with statutory requirements for payment of applicable statutory levies, if any;”
9. Amendment to Regulation 14 of the Principal Regulations:
(i) In the principal Regulations, in Regulation 14, the sub-regulation (2) shall be substituted as follows:
“If payments against the Charges for Deviation including Additional Charges for Deviation are delayed by more than two
days, i.e., beyond twelve (12) days from the date of issue of the statement by the SLDC, the defaulting constituent shall
have to pay simple interest @ 0.06% for each day of delay and the same may be added in the energy bill, if such facility
is available, of such defaulting constituent by the Distribution Licensee on receipt of information of such default from the
SLDC. This is without prejudice to any action that may be taken under Section 142 of the Act in addition to any action under
Section 56 of the Act and other relevant Regulations.”
10. Amendment to Annexure-I of the Principal Regulations:
(i) In the principal Regulations, in the Annexure-I, the clause (1) shall be substituted as follows:
“1) As specified in the Regulation 10(A) of these Regulations, the charges for the Deviations for all the time-blocks shall be
payable for over-drawal by the Buyer and under-injection by the Seller and receivable for under-drawal by the Buyer and
over-injection by the Seller, which are State Entities, and shall be worked out on the average frequency of a time-block by
considering the Price Vector for Deviation Charges as specified in the following table:
Average frequency of time Charges for deviation
block (Hz)
Below Not below (paise/kwh)
50.05 0.0
50.05 50.04
50.04 50.03 Slope determined by joining the price at not below 50.05 Hz and identified price at 50.00
50.03 50.02 Hz and as detailed in the note below of this Regulation.
50.02 50.01
50.01 50.00 Where P is the Weighted average Area Clearing Price in paisa per kWh discovered in the
Day Ahead Market segments of all the power exchanges6 TAMIL NADU GOVERN MENT GAZETTE [Part VI—Sec. 2
50.00 49.99
49.99 49.98
49.98 49.97
49.97 49.96
49.96 49.95 Slope determined by joining the price identified at 50.00 Hz and price at below 49.90 Hz
49.95 49.94 and as detailed in the note below of this Regulation.
49.94 49.93
49.93 49.92
49.92 49.91
49.91 49.90
49.90 1000.00
(ii) In the principal Regulations, in the Annexure-I, in clause (1), the sub-clause (vi) shall be omitted.
11. Amendment to Annexure-II of the Principal Regulations:
(i) In the principal Regulations, in the Annexure-II, the Table-II shall be omitted.
12. Amendment to Annexure-III of the Principal Regulations:
(i) In the principal Regulations, the Annexure-III shall be substituted as follows:
“Illustration to the DSM price vector:
Average frequency of the time block (Hz)
Charges for deviation (Paise/kWh)
Below Not below
50.05 0.00
50.05 50.04 1 X P/5
50.04 50.03 2 X P/5
50.03 50.02 3 X P/5
50.02 50.01 4 X P/5
50.01 50.00 P
50.00 49.99 90.909 + 10 X P/11
49.99 49.98 181.818 + 9 X P/11
49.98 49.97 272.727 + 8 X P/11
49.97 49.96 363.636 + 7 X P/11
49.96 49.95 454.545 + 6 X P/11
49.95 49.94 545.454 + 5 X P/11
49.94 49.93 636.363 + 4 X P/11
49.93 49.92 727.272 + 3 X P/11
49.92 49.91 818.181 + 2 X P/11
49.91 49.90 909.090 + 1 X P/11
49.90 1000.00
Where P is the Weighted average Area Clearing Price in paisa per kWh discovered in the Day Ahead Market segments
of all the power exchanges.”Jan. 22, 2025] TAMIL NADU GOVERNMENT GAZETTE 7
13. General Amendments:
(i) In the Principal Regulations, for the expression “49.85 Hz” wherever it occurs, the expression “49.90 Hz” shall be
substituted.
(By order of the Tamil Nadu Electricity Regulatory Commission)
Chennai, C. VEERAMANI,
30th December 2024. Secretary,
Tamil Nadu Electricity Regulatory Commission.
Explanatory Statement
1. The Tamil Nadu Electricity Regulatory Commission (Deviation settlement mechanism and related
matters) Regulations, 2019 was notified by the Commission vide Notification No. TNERC/DSM&RM/22-1,
dated 01-03-2019 and the same was published in the Tamil Nadu Government Gazette on 20-03-2019. The
whole purpose of this Regulation is to bring grid discipline by maintaining the schedule and drawal by the sellers
(conventional generators) and the buyers (excluding direct customers of the Distribution Licensee (including
partial and full open access consumers)) connected to the intra-state transmission system or distribution system.
2. The rising Renewable Energy (RE) penetration and associated uncertainty of generation along with uncertainty of
electricity demand remains a key challenge in ensuring power system stability. Power system stability is influenced
by two critical and dynamic parameters – (i) system frequency and (ii) market prices.
3. To ensure that the Deviation Settlement Mechanism is able to provide appropriate signal to minimize power
system imbalance thus ensuring power system stability, the present amendments are made by imposing penal
actions for the deviations which should have come into force six months after notification of these Regulation but
commenced only on 01-04-2024 since the licensee was not ready in various aspects especially in communicating
and transfer of energy data from the meters. Necessary order was issued by the Commission in this regard vide
Order No. 1 of 2024, dated 22-01-2024.
4. Meanwhile, the Commission in its order dated 13-08-2024 in M.P.No. 22 of 2024 filed by the TANGEDCO has
inter-alia passed the following orders in consultation with the stakeholders concerned:
“……………………… 2.7.2. The charges for deviation as per the TNERC (Deviation Settlement Mechanism and
related matters) Regulations, 2019 is applicable to all the Generators in respect of transactions of conveyance
of electricity through short- term open access or medium-term open access or long-term open access using
intra-State transmission system or distribution system of electricity (including inter-state wheeling of power).
However, the cap rate prescribed in the Regulation 10(A)(2) and 10(A)(3) of TNERC (Deviation Settlement
Mechanism and related matters) Regulations, 2019 is removed and necessary amendment to this effect will be
issued by the Commission in due course.”
5. In view of the above order, this amendment is issued duly considering the interest of all the stakeholders, safe,
secure and reliable operation of the grid. It is also to be stated that the grid separation/failure is reduced drastically
after implementation of inter-state Availability Based Tariff (ABT) in phases during the years 2002-2003 in the
Country. In the similar line, the intra-state deviation settlement mechanism (modified version of intra-state ABT)
will also help the state grid for better performance. By linking DSM with market price, there will be more discipline
in the grid as well as frequency band can be narrowed.
6. Further, it is necessary to remove the cap rate for the charges for deviation of the generating stations as
prescribed in the Regulation 10(A)(2) and 10(A)(3) of TNERC (Deviation Settlement Mechanism and related
matters) Regulations, 2019 in order to protect the interest of the Distribution Licensee and other stakeholders
especially consumers of the Distribution Licensee. DSM interventions have helped utility not only to reduce the
peak electricity demands, but also to defer high investments in generation, transmission and distribution networks.
The reasons for decisions of the Commission for finalising this amendments are given in below:8 TAMIL NADU GOVERN MENT GAZETTE [Part VI—Sec. 2
a. The DISCOM pays the charges for deviations to the Regional Pool Account at the rate prescribed by the
CERC, which does not commensurate with the Cap Rate prescribed in the Regulation 10(A)(2) and 10(A)
(3) of TNERC (Deviation Settlement Mechanism and related matters) Regulations, 2019, viz. 311 paise/unit
(Generating stations for which Commission decides the tariff) and 303.04 paise/unit (Generating stations for
which Commission does not decides the tariff). Whereas, the generators pays only the capped rates, and
the difference between the payment made by the DISCOM for the State deviation and the deviation charges
received by the DISCOM from these State generators have to be borne by the DISCOM only which in turn
falls under the heads of common consumers through tariff hike.
b. The objective definition of “Gaming” should clearly identify the basis for assessing “intentional
misdeclaration” of the schedule. There is a possibility that the Generator may indulge in gaming by
under injecting over his committed schedule since the deviation charges were capped and the consumer
especially captive consumer will get the benefit of adjusting his consumption over scheduled generation
(lesser than the actual injection of power) thereby making undue commercial gain through DSM charges.
Hence, the cap limit for deviation by the generators was removed. Also, there is no cap limit of levy for the
deviation by the generators in respect of inter-state transaction.
7. The Commission in its order No. 1-1 of 2024, dated 20-02-2024 had exempted the Hydro Generating Stations
including the Pumped storage power plant of the TANGEDCO under the purview of the Deviation Settlement
Mechanism notified vide TNERC (Deviation Settlement Mechanism and related matters) Regulations, 2019 since
the hydro generating stations are irrigation linked and are being utilisd as spinning reserve and operated fully as
per the directions of the SLDC. Accordingly, this amendment excludes the hydro generating stations including run
of river hydro projects under the purview of the Deviation Settlement Mechanism.
8. The very objective of these amendments is to maintain grid discipline and grid security as envisaged under the
Tamil Nadu Electricity Grid Code through the commercial mechanism for Deviation Settlement through drawal and
injection of electricity by users of the Grid. Also, Commission is in the process of amending the State Grid Code
to align with the recent developments in the Power market.
9. As per the CERC order dated 31-03-2023 in Petition No. 04/SM/2023 (suo-Motu), the maximum ceiling limit
applicable for daily average ACP discovered in the DAM segment of power exchange at 50.00 Hz shall be
Rs.10/unit. Accordingly, the daily average ACP is revised from Rs.8/unit to Rs.10/unit and modified the DSM price
vector in Annexure-III.
10. Based on the post implementation experiences of these Regulations in the State of Tamil Nadu, the review
of the Tamil Nadu Electricity Regulatory Commission (Deviation Settlement Mechanism and related matters)
Regulations, 2019 to align with the CERC (Deviation Settlement Mechanism and Related Matters) Regulations,
2024 to the extent possible will be undertaken by the Commission as and when necessary duly after consulting
the views of all the stakeholders.
(By order of the Tamil Nadu Electricity Regulatory Commission)
Chennai, C. VEERAMANI,
30th December 2024. Secretary,
Tamil Nadu Electricity Regulatory Commission.Jan. 22, 2025] TAMIL NADU GOVERNMENT GAZETTE 9
Statements showing existing provisions and provisions as amended
Amendment to TNERC (Deviation settlement mechanism and related matters) Regulations, 2019
Sl. Existing Regulation Regulation as amended
No.
1. 1. Short title and commencement 1. Short title and commencement
1. xxx 1. xxx
2. These Regulations except provisions relating to 2. These Regulations shall come into force from the date
commercial arrangements, deviation charges and of publication in the Tamil Nadu Government Gazette
penalty shall come into force on the date of publication except for Sub-clauses (2) and (3) in clause (A) of
of these Regulations in the Tamil Nadu Government Regulation 10 of these Regulations pertaining to removal
Gazette: of cap rate which shall come into force from 01-04-2024
as ordered by the Commission in its Order No. 1 of 2024,
Provided that the provisions relating to Commercial
dated 22-01-2024 and Order dated 13-08-2024 in M.P.
Arrangements and the Deviation Charges and
No. 22 of 2024.
Additional Charge for Deviation and penal actions
if any, shall come into force six months after the
commencement of these Regulations.
2 4. Applicability 4. Applicability
1. These Regulations shall apply to the transactions (1) These Regulations shall be applicable to all buyer(s)
of conveyance of electricity through short- term open and seller(s) involved in the transactions of conveyance
access or medium-term open access or long-term of electricity facilitated through Open Access using
open access using intra-State transmission system or intra-state transmission system and/or distribution
distribution system of electricity (including inter-state system of electricity (including inter-state wheeling of
wheeling of power). power), subject to the following conditions:
2. These Regulations shall be applicable to (a) Deviation Settlement Mechanism under this
Regulation shall be applicable to all seller(s)
(a) all Seller(s) including Open Access Generating
including Open Access Generating Station(s),
Station(s),Generating stations of Distribution
State owned Generating Station(s), but
licensees but excluding Wind and Solar Generating
excluding wind, solar and State owned hydro
Station(s) connected to Intra-state Transmission
Generating Station(s) including run of river
system or Distribution system and .
projects connected to intra-state transmission
(b) all Buyers, excluding full open access consumers, system or distribution system and
partial open access consumers connected to the
(b) Deviation Settlement Mechanism under this
Intra-State Transmission system or Distribution
Regulation shall be applicable to all buyers i.e.
system.
Distribution Licensee(s), deemed Distribution
Licensee(s) and full Open Access Consumers
connected to intra-state transmission system or
distribution system;
Provided that these Regulations shall be made applicable
to all Open Access consumers connected to the
intra-state transmission system or distribution system on
later date as may be notified by the Commission.
3 6. Energy accounting statements 6. Energy accounting statements
(1) to (5) xxx (1) to (5) xxx
(1) A detailed energy accounting procedure shall be (6) A detailed energy accounting procedure shall be
prepared by SLDC and submitted for approval to the prepared by SLDC and submitted for approval to the
Commission: Provided that SLDC shall undertake Commission: Provided that SLDC shall undertake
stakeholder consultation by uploading the Draft stakeholder consultation by uploading the Draft
procedure on SLDC’s website before submission of procedure on SLDC’s website before submission of
procedure to the Commission for approval. procedure to the Commission for approval.10 TAMIL NADU GOVERN MENT GAZETTE [Part VI—Sec. 2
4 7. Principles for operationalising Deviation 7. Principles for operationalising Deviation
Settlement Mechanism Settlement Mechanism
(1) xxx (1) xxx
(A) xxx (A) xxx
(B) xxx (B) xxx
(C) Operating Range for Frequency: The normal (C) Operating Range of Frequency: The normal
operating range for average grid frequency for time operating range for average grid frequency for time block
block shall be in line with range stipulated under shall be in line with range stipulated under IEGC from
IEGC and Tamil Nadu Electricity Grid Code from time time to time and no deviation shall be allowed beyond
to time. No Deviation shall be allowed beyond the such operating range of frequency.
specified operating range of frequency band by the
Note:- The system frequency = f and f = [49.90 Hz < f
Commission from time to time. band
< 50.05 Hz] and this frequency band shall be applied in
this Regulation, wherever applicable;
(D) xxx (D) xxx
(E) Settlement Period: Preparation and settlement of (E) Settlement Period: Preparation and settlement of
‘State Deviation Pool Accounts’ shall be undertaken ‘State Deviation Pool Accounts’ shall be undertaken on
on weekly basis coinciding with mechanism followed weekly basis and the same shall be published in the
for regional deviation settlement accounts. website of the SLDC on weekly basis;
(F) xxx (F) xxx
(G) xxx (G) xxx
(H) xxx (H) xxx
(I) Premise for Allocation of Losses: For the purpose (I) Premise for Allocation of Losses: For scheduling
of State Deviation Pool accounting, the information purpose, the transmission and distribution losses as
regarding average intra-state transmission losses specified in the Commission’s tariff order issued from
for the previous fifty two weeks shall be posted in time to time shall be made applicable amongst the State
the website of the State Load Despatch Centre and Entities to the scheduled drawal by each State Entity in
the average intra-state transmission losses shall be the respective time block.
allocated amongst the State Entities in proportion to
the scheduled drawal by each State Entity;
Provided the distribution losses allocated amongst Provided that the SLDC shall maintain accounts of actual
the State entities shall be as approved by the intra-state transmission system losses of each time block
Commission. and publish on its website;
5 9. Treatment for gaming 9. Treatment for gaming
(1) xxx (1) xxx
(2) If in the proceeding initiated by the Commission (2) If in the proceeding initiated by the Commission or in
or in the enquiry made in this regard under the enquiry made in this regard under sub regulation (1),
sub regulation (1), it is proved that any seller or any it is proved that any seller or any Buyer has indulged in
Buyer has indulged in gaming, the Commission may gaming, the Commission may without prejudice to any
without prejudice to any other action under the Act or other action under the Act or Regulation made there
Regulation made thereunder, disallow any charges under, levy penal charges for deviation to such seller or
for deviation to such seller or Buyer during the period buyer during the period of such gaming.
of such gaming.
(3) Notwithstanding to the sub-regulations (1) and (2),
the generating company may be required to demonstrate
the declared capability of its generating station as and
when asked by the SLDC. In the event of generator
failing to demonstrate the declared capability, the SLDC
may initiate proceedings against such generator by filing
appropriate petition before the Commission as specified
in the sub-regulation (1).Jan. 22, 2025] TAMIL NADU GOVERNMENT GAZETTE 11
6 10. Charges for deviations 10. Charges for deviations
(A) Deviation Charges for Sellers and Buyers: (A) Deviation Charges for Sellers and Buyers:
(1) The charges for the Deviations for all the (1) The charges for the Deviations for all the time-blocks
time-blocks shall be payable for over-drawal by the shall be payable for over-drawal by the Buyer and
Buyer and under-injection by the Seller and receivable under-injection by the Seller and receivable for under-
for under-drawal by the Buyer and over-injection drawal by the Buyer and over-injection by the Seller, which
by the Seller, which are State Entities, and shall are State Entities, and shall be worked out on the average
be worked out on the average frequency of a time- frequency of a time-block by considering the Price Vector
block by considering the Price Vector for Deviation for Deviation Charges as specified in the Annexure-1 of
Charges as specified in the Central Electricity these Regulations and subject to conditions stipulated
Regulatory Commission (Deviation Settlement under clause (2) to (7) of this regulation:
Mechanism and related matters)Regulations, 2014
and its amendments from time to time considering
the methodology specified in the Annexure-1 of these
Regulations and subject to conditions stipulated
under clause (2) to (7) of this regulation:
Provided that a change in sign of the deviation Provided the seller/buyer shall stick on to their schedule
shall be made once every 6 time blocks, failing at each time block and any deviation shall not exist for
which additional charges @ 20% of the deviation more than 6 continuous blocks i.e. a change in sign of
charges applicable shall be levied for the duration of the deviation shall be made once every 6 time blocks,
continuance of violation. failing which additional charges @ 20% over and above
Provided further that the applicability of above the deviation charges applicable shall be levied for the
prescribed additional charges for such failure by duration of continuance of violation i.e. from 7th block
Seller(s) /Buyer(s) shall be applicable from the date Provided further that the applicability of above prescribed
to be notified separately by the Commission. additional charges for such failure by seller(s) / buyer(s)
(2) The Charges for Deviation of generating stations shall be applicable from the date of notification of this
whose tariff is determined by the Commission, amendment;
when actual injection is higher than the scheduled Omitted
generation, shall not exceed the Cap Rate [311]
Paise/kWh to be determined by the Commission from
time to time.
(3) The Charges for the Deviation for the generating
stations other than those covered under Sub-Clause Omitted
(2) of Clause (A) of Regulation 10, irrespective of the
fuel source, when actual injection is higher or lower
than the scheduled generation, shall not exceed the
Cap Rate of [303.04] Paise/kWh.
(4) to (8) xxx
(4) to (8) xxx
(9) The infirm power injected into the grid by a
generating unit of a generating station during the (9) The charges for deviation by way of injection of infirm
testing, prior to COD of the unit shall be paid at power prior to COD shall be zero.
Charges for Deviation for infirm power injected into
the grid, consequent to testing, for a period not
exceeding 6 months or the extended time allowed
by the Commission in the Tamil Nadu Electricity
Regulatory Commission (Grid Connectivity and Intra-
State Open Access Regulations), 2014, as amended
from time to time, subject to ceiling of Cap Rates
corresponding to the 1[main fuel] as determined by
the Central Commission used for such injection as
specified below:
Domestic coal/ Lignite/ 1[1.78] / kWh sent out
Hydro
APM gas as fuel [2.82]/ kWh sent out up
to the date of revision
of price of APM gas
by Government of
India and thereafter, at
the rate to be notified
by the Commission
separately
Imported Coal 1[3.03] / kWh sent out12 TAMIL NADU GOVERN MENT GAZETTE [Part VI—Sec. 2
7 11. Limits on Deviation volume and consequences 11. Limits on Deviation volume and consequences of
of crossing limits crossing limits
(A) The over-drawal or under drawal of electricity by (A) The over-drawal or under drawal of electricity by
any Buyer during a time block shall not exceed 12% any Buyer during a time block shall not exceed 12% of
of its scheduled drawal or [X] MW, the limit arrived as its scheduled drawal or [X] MW, the limit arrived as per
per clause (B) of this regulation , whichever is lower, clause (B) of this regulation , whichever is lower, when
when grid frequency is between range of ‘49.85 Hz grid frequency is between range of ‘49.85 Hz and above
and above to below 50.05 Hz.’ to below 50.05 Hz.’
Provided that from a date not earlier than one year Provided that the total deviation from schedule in energy
as may be notified by the Commission, the total terms during a day shall not be in excess of 3% of the
deviation from schedule in energy terms during a day total schedule for the drawee entities and 1% for the
shall not be in excess of 3% of the total schedule for generators and additional charge of 20% over and
the drawee entities and 1% for the generators and above the daily base DSM payable / receivable shall be
additional charge of 20% of the daily base DSM applicable in case of said violation and this additional
payable / receivable shall be applicable in case of charge is in addition to the penalty for gaming as
said violation. prescribed in the sub-regulation 2 of regulation 9;
(B) The Volume Limit of [ X ] MW for distribution (B) xxx
licensee(s) and Buyers shall be determined as under:
i. xxx
i. Minimum of (12% of schedule, (Peak Demand of
Distribution Licensee or Buyer / ∑NCPD) x State
Volume Limit)
Where NCPD (Non-Coincident Peak Demand)
represents the sum of Peak Demand of Distribution
Licensee(s) and Buyer(s) subject to condition
stipulated under following sub-clause (iii).
ii. State Volume Limit shall be linked to Volume ii. xxx
Limit (L) applicable to the State as per CERC DSM
Regulations and its amendments thereof;
iii. Where Peak Demand of the Distribution Licensee iii. xxx
shall be recorded Peak Demand in the previous
Financial Year or Projected Peak Demand in ensuing
Financial Year, whichever is higher;
Provided that no over drawal of electricity by any Provided that no over-drawal of electricity by any Buyer
Buyer shall be permissible when grid frequency is and under-injection of electricity by the seller shall be
“below 49.85 Hz” and no under drawal of electricity by permissible when the grid frequency is “below 49.90”
any Buyer shall be permissible when grid frequency is and no under-drawal of electricity by any Buyer and
“50.05 Hz and above”. over-injection of electricity by the seller shall be
permissible when grid frequency is “50.05 Hz and above.
(C) xxx (C) xxx
(D) In addition to Charges for Deviation as stipulated (D) In addition to Charges for Deviation as stipulated
under Regulation 10 of these Regulations, Additional under Regulation 10 of these Regulations, Additional
Charge for Deviation shall be applicable for over- Charge for Deviation shall be applicable for over-drawal
drawal as well as under-injection of electricity for each as well as under-injection of electricity for each time block
time block in excess of the volume limit specified in in excess of the volume limit specified in Clause (B) andJan. 22, 2025] TAMIL NADU GOVERNMENT GAZETTE 13
Clause (B) and (C) of this regulation when average (C) of this regulation when average grid frequency of the
grid frequency of the time block is “49.85 Hz and time block is “49.90 Hz and above” at the rates specified
above” at the rates specified in the Table I of Annexure in the Table I of Annexure II in accordance with the
II in accordance with the methodology specified in methodology specified in clause (M) of this regulation;
clause (M) of this regulation:
(E) Additional Charge for Deviation for under-injection
(E) Additional charge for deviation for under-injection
of electricity, during a time-block in excess of the
of electricity shall be the same to all type of sellers
volume limit specified in clause (C) of this regulation
irrespective of the fuel type and whether the tariff of such
when grid frequency is “49.85 Hz and above”, by the
generating station is regulated by the Commission or not;
generating stations regulated by the Commission
using coal or lignite or gas supplied under Administered
Price Mechanism (APM) as the fuel shall be at the
rates specified in Table II of Annexure II in accordance
with the methodology specified in clause (O) of this
regulation;
(F) to (K) xxx
(F) to (K) xxx
(L) In addition to Charges for Deviation as stipulated
under regulation 10 of these Regulations, Additional (L) In addition to Charges for Deviation as stipulated
Charge for Deviation shall be applicable for over- under regulation 10 of these Regulations, Additional
drawal or under-injection of electricity when grid Charge for Deviation shall be applicable for over-drawal
frequency is “below 49.85 Hz” in accordance with the or under-injection of electricity when grid frequency is
methodology specified in clause (N) of this Regulation. “below 49.90 Hz” in accordance with the methodology
specified in clause (N) of this Regulation;
Provided that Additional Charge for Deviation for
under-injection of electricity by a Seller, during the Omitted.
time-block when grid frequency is “below 49.85
Hz”, by the generating stations regulated by the
Commission using coal or lignite or gas supplied
under Administered Price Mechanism (APM) as the
fuel in accordance with the methodology specified in
clause (O) of this Regulation shall be equivalent to
100% of the Cap Rate being equivalent to the energy
charges as billed for the previous month of the Main
fuel.
(M)The Additional Charge for Deviation for over- (M) The Additional Charge for Deviation for over-drawals
drawal and under-injection of electricity for each time and under-injection of electricity for each time block in
block in excess of the volume limit specified in clause excess of the volume limit specified in clause (B) and (C)
(B) and (C) of this Regulation when grid frequency of this Regulation when grid frequency is “49.90 Hz and
is “49.85 Hz and above” shall be as specified by the above” shall be levied as per the Table–I of Annexure –II
Commission as a percentage of the charges for the of this Regulation. This additional charge shall be levied
Deviation corresponding to average grid frequency of over and above the deviation charges as specified in the
the time block with due consideration to the behaviour Annexure – I & III of this Regulation;
of the Buyers and Sellers towards grid discipline:
Provided that the Commission may specify different
rates for additional Charges for Deviation for over
drawals and under injections depending upon
different % of deviation from the schedule in excess
of the volume limit specified in clause (B) and (C) of
this Regulation.14 TAMIL NADU GOVERN MENT GAZETTE [Part VI—Sec. 2
(N) The additional Charge for Deviation for over- (N) The additional Charge for Deviation for over-drawals
drawals and under-injection of electricity for each time and under-injection of electricity for each time block when
block when grid frequency is “below 49.85 Hz” shall grid frequency is “below 49.90 Hz” shall be equivalent to
be as specified by the Commission as a percentage 100% of Charge for Deviation corresponding to average
of the charges for the Deviation corresponding to grid frequency of the time-block. This additional charge
average grid frequency of the time block with due shall be levied over and above the deviation charges as
consideration to the behaviour of the Buyers and specified in the Annexure – I & III of this Regulation;
Sellers towards grid discipline:
Provided that the Commission may specify different
rates for Additional Charges for Deviation for over
drawls and under injections and for different ranges
of frequencies “below 49.85 Hz”.
(O) The Additional Charge for Deviation for under- Omitted.
injection of electricity during the time-block in excess
of the volume limit specified in Clause (C) of this
regulation when grid frequency is ‘49.85 Hz and
above’, by the generating stations regulated by
the Commission using coal/ lignite or gas supplied
under Administered Price Mechanism (APM) as the
fuel shall be as specified by the Commission as
a percentage of the Cap Rate or the Charges for
Deviation corresponding to the grid frequency of
the time block, or both with due consideration to the
behaviour of the generating stations regulated by the
Commission towards grid discipline:
(P) xxx (P) xxx
(Q) The additional Charge for violation of sign change (Q) The additional charges @ 20% of the deviation
stipulation shall be leviable for each such violation charges applicable on daily base DSM payable/
during a day from the date to be notified separately receivable as the case may be shall be levied for the
by the Commission. duration of continuance of violation of sign change
stipulation for each such violation during a day from the
date of notification of this amendment.
To illustrate, the change of sign should take place at To illustrate, the change of sign should take place at least
least once after every six time blocks. Accordingly, the once after every six time blocks. Accordingly, the entity,
entity, starting from time block t1, should change the starting from time block t1, should change the sign after
sign after time block t6. In case, sign change does time block t6. In case, sign change does not take place
not take place immediately after time block t6, but immediately in block t7, but takes place from time block
takes place from time block t7 upto time block t12, t8 upto time block t12, additional charge shall be levied
additional charge shall be levied equivalent to one equivalent to one violation. In case, sign change does not
violation. In case, sign change does not take place take place immediately after time block t12 i.e. in block
immediately after time block t12, but takes place from t13, but takes place from time block t14 upto time block
time block t13 upto time block t18, additional charge t18, additional charge shall be levied equivalent to two
shall be levied equivalent to two violations. violations;Jan. 22, 2025] TAMIL NADU GOVERNMENT GAZETTE 15
7 Provided that in case of run of river projects without
pondage, payment of additional charge for failure to
adhere to sign change requirement shall apply from
such date as may be notified by the Commission.
Such generators shall, however, be required to follow
the sign change requirement and report to SLDC the
reasons for non-adherence to the requirement.
.(R) xxx (R) xxx
(S) xxx (S) xxx
(T) The State Load Despatch Centre shall, on weekly (T) The State Load Despatch Centre shall, on weekly
basis, prepare and publish on its website the records basis, prepare and publish on its website the records
of the Deviation Accounts, specifying the quantum of the Deviation Accounts, specifying the quantum of
of over-drawal/ under-injection and corresponding over-drawal/ under-injection and corresponding amount
amount of Charges for Deviation payable/receivable of Charges for Deviation payable/receivable for each
for each Buyer and Seller for all the time-blocks when Buyer and Seller.
grid frequency was “49.85 Hz and above” and “below
49.85 Hz” separately.
8 13. Accounting of Charges for Deviation 13. Accounting of Charges for Deviation
(1) xxx (1) xxx
(2) xxx (2) xxx
i. xxx i. xxx
ii. xxx ii. xxx
iii. The State entities shall comply with statutory iii. The State entities shall comply with statutory
requirements for payment of applicable statutory requirements for payment of applicable statutory levies,
levies, including but not limited to Goods and Service if any;
Tax (GST), Tax deduction at source (TDS);
iv. xxx
iv. xxx
9 14.Schedule of Payment of Charges for Deviation 14.Schedule of Payment of Charges for Deviation
(1) xxx (1) xxx
(2) If payments against the Charges for Deviation (2) If payments against the Charges for Deviation
including Additional Charges for Deviation are including Additional Charges for Deviation are delayed
delayed by more than two days, i.e., beyond twelve by more than two days, i.e., beyond twelve (12) days
(12) days from the date of issue of the statement by from the date of issue of the statement by the SLDC, the
the SLDC, the defaulting constituent shall have to defaulting constituent shall have to pay simple interest @
pay simple interest @ 0.06% for each day of delay. 0.06% for each day of delay and the same may be added
This is without prejudice to any action that may be in the energy bill, if such facility is available, of such
taken under Section 142 of the Act in addition to any defaulting constituent by the Distribution Licensee on
action under Section 56 of the Act and other relevant receipt of information of such default from the SLDC. This
Regulations. is without prejudice to any action that may be taken under
Section 142 of the Act in addition to any action under
Section 56 of the Act and other relevant Regulations.
(3) xxx (3) xxx
(4) xxx (4) xxx
(5) xxx (5) xxx16 TAMIL NADU GOVERN MENT GAZETTE [Part VI—Sec. 2
10 Annexure-1 Annexure-1
Deviation charges for sellers, buyers, and other Deviation charges for sellers, buyers, and other
conditions: conditions:
1) As specified in the Regulation 10 (A) of these 1) As specified in the Regulation 10(A) of these
Regulations, the charges for the Deviations for all the Regulations, the charges for the Deviations for all the
time-blocks shall be payable for over-drawal by the time-blocks shall be payable for over-drawal by the
Buyer and under-injection by the Seller and receivable Buyer and under-injection by the Seller and receivable
for under-drawal by the Buyer and over-injection by the for under-drawal by the Buyer and over-injection by the
Seller, which are State Entities, and shall be worked out Seller, which are State Entities, and shall be worked out
on the average frequency of a time-block by considering on the average frequency of a time-block by considering
the Price Vector for Deviation Charges as specified in the Price Vector for Deviation Charges as specified in the
the Central Electricity Regulatory Commission (Deviation following table:
Settlement Mechanism and related matters) Regulations,
2014 and its amendments as stipulated in the following
table:
Average Average frequency of Charges for deviation
frequency of time block (Hz)
Charges for Deviation
time block
Below Not below (paise/kwh)
(Hz)
50.05 0.0
Below Not below (Paise/kWh)
50.05 50.04
50.05 0.0 Slope determined by joining the price
Slope determined by joining 50.04 50.03 at not below 50.05 Hz and identified
50.05 50.04 the price at Not Below 50.05 50.03 50.02 price at 50.00 Hz and as detailed in
the note below of this Regulation.
Hz and identified price at 50.02 50.01
50.04 50.03 50.00Hz, and as detailed in the
50.01 50.00 Where P is the Weighted average
note below this Regulation
Area Clearing Price in paisa per kWh
50.03 50.02 discovered in the Day Ahead Market
segments of all the power exchanges
50.02 50.01
50.00 49.99 Slope determined by joining the price
Daily(simple) average Area identified at 50.00 Hz and price at
49.99 49.98
Clearing Price discovered below 49.90 Hz and as detailed in the
50.01 50.00
in The Day Ahead Market 49.98 49.97 note below of this Regulation.
segment of power exchange
49.97 49.96
49.96 49.95
50.00 49.99
49.95 49.94
49.99 49.98 49.94 49.93
49.98 49.97 49.93 49.92
49.97 49.96 49.92 49.91
49.96 49.95 49.91 49.90
49.95 49.94 49.90 1000.00
49.94 49.93 Slope determined by joining
Note:-
the price identified at 50.00Hz
and price at below49.85Hz, i to v xxx
and as detailed in the note
vi. Omitted.
49.93 49.92 Below this Regulation
49.92 49.91 vii to x. xxx
49.91 49.90
49.90 49.89
49.89 49.88
49.88 49.87
49.87 49.86
49.85 800Jan. 22, 2025] TAMIL NADU GOVERNMENT GAZETTE 17
Note:- Note:-
i to v. xxx i to v xxx
vi. The Cap rate for the charges for deviation for the generating vi. Omitted.
stations whose tariff is determined by the Commission shall be
equal to its energy charges as billed for the previous month.
Provided that no retrospective revision of DSM account shall
be allowed even if the energy charges are revised at a later
date
vii to x. xxx vii to x. xxx
11 Annexure-II: Additional Deviation Charges Annexure-II: Additional Deviation Charges
TABLE – I: Additional Deviation Charge (for Seller/Buyer) TABLE – I: Additional Deviation Charge (for
Seller/Buyer)
(A) xxx
(A) xxx
(B) xxx
(B) xxx
TABLE – II: Additional Deviation Charge for Under-Injection Omitted
by Generating Stations Regulated by the Commission Using
Coal or Lignite or Gas Supplied Under Administered Price
Mechanism (APM)
(A) xxx
(B) xxx
12 Annexure – III Annexure – III
Illustration to the DSM Price Vector specified in the Central Illustration to the DSM price vector:
Electricity Regulatory Commission (Deviation Settlement
Mechanism and related matters) Regulations, 2014 and its
amendments under Clause 3.118 TAMIL NADU GOVERN MENT GAZETTE [Part VI—Sec. 2
12
Average frequency of Average frequency of the
the time block (Hz) Charges for deviation time block (Hz) Charges for deviation
(Paise/kWh) (Paise/kWh)
Below Not below Below Not below
50.05 0.00 50.05 0.00
50.05 50.04 1 x P/5 50.05 50.04 1 x P/5
50.04 50.03 2 x P/5 50.04 50.03 2 x P/5
50.03 50.02 3 x P/5 50.03 50.02 3 x P/5
50.02 50.01 4 x P/5 50.02 50.01 4 x P/5
50.01 50.00 P 50.01 50.00 P
50.00 49.99 50.00+15xP/16 50.00 49.99 90.909 + 10 X P/11
49.99 49.98 100.00+14xP/16 49.99 49.98 181.818 + 9 X P/11
49.98 49.97 150.00+13xP/16 49.98 49.97 272.727 + 8 X P/11
49.97 49.96 200.00+12xP/16 49.97 49.96 363.636 + 7 X P/11
49.96 49.95 250.00+11xP/16 49.96 49.95 454.545 + 6 X P/11
49.95 49.94 300.00+10xP/16 49.95 49.94 545.454 + 5 X P/11
49.94 49.93 350.00+9xP/16 49.94 49.93 636.363 + 4 X P/11
49.93 49.92 400.00+8xP/16 49.93 49.92 727.272 + 3 X P/11
49.92 49.91 450.00+7xP/16 49.92 49.91 818.181 + 2 X P/11
49.91 49.90 500.00+6xP/16 49.91 49.90 909.090 + 1 X P/11
49.90 49.89 550.00+5xP/16 49.90 1000.00
49.89 49.88 600.00+4xP/16
Where P is the Weighted average Area Clearing Price
49.88 49.87 650.00+3xP/16 in paisa per kWh discovered in the Day Ahead Market
49.87 49.86 700.00+2xP/16 segments of all the power exchanges.
49.86 49.85 750.00+1xP/16
49.85 800.00
Where P is the Daily average Area Clearing Price in
paisa per kWh discovered in the Day Ahead Market
segment of power exchange.
(By Order of the Tamil Nadu Electricity Regulatory Commission)
Chennai-600 032, C. VEERAMANI,
30th December 2024. Secretary,
Tamil Nadu Electricity Regulatory Commission.
PRINTED AND PUBLISHED BY THE COMMISSIONER OF STATIONERY AND PRINTING, CHENNAI
ON BEHALF OF THE GOVERNMENT OF TAMIL NADU