Sharing of Inter-State Transmission Charges Regulations, 2010

EXTRAORDINARY
III- 4
PART III-Section 4

PUBLISHED BY AUTHORITY

No. 162 NEW DELHI, WEDNESDAY, JUNE 16, 2010

CENTRAL ELECTRICITY REGULATORY COMMISSION

NEW DELHI

No. L-1/44/2010-CERC Dated: 15th June, 2010

NOTIFICATION

In exercise of the powers conferred under Section 178 read with Part V of the Electricity Act,

2003 (36 of 2003), and all other powers enabling it in this behalf, and after previous

publication, the Central Electricity Regulatory Commission hereby makes the following

regulations:

CHAPTER 1: PRELIMINARY

1. Short title, extent and commencement.

(1) These regulations may be called the Central Electricity Regulatory Commission

(Sharing of Inter-State Transmission Charges and Losses) Regulations, 2010.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

(2) These regulations shall apply to all Designated ISTS Customers, Inter State

Transmission Licensees, NLDC, RLDC, SLDCs, and RPCs.

(3) These regulations shall come into force from [1.7.2011]1, and unless reviewed earlier

or extended by the Commission, shall remain in force for a period of 5 years from the

date of commencement specified above.

2. Definitions.

(1) In these Regulations, unless the context otherwise requires:-

a) Act means the Electricity Act, 2003 (36 of 2003);

[(b) „Application Period‟ means the period of application of the charges

determined as per these regulations and shall be of 3 (three) months duration

i.e. April to June, July to September, October to December, and January to

March in a financial year:

Provided that in exceptional circumstances, the Commission may extend or

curtail the duration of the application period for the reasons to be recorded in

writing.]2;

[(c) „Approved Injection‟ means the injection in MW computed by the

Implementing Agency for each Application Period on the basis of maximum

injection made during the corresponding Application Periods of last three (3)

years and validated by the Validation Committee for the DICs at the ex-bus of

the generators or any other injection point of the DICs into the ISTS, and

1
Came into force w.e.f 1.7.2011 vide notification number L-1/44/2010-CERC dated 01.04.2011 in Gazette No.
70
2
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

taking into account the generation data submitted by the DICs incorporating

total injection into the grid:

Provided that the overload capability of a generating unit shall not be used for

calculating the approved injection:

Provided further that where long term access (LTA) has been granted by the

CTU, the LTA quantum, and where long term access has not been granted by

the CTU, the installed capacity of the generating unit excluding the auxiliary

power consumption, shall be considered for the purpose of computation of

approved injection.]3

d) Approved Additional Medium Term Injection means the additional injection,

as per the Medium Term Open Access approved by CTU after submission of

data to NLDC by the Designated ISTS Customer over and above the

Approved Injection for the Designated ISTS Customer for each representative

block of months, [ ]4 at the ex-bus of the generator or any other injection

point of the Designated ISTS Customer into the ISTS;

e) Approved Short Term Injection means the injection, as per the Short Term

Open Access approved by RLDC / NLDC such injection including all

injections cleared on the power exchange;

[(f) „Approved Withdrawal‟ means the withdrawal in MW computed by the

Implementing Agency for each application period on the basis of the actual

peak met during the corresponding application periods of last three (3) years

and validated by the Validation Committee for any DIC in a control area after

3
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
4
Deleted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

taking into account the aggregated withdrawal from all nodes to which DIC is

connected and which affect the flow in the ISTS, and the anticipated maximum

demand to be met as submitted by the DIC:

Provided that the overload capability of a generating unit in which the DIC has

an allocation or with which the DIC has signed an agreement, shall not be used

for calculating the approved withdrawal under long term access (LTA).]5

[(g) Approved Additional Medium Term Withdrawal means the additional

withdrawal by a DIC as per the Medium Term Open Access approved by CTU

after submission of data to the Implementing Agency by the concerned DIC.]6;

h) Approved Short Term Withdrawl means withdrawl as per the Short Term

Open Access approved by RLDC/NLDC and where such withdrawl includes

all withdrawals cleared on the power exchange;

i) Basic Network shall mean the power system of the country at voltage levels

132 kV and above and 110 kV where generators are connected, HVDC

transmission network and all Generator and loads connected to it;

j) Bulk Power Transmission Agreement (BPTA) means the agreements

between the ISTS licensees and the Designated ISTS Customers of the ISTS

under the pre-existing arrangements for ISTS development and operations;

k) Deemed Inter State Transmission System (Deemed ISTS) means such

transmission system which has regulatory approval of the Commission as

being used for interstate transmission of power and qualified as ISTS for the

purpose of these Regulations unless otherwise specified;

5
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
6
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

[(l) Designated ISTS Customer or DIC means the user of any segment(s) or

element(s) of the ISTS and shall include generator, State Transmission Utility,

State Electricity Board or load serving entity including Bulk Consumer and

any other entity or person directly connected to the ISTS and shall further

include any intra-State entity who has obtained Medium Term Open Access or

Long Term Access to ISTS.]7

[Provided that where the ISTS charges were being billed to the distribution

companies or any designated agency in the State for purchasing power before

implementation of these regulations, the distribution companies or the

designated agency, as the case may be, shall be treated as Designated ISTS

Customer in that State for the purpose of preparation of Regional Transmission

Account (RTA) by Regional Power Committees and for the purpose of billing

and collection by the CTU:

Provided further that after implementation of these regulations, the States may

designate any agency as Designated ISTS Customer for the above purpose.]8

[(l-i) „HVDC Charge‟ means the transmission charges shared for use of HVDC

transmission systems as provided under Regulation 11 of these regulations.]9

m) Hybrid Methodology shall mean the hybrid of the Marginal Participation

Method and the Average Participation method detailed in Chapter-3 of these

regulations and in Annexure - I hereto.

7
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
8
Added vide First Amendment Regulations, 2011, w.e.f. 25.11.2011
9
Inserted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

n) ['Implementing Agency (IA)' means the agency designated by the

Commission to undertake the computation of allocation of transmission

charges and transmission losses at various nodes/zones for the Application

Period along with other functions mandated under these regulations or as may

be assigned by the Commission from time to time.]10

o) Loss Allocation Factor of a bus measures the losses attributed to that node

and shall be computed as explained in the Annexure - I of these regulations.

[(o-ii) „Merchant Power Plant‟ means a generating station or unit thereof whose

tariff either for the whole capacity or for the part capacity is not determined

under Section 62 or Section 63 of the Act and which sells electricity in the

open market corresponding to such capacity and the term„merchant capacity‟

shall be construed accordingly.]11

p) Monthly Transmission Charge means the transmission charges (inclusive of

incentives) payable for each calendar month as given in the Terms and

Conditions of Tariff Regulations in force;

q) Node shall mean a sub-station or a switchyard of a generator;

r) Point of Connection (PoC) Charging Method shall mean the methodology

of computation of sharing of ISTS charges and losses amongst Designated

ISTS Customers, which depends on the location of the node in the grid and is

calculated in accordance with Regulation 7(1(q)) and 7(1(s)) of chapter 4 of

these regulations;

10
Substituted vide Second Amendment Regulations, 2012. w.e.f. 29.03.2012
11
Inserted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

s) Point of Connection (PoC) transmission charges are the nodal / zonal

charges determined using the Point of Connection charging method.

t) Participation Factor of a node in any transmission line means the percentage

usage of that line by a node, whether a generator node or a demand node as

explained in Annexure - I of these regulations.

[(t-i) „Reliability Support Charge‟ means the Charge for reliability benefits

which accrue to the DICs by virtue of operating in an integrated grid.

(t-ii) „Reliability Support Charges Sharing Methodology‟ means the mechanism

for determination and sharing of Reliability Support Charges as specified in

sub-clause (q) of clause (1) of Regulation 7 of these Regulations and para

2.8.1.b. of Annexure-I.]12

[[(t-iii)]13 Target Region means the region to which a generator proposes to sell

power after obtaining Long-term Access from the CTU and for which

beneficiaries in the said region have not been identified.]14

(u) Transmission Service Agreement (TSA) shall mean the agreement to be

entered into between the Designated ISTS Customer(s) and ISTS Licensee(s)

in terms of Chapter 6;

[(u-i) „Validation Committee‟ means the committee appointed by the Commission

comprising officers from the Commission, the Implementing Agency, each of

the RPCs, CTU, CEA, STUs for the purpose of discharging various functions

12
Inserted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
13
Renumbered vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
14
Inserted vide First Amendment Regulations, 2011, w.e.f. 25.11.2011

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 Sharing of Inter-State Transmission Charges Regulations, 2010

vested under these regulations, and the meetings of the committee shall be

chaired by a nominee of the Commission.]15

[ ]16

(y) [‘Yearly Transmission Charge (YTC)’ means the Annual Transmission

Charges for the existing and new transmission assets of the inter-State

transmission licensees, deemed ISTS Licensees, owners of inter-State

transmission lines connecting two States and owners of non-ISTS lines

certified by Regional Power Committees for inter-State transmission of power,

determined by the Appropriate Commission under Section 62 of the Act or

adopted by the Appropriate Commission under Section 63 of the Act or as

otherwise provided in these Regulations.]17

[Provided that in case of non-ISTS lines, the asset-wise tariff determined by

the respective State Commissions or approved by the Central Commission

based on the approved Annual Revenue Requirement of STU, shall be used:

Provided further that transmission charges received by the STU under these

regulations shall be adjusted in the Annual Revenue Requirement of the

concerned STU approved by the respective State Commission.]18

(2) Words and expressions used in these Regulations and not defined herein but defined

in the Act or regulations made by the Commission, shall have the meanings assigned

15
Inserted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
16
Sub-clauses (v), (w) and (x) of clause (1) of Regulation 2 Deleted vide Third Amendment Regulations, 2015
w.e.f. 01.05.2015.
17
Initially substituted vide First Amendment Regulations, 2011, w.e.f. 25.11.2011 and later substituted by the
Second Amendment Regulations, 2012 dated 29.03.2012
18
Inserted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015
.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

to them respectively in the Act, and regulations made by the Commission from time

to time.

CHAPTER 2: SCOPE OF THE REGULATIONS

3. Yearly Transmission Charges, revenue requirement on account of foreign exchange

rate variation, changes in interest rates etc. as approved by the Commission and

Losses shall be shared amongst the following categories of Designated ISTS

Customers who use the ISTS:-

[(a) Generating Stations (i) which are regional entities as defined in the Indian

Electricity Grid Code (IEGC) or (ii) are having LTA or MTOA to ISTS and

are connected either to STU or ISTS or both.]19

[(b) State Electricity Boards/State Transmission Utilities connected with ISTS or

designated agency in the State (on behalf of distribution companies, generators

and other bulk customers connected to the transmission system owned by the

SEB/STU/ intra-State transmission licensee);]20

(c) Any bulk consumer directly connected with the ISTS, and

(d) Any designated entity representing a physically connected entity as per clauses

(a), (b) and (c) above.

19
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
20
Substituted vide First Amendment Regulations, 2011, w.e.f. 25.11.2011

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 Sharing of Inter-State Transmission Charges Regulations, 2010

CHAPTER 3: PRINCIPLES AND MECHANISM FOR SHARING OF ISTS

CHARGES AND LOSSES

4. Principles for sharing ISTS charges and losses.

(1) Based on the Yearly Transmission Charges of ISTS Transmission Licensees and

transmission losses in the ISTS network, the Implementing Agency shall compute the

Point of Connection charges and Loss Allocation Factors for all DICs:-

(a) Using load-flow based methods; and

(b) based on the Point of Connection Charging method.

(2) A detailed explanation of the Hybrid methodology to be applied for sharing the ISTS

charges and losses amongst the Designated ISTS Customers is set out in Annexure - I

to these regulations, which may be reviewed by the Commission from time to time

either upon an application by any interested party or otherwise .

5. Mechanism to share ISTS transmission charges.

(1) The sharing of ISTS transmission charges between Designated ISTS Customers shall

be computed for an Application Period and shall be determined in advance and shall

be subject to periodic true-up as specified subsequently in these regulations;

(2) The sharing of ISTS transmission charges shall be based on the technical and

commercial information provided by various Designated ISTS Customers, ISTS

Transmission Licensees, and any other relevant entity, including the NLDC, RLDCs

and SLDCs to the Implementing Agency.

Provided that in the event of such information not being available within the

stipulated timeframe or to the level of detail required, the Commission may authorise

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 Sharing of Inter-State Transmission Charges Regulations, 2010

the Implementing Agency to obtain such information from alternative sources as per

the procedure as may be approved by the Commission in this behalf.

(3) The mechanism for sharing of ISTS charges shall ensure that:-

(a) The Yearly Transmission Charge of the ISTS Licensees are fully and exactly

recovered; and

(b) Any adjustment towards Yearly Transmission Charge on account of change

in commissioning schedule of elements of the power system and change in

factors constituting the transmission charge, approved by the Commission,

e.g., FERV, Changes in interest rates shall be fully and exactly recovered etc.,

as specified subsequently in these regulations.

(4) The Point of Connection transmission charges shall be computed in terms of Rupees

per Mega Watt per month. The amount to be recovered from any Designated ISTS

Customer towards ISTS charges shall be computed on a monthly basis as per these

regulations. The Point of Connection transmission charges for short term open

access transactions shall be in terms of [Paisa/unit]21 and shall be applicable for the

duration of short term open access approved by the RLDC/NLDC.

(5) The Implementing Agency may, after seeking approval of the Commission, conduct

studies from time to time to refine the mechanism for sharing of transmission charges

and losses as detailed in Annexure – I to these Regulations.

21
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

6. Mechanism of sharing of ISTS losses.

(1) The schedule of electricity of Designated ISTS Customers shall be adjusted to account

for energy losses in the transmission system as estimated by the Regional Load

Despatch Centre and the State Load Despatch Centre concerned. These shall be

applied in accordance with the detailed procedure to be prepared by NLDC within 30

days of the notification of these regulations. The losses shall be apportioned based on

the loss allocation factors determined using the Hybrid methodology.

(2) The sharing of ISTS losses shall be computed based on the information provided by

various Designated ISTS Customers, ISTS Licensees, and any other relevant entity,

including the NLDC, RLDCs and SLDCs and submitted to the Implementing

Agency.

Provided that in the event of such information not being available within the

stipulated timeframe or to the level of detail required, the Commission may authorise

the Implementing Agency to obtain such information from alternate sources as may

be approved for use by the Commission.

(3) The applicable transmission losses for the ISTS shall be declared in advance and shall

not be revised retrospectively.

(4) The Implementing Agency may, after seeking approval of the Commission, conduct

studies from time to time to refine the ISTS loss allocation methods.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

CHAPTER 4: PROCESSES FOR SHARING OF TRANSMISSION CHARGES AND

LOSSES

7. Process to determine Point of Connection Transmission Charges and Losses

allocations.

(1) The process to determine the allocation of transmission charges and losses shall be as

under, and as per timelines set out subsequently in Chapter 7 of these regulations:

(a) The Implementing Agency shall collect the Basic Network data pertaining to

the network elements and the generation and load at the various network nodes

from all concerned entities including Designated ISTS Customers,

transmission licensees, NLDC, RLDCs, SLDCs, RPCs;

(b) The Basic Network shall not contain any electricity system, electrical plant or

line below 132 kV except where generators are connected to the grid at 110

kV. Power flow into a lower voltage system from the voltage levels indicated

in the definition of the Basic Network shall be considered as load at that sub-

station. Power flow from a lower voltage system into the electricity systems at

the voltage levels shall be considered as generation at that sub-station;

(c) The dedicated transmission lines constructed, owned and operated by the ISTS

Licensees shall be considered to be a part of the Basic Network. Dedicated

lines constructed, owned and operated by the generator shall not be considered

as a part of the Basic Network. In the latter case, the generator will be deemed

to be connected directly to the ISTS;

[(d) Nodal generation information shall be based on the forecast data provided by

the DICs. Such forecast data shall incorporate estimate of total maximum

injection into the grid, considering the injection under long term access,

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 Sharing of Inter-State Transmission Charges Regulations, 2010

medium term open access and short term open access during an Application

Period. The forecast data submitted by the DICs shall be vetted by the

Implementing Agency based on historical maximum generation levels

obtained from the NLDC/RLDCs/SLDCs. Any variation in the forecast

generation shall be communicated to the concerned DIC by the Implementing

Agency.

The forecast generation in respect of each DIC shall be normalized with

respect to forecast All India Peak Demand met to create base case for load

generation balance to arrive at the approved injection.

Approved injection figures so arrived shall be validated by the Validation

Committee based on the injection data submitted by the DICs. In case data

submitted by any DIC is different from the data computed on the basis of last

three years‟ actual data, requisite justification by the concerned DIC shall be

submitted for considering its data.

The generating station for which three years‟ data are not available, forecast

shall be prepared based on available data and the data submitted by the

concerned generating station. In case no data is submitted by the generating

station, estimated injection as prepared by the Implementing Agency shall be

considered as approved injection.

In case of DICs which are injecting into the grid for the first time, approved

injection based on norms formulated by the Validation Committee for

generation based on different types of stations shall be considered.

All withdrawal DICs shall also submit estimated maximum generation from

their own generating stations during the Application Period to the

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 Sharing of Inter-State Transmission Charges Regulations, 2010

Implementing Agency to prepare the Base Case for load generation balance.

The data as validated by the Validation Committee shall be final.

Mis-declaration by a DIC beyond +/- 20% for two consecutive quarters shall

be treated as gaming. Unless reasonably explained by the concerned DIC, the

Implementing Agency shall report the matter to the Commission for

appropriate directions.]22

[(e) Forecast demand data shall be submitted by the DICs for each node or a group

of nodes in a zone, identified by the Implementing Agency under these

regulations. The forecast demand data shall incorporate estimate of maximum

withdrawal. The forecast demand data submitted by DICs shall be vetted by

the Implementing Agency based on historical demand met of each DIC during

the periods corresponding to the Application Period. Any variation in the

forecast demand shall be communicated by the Implementing Agency to the

concerned DIC.

In case data submitted by a DIC is different from the data forecast on the basis

of last three years actual data, requisite justification shall be submitted by the

concerned DIC for considering its data. The data as validated by the

Validation Committee shall be final.

Mis-declaration by a DIC beyond +/- 20% for two consecutive quarters shall

be treated as gaming. Unless reasonably explained by the concerned DIC, the

Implementing Agency shall report the matter to the Commission for

appropriate directions.]23

22
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
23
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

(f) Implementing Agency shall prepare detailed procedures and formats for

collection of the generation and demand data from each Designated ISTS

Customer and the data pertaining to the Basic Network within 30 days of the

notification of these regulations;

[(g) In the event of difference of opinion between any DIC and the Implementing

Agency with regard to the revised generation and demand data so obtained,

the Validation Committee shall take final decision after considering the point

of view of the concerned DIC and the Implementing Agency.]24

(h) The Implementing Agency shall run AC load flows using the Basic Network,

nodal generation and nodal demand. To ensure Load Generation balance,

adjustment may be required to be made on the vetted generation and demand

data.

[(i) Basic Network along with the converged load flow results for the injection and

withdrawal data as per sub-clauses (d) and (e) of clause (1) of this Regulation

shall be validated by the Validation Committee. The Basic Network, nodal

generation, nodal demand and the load flow results for each Application

Period shall be validated by the Validation Committee not later than 15 days

prior to the commencement of each Application Period. The approved Basic

Network, nodal generation, nodal demand along with the load flow results

shall be made available on the websites of the Commission and the

Implementing Agency immediately after its approval by the Validation

Committee.

24
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

Provided that non-submission of data in time for computation of transmission

charges shall be treated as non-compliance of the regulations and action as

considered appropriate shall be taken by the Commission after giving an

opportunity of hearing to the defaulting DIC.]25

(j) Approved Basic Network, nodal generation and nodal demand data shall form

the base for computation of Marginal Participation factors and loss allocation

factors.

[(k) Consequent to development of load flows on the Basic Network, the Hybrid

Methodology shall be applied by the Implementing Agency on the Basic

Network to determine the transmission charges and loss allocation factors

attributable to each node in the power system.]26

[(l) Overall charges to be shared among the nodes shall be computed based on the

Yearly Transmission Charges apportioned to each of the lines of the ISTS

Licensees. The Yearly Transmission Charges, computed for the assets for each

voltage level and conductor configuration shall be provided by the respective

ISTS transmission licensees. The ISTS Licensees, deemed ISTS Licensees and

owners of the non-ISTS Lines certified by the Regional Power Committees

shall give the total Yearly Transmission Charges of their transmission assets,

whose charges are to be recovered through the PoC mechanism in the

application period along with circuit kilometres at each voltage level and for

each conductor configuration. The total Yearly Transmission Charges shall be

apportioned for each voltage level and conductor configuration based on the

25
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
26
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

ratio of the indicative cost levels furnished by CTU at the beginning of each

year or application period and approved by the Commission:

Provided that the YTC shall be revised on a six monthly basis i.e. on 1st April

and 1st October in the first full year and subsequently on quarterly basis, i.e. on

1st April, 1st July, 1st October and 1st December.]27

[Provided further that there shall be nine slab rates for PoC charges. The slab

rates shall be computed by the Implementing Agency based on the

methodology given in Annexure-I to these regulations. The slab rates shall be

approved by the Commission for each Application Period. The number of

slabs shall be reviewed by the Commission after two years.]28

(m) [ ]29

[(n) For the computation of transmission charges at each node as per Hybrid

Methodology, cost of ISTS transmission licensees whose lines feature on the

Basic Network shall be considered:

Provided that in case of STU lines which are physically inter-State lines and

whose tariff is approved by the Commission, such tariff shall be considered

for computation of PoC charges:

Provided further that in case of non-ISTS lines (lines owned by STUs but

being used for carrying inter-State power as certified by respective RPCs), the

asset-wise tariff as approved by the respective State Commission shall be

27
Substituted vide First Amendment Regulations, 2011, w.e.f. 25.11.2011
28
Initially proviso was added vide Second Amendment Regulations, 2012. w.e.f. 29.03.2012 later the last
proviso was substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
29
Deleted vide First Amendment Regulations, 2011, w.e.f. 25.11.2011

847
 Sharing of Inter-State Transmission Charges Regulations, 2010

considered. Where asset-wise tariff is not available, the tariff as computed by

the Commission based on the ARR of the STUs (as approved by respective

State Commissions) by adopting the methodology similar to the methodology

used for ISTS transmission licensees shall be considered. The transmission

charges received by the concerned STU on this account shall be adjusted in its

approved Annual Revenue Requirement.]30

[(o) The participation factors, and the Point of Connection nodal and zonal rates

thus determined, shall be computed for each Application Period. Detailed

methodology for preparing the Base Case shall be in accordance with the

methodology given in Annexure-I to these regulations.

Provided that the load flow studies shall be carried out by the Implementing

Agency for each Application Period.]31

(p) In order to give proper signals towards transmission charges based on distance

and direction, the transmission charge per circuit kilometre shall have to be

made uniform for each voltage level and conductor configuration. For this

purpose, total transmission charges to be recovered for all lines of a given

voltage level and conductor configuration shall be divided by the total circuit

kilometre for that voltage level and line configuration in order to arrive at the

average transmission charge per circuit kilometre for that voltage level and

conductor configuration. [ ]32. The total transmission charge for each line

shall be recovered in proportion to the participation factors as detailed in

30
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
31
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
32
Sentence deleted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

[Annexure]33 to these Regulations. The process shall thereby ensure that the

total charges for the lines are fully recovered;

[(q) The recovery of the Yearly Transmission Charges (YTC) of the ISTS network

shall be based on the Hybrid Methodology (PoC charge), Reliability Support

Charge and HVDC Charge. Ten percent (10%) of the Yearly Transmission

Charges shall be recovered through Reliability Support Charge Sharing

methodology. The Commission may review the weightage accorded to

Reliability Support Charge whenever deemed necessary. The Reliability

support charge rates shall be determined separately and shall not be mixed

with zonal PoC rates. The Reliability Support Charge shall be payable by the

DICs in proportion to their Approved Withdrawal. In case of Injection DIC

shaving Long Term Access to target region, Reliability Support Charges shall

also be payable in proportion to their Approved Injection.]34

(r) The loss allocation factors shall be computed for each season using the Hybrid

method as explained in Annexure - I to these regulations. The loss allocation

factors shall be applied to the total losses, computed as per the procedures

developed by the NLDC under these regulations, to attribute losses to each

Designated ISTS Customer .

[(s) The losses shall be apportioned to the DICs by suitably adjusting their

scheduled MWs. The extent of adjustment shall be on the basis of losses

apportioned to each DIC based on the Hybrid Methodology. The Detailed

33
Substituted vide Second Amendment Regulations, 2012. w.e.f. 29.03.2012
34
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

Procedure for application of losses to various DICs shall be modified by

NLDC with the approval of the Commission.

Provided that there shall be nine slabs for calculation of transmission losses

which shall be expressed in terms of percentage. There shall be 4 steps above

the average loss and 4 steps below the average loss with a slab size of 0.25%

subject to minimum loss of Zero percent. The slabs may be reviewed by the

Commission after two years.]35

(t) [The Implementing Agency shall aggregate Point of Connection charges for

the geographically and electrically contiguous nodes on the ISTS to create

zones within the geographical boundary of the State, in order to arrive at

uniform zonal rate in `/MW/ month. The Implementing Agency shall create

zones for generation and demand. Such zoning shall be governed by the

following considerations:]36

(i) Zones shall contain relevant nodes whose costs (as determined from the

output from the Hybrid method) are within the same range.

(ii) [The nodes within zones shall be combined in a manner such that they are

geographically and electrically proximate. The demand zones shall be the

geographical boundary of the State.]37

(iii) The same zone can act as a generation zone as well as a demand zone for

the purpose of calculation of Generation and demand zonal charges

respectively. Even as it is preferable to have similar zones for generation and

35
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
36
Substituted vide Second Amendment Regulations, 2012. w.e.f. 29.03.2012
37
Substituted vide Second Amendment Regulations, 2012. w.e.f. 29.03. 2012

850
 Sharing of Inter-State Transmission Charges Regulations, 2010

demand, this shall be pursued only when practical, and other conditions for

zoning are met

[(iv) Any inter-State Generating Station connected to the 400 kV inter-State

Transmission System (including those connected to both 400 kV ISTS and

STU) shall be treated as a separate zone and shall not be clubbed with other

generator nodes in the area, for the purpose of calculation of PoC injection

rate:

Provided that in case of a merchant power plant in a State connected to 400

kV inter-State Transmission System, with zero LTA or part LTA, injection

considered in the Base Case or LTA, whichever is higher, shall be considered

to arrive at the PoC injection rate.]38

[(v). ]39

(vi) Typically the zones shall remain fixed in a given financial year unless

significant changes in the power system during a year require re-zoning. Any

such re-zoning shall be approved by the Commission before implementation

by the Implementing Agency.

[(vii) In case an ISGS is connected only to STU network and the shares of the

beneficiaries of the said station are being delivered through the STU network,

such a line of the STU network shall be considered as an ISTS for the purpose

of these regulations.]40

38
Initially Substituted vide Second Amendment Regulations, 2012 and later substituted vide Third Amendment
Regulations, 2015 w.e.f. 01.05.2015.
39
Deleted vide Second Amendment Regulations, 2012. w.e.f. 29.03. 2012
40
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

851
 Sharing of Inter-State Transmission Charges Regulations, 2010

(u) No transmission charges for the use of ISTS network shall be charged to solar

based generation. This shall be applicable for the useful life of the projects

commissioned in next three years.

[Provided that the above provision shall also be applicable for the useful life of

the projects commissioned during the period 1.7.2014 to 30.6.2017.]41

(v) No transmission losses for the use of ISTS network shall be attributed to solar

based generation. This shall be applicable for the useful life of the projects

commissioned in next three years.

[Provided that the above provision shall also be applicable for the useful life of

the projects commissioned during the period 1.7.2014 to 30.6.2017.]42

[(w) No transmission charges for the use of ISTS network shall be Charged to
incremental gas based generation from e-bid RLNG for the years 2015-16 and
2016-17.

(x) No transmission losses for the use of ISTS network shall be attributed to
incremental gas based generation from e-bid RLNG for the year 2015-16 and
2016-17]43

(2) Detailed methodological aspects are set out in Annexure - I to these regulations. The

Commission may modify or update the above processes from time to time based on

the emergent needs for determining the Point of Connection transmission charges and

allocation of losses.

41
Added vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
42
Added vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
43
Added vide Fourth Amendment Regulations, 2015 w.e.f 01.06.2015

852
 Sharing of Inter-State Transmission Charges Regulations, 2010

8. Determination of specific transmission charges applicable for a Designated ISTS

Customer.

(1) Based on the Yearly Transmission Charges determined by the Commission, the

Implementing Agency shall determine the charges applicable to each Designated

ISTS Customer for use of the ISTS to the extent of the Approved Withdrawal or

Approved Injection in the ISTS. Each Designated ISTS Customer shall ensure that the

forecast data of demand and injection for each season is furnished to the

Implementing Agency as per the timelines described in these regulations [ ]44 as

specified in Chapter 7 of these regulations;

(2) In the event of a Designated ISTS Customer failing to provide its requisition for

demand or injection for an Application Period, the last demand or injection forecast

supplied by the Designated ISTS Customer and as adjusted by the Implementing

Agency for Load Flow Analysis shall be deemed to be Approved Withdrawal or

Approved Injection, as the case may be, for the Application Period;

(3) The transmission charges for any month shall be determined as per Regulation 11 of

these Regulations;

(4) In case the metered MWs (ex-bus) of a power station or the aggregate demand of a

Designated ISTS Customer exceeds, in any time block,

(a) In case of generators: The Approved Injection + Approved Additional

Medium Term Injection + Approved Short Term Injection or;

(b) In case of demand customers: The Approved Withdrawal + Approved

Additional Medium Term Withdrawal + Approved Short Term Demand,

44
Deleted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

853
 Sharing of Inter-State Transmission Charges Regulations, 2010

Then for first 20% deviation in any time block, the Designated ISTS Customer shall

be required to pay transmission charges for excess generation or demand at the same

rate and beyond this limit, the Designated ISTS Customer shall be required to pay

additional transmission charges which shall be 25% above the zonal Point of

Connection charges determined for zone where the Designated ISTS Customer is

physically located. Such additional charges shall not be charged to the generators in

case of rescheduling of the planned maintenance program which is beyond the control

of the generator and certified to be so by the appropriate RPC. Further, any payment

on account of additional charges for deviation by the generator shall not be charged to

its long term customer and shall be payable by the generator;

[(5) Where the Approved Withdrawal or Approved Injection in case of a DIC is not

materializing either partly or fully for any reason whatsoever, the concerned DIC shall

be obliged to pay the transmission charges allocated under these regulations:

Provided that in case the commissioning of a generating station or unit thereof is

delayed, the generator shall be liable to pay Withdrawal Charges corresponding to its

Long term Access from the date the Long Term Access granted by CTU becomes

effective. The Withdrawal Charges shall be at the average withdrawal rate of the

target region:

Provided further that where the operationalization of LTA is contingent upon

commissioning of several transmission lines or elements and only some of the

transmission lines or elements have been declared commercial, the generator shall pay

the transmission charges for LTA operationalised corresponding to the transmission

system commissioned:

854
 Sharing of Inter-State Transmission Charges Regulations, 2010

Provided also that where the construction of dedicated transmission line has been

taken up by the CTU or the transmission licensee, the transmission charges for such

dedicated transmission line shall be payable by the generator as provided in the

Regulation 8 (8) of the Connectivity Regulations:

Provided also that during the period when a generating station draws start-up power or

injects infirm power before commencement of LTA, withdrawal or injection charges

corresponding to the actual injection or withdrawal shall be payable by the generating

station and such amount shall be adjusted in the next quarter, from the ISTS

transmission charges to be recovered through PoC mechanism from all DICs:

Provided also that CTU shall maintain a separate account for the above amount

received in a quarter and deduct the same from the transmission charges of ISTS

considered in PoC calculation for the next application period.]45

[(6) For Long Term Transmission Customers availing power supply from inter-State

generating stations, the charges attributable to such generation for long term supply

shall be calculated directly at drawal nodes as per methodology given in the

Annexure-I. Such mechanism shall be effective only after commercial operation of

the generator. Till then it shall be the responsibility of the generator to pay

transmission charges.]46

45
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
46
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

855
 Sharing of Inter-State Transmission Charges Regulations, 2010

9. Differentiation among various categories of transmission Designated ISTS

Customers.

(1) There shall be no differentiation in Point of Connection charges between the long

term, medium term and short term Designated ISTS Customer s of the transmission

system.

CHAPTER 5: ACCOUNTING, BILLING AND COLLECTION OF CHARGES

10. Accounting of charges.

(1) Monthly Transmission Accounts applicable for various Designated ISTS Customers

in each region shall be prepared by the respective RPC on the basis of:

(a) Approved Withdrawal / Injection (MW) [ ]47 to be received from Implementing

Agency,

(b) Zonal Point of Connection charge (Rs / MW / month) to be received from

Implementing Agency

(c) Approved Additional Medium Term Withdrawal / Injection (MW) to be received

from RLDC / NLDC,

(d) Processed meter reading from all SEMs for computation of deviations from the

sum of the Approved Withdrawal / Injection, Approved Additional Medium Term

Withdrawal / Injection and Approved Short Term Withdrawal / Injection (MW) and

time blocks for which such deviation is recorded. This data shall be received from

RLDCs,

47
Deleted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

856
 Sharing of Inter-State Transmission Charges Regulations, 2010

[RPCs shall, based on Regulation 10 (1) (a), 10 (1) (b) and 10 (1) (c), issue Regional

Transmission Accounts on the next working day of the issue of Regional Energy

Account for the previous month, to all the Designated ISTS Customers, CTU and

other ISTS Transmission Licensees and display the same on its web site.

RPCs shall, based on Regulation 10 (1) (d), issue Regional Transmission Deviation

Accounts by 15th of every month for the previous month to all Designated ISTS

Customers, CTU and other ISTS Transmission Licensees and display the same on the

website of the respective RPCs.]48

11. Billing.

(1) The CTU shall be responsible for raising the transmission bills, collection and

disbursement of transmission charges to ISTS transmission licensees. Any expenses

incurred by CTU on account of this function shall be reimbursed as part of YEARLY

TRANSMISSION CHARGE;

(2) The bill for the use of the ISTS shall be raised by the CTU on the concerned

Designated ISTS Customers. The SEB/STU may recover the transmission charges for

the use of the ISTS from the distribution companies, generators and bulk customers

connected to the transmission system owned by the SEB/STU/intrastate transmission

licensee in a manner approved by the Appropriate Commission.

(3) The billing for ISTS charges for all Designated ISTS Customers shall be on the basis

of Rs./MW/Month, and shall be raised by the CTU in three parts.

48
Substituted vide Second Amendment Regulations, 2012.w.e.f. 29.03. 2012

857
 Sharing of Inter-State Transmission Charges Regulations, 2010

[(4) The first part of the bill shall recover charges for use of the transmission assets of the

ISTS Licensees based on the Point of Connection methodology. This part of the bill

shall be computed in three sub-parts as under:

1. Point of Connection transmission charge towards LTA/MTOA

For Generators having LTA to target region:

PoC transmission rate of generation zone in Rs/ MW / month  Approved

Injection

For Demand:

PoC transmission rate for demand zone in Rs/ MW /month  Approved

Withdrawal

2. Reliability Support Charge For Generators having LTA to target region:

Reliability Support Rate in Rs/ MW / month  Approved Injection

For Demand:

Reliability support rate in Rs/ MW / month  Approved Withdrawal

3. HVDC charge

(i) 10% of Monthly Transmission Charges (MTC) of HVDC transmission system

shall form part of Reliability Support Charges and the balance shall be billed as

detailed below:

Transmission charges for HVDC system created to supply power to specific regions

shall be borne by DICs of such regions. The HVDC Charge shall be payable by

DICs of the Region in proportion to their Approved Withdrawal. In case of Injection

858
 Sharing of Inter-State Transmission Charges Regulations, 2010

DICs having Long Term Access to target region, it shall also be payable in

proportion to their Approved Injection.

For Generators having LTA to target region:

HVDC Charge for Region in Rs/month  [Approved Injection] / [Total Approved

Withdrawal of the Withdrawal DIC and Approved Injection of the Generator having

LTA to target Region]

For Demand:

[HVDC Charge for Region in Rs/month]  [Approved Withdrawal] / [Total

Approved Withdrawal of the Withdrawal DIC and Approved Injection of the

Generator having LTA to target Region]

(ii) HVDC Charge shall also be applicable for additional MTOA. Over/under

recovery of HVDC charges shall be adjusted in the third part of bill in a manner as

provided in Regulation 11(6) of these Regulations.

(iii) Where transmission charges for any HVDC system are to be partly borne by a

DIC (injecting DIC or withdrawal DIC, as the case may be) under a PPA or any

other arrangement, transmission charges in proportion to the share of capacity in

accordance with the PPA or other arrangement shall be borne by such DIC and the

charges for balance capacity shall be borne by the remaining DICs by scaling up of

MTC of the AC system included in the PoC. Such HVDC shall not be considered

under (i) above.

This first part of the bill shall be raised based on the Point of Connection rates,

Reliability Support rate, HVDC Charge, Approved Withdrawal and Approved

Injection for each DIC, provided by the Implementing Agency on the next working

day of uploading of the Regional Transmission Accounts by the respective Regional

859
 Sharing of Inter-State Transmission Charges Regulations, 2010

Power Committees on their websites in each month for the previous month and

determined prior to the commencement of the application period:

Provided that the list of transmission assets along with the approved transmission

charges for which billing has been done shall be enclosed with the first part of the

bill:

Provided further that the charges for the DICs having long term access without

beneficiaries shall comprise the Injection POC Charges, Reliability Support Charges

and HVDC Charges.]49

[(5) The second part of the bill shall be raised to recover charges for Additional Approved

Medium Term Open Access which shall be computed as follows:

For Demand:

PoC Transmission rates for demand zone in Rs/ MW / month  Approved

Additional Medium Term Withdrawal

The second part of the bill shall be raised on the DICs alongwith the first part of the

bill:

Provided that the revenue collected from the approved additional Medium-term

injection, which has not been considered in the Approved Injection/Approved

Withdrawal, shall be reimbursed to the DICs having Long-term Access in the

following month, in proportion to the monthly billing of the respective month:

49
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

860
 Sharing of Inter-State Transmission Charges Regulations, 2010

Provided further that the Withdrawal PoC charges for Medium-term Open Access to

any region shall be adjusted against Injection PoC charges for the Long-term Access

to the target region without identified beneficiaries:

Provided also that a generator who has been granted Long-term Access to a target

region shall be required to pay PoC injection charge for the remaining quantum after

offsetting the quantum of Medium-term Open Access:

Provided also that where a generator is liable to pay withdrawal charges for the

specified quantum as per the terms of any MTOA contract, then injection charges for

same quantum of power shall be offset against LTA granted.]50

(6) The third part of the bill shall be used to adjust any variations in interest rates, FERV,

rescheduling of commissioning of transmission assets, etc. as allowed by the

Commission for any ISTS Transmission Licensee. Total amount to be recovered /

reimbursed because of such under recovery / over recovery shall be billed by CTU to

each Designated ISTS Customer in proportion of its average Approved Injection /

Approved Withdrawal over previous six months on a biannual basis. This part of the

bill shall be raised on first working day of September and first working day of March

for the previous six months.

(7) Deviations shall be billed separately by the CTU. This bill shall charge the Designated

ISTS Customer s for deviations from the sum of the Approved Withdrawal, Approved

Additional Medium Term Withdrawal and Approved Short Term Withdrawal (MW)

50
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

861
 Sharing of Inter-State Transmission Charges Regulations, 2010

or Approved Injection, Approved Additional Medium Term Injection and Approved

Short Term Injection (MW). This part of the bill shall be computed as:51

For Generators:

In case Average MW injected during time block of positive deviation is

greater the sum of Approved Injection, Approved Additional Medium

Term Injection and Approved Short Term Injection, then for the first 20%

deviation, transmission charges shall be at the zonal Point of Connection

charges for the generation zone.

For deviation beyond 20%, the additional transmission charges shall be

1.25 times the zonal Point of Connection charges for the generation zone.

In case a generator instead of injecting, withdraws from the grid, the additional

transmission charges shall be computed as

1.25  PoC Transmission [rates ] for the demand zone in Rs / MW / time block 
 Average MW Withdrawal during time blocks of such negative deviation 

For Demand:

In case Average MW withdrawal during time block of positive deviation is greater

the sum of Approved Withdrawal, Approved Additional Medium Term

Withdrawal and Approved Short Term Withdrawal, then for the first 20%

deviation, transmission charges shall be at the zonal Point of Connection charges

for the demand zone.

51
In the formulas under clauses 4, 5 & 7, the word “charge” was replaced by “rates” vide Amendment
Regulations 2012 w.e.f 29.03.2012

862
 Sharing of Inter-State Transmission Charges Regulations, 2010

For deviation beyond 20%, the additional transmission charges shall be 1.25 times

the zonal Point of Connection charges for the demand zone.

In case a withdrawing DIC becomes a net injector the additional transmission

charges shall be computed as

1.25  PoC Transmission [rates ] for the generation zone in Rs / MW / time block 
 Average MW Injected during time blocks of such negative deviation 

[This bill shall be raised by the CTU within 3 (three) working days of the issuance of

the Regional Transmission Deviation Account by the RPCs:

Provided that the agency of the State responsible for the intimation of deviation on

account of Unscheduled Interchange energy shall be the agency responsible for the

intimation of deviation on account of the transmission usage to the respective RPCs,

for inclusion of the same in their Regional Transmission Deviation Account (RTDA):

Provided further that the revenue collected against the Bill for Deviation from DICs in

the synchronously connected grid shall be reimbursed to the DICs in the same

synchronously connected grid having Long-term Access, in the following month, in

proportion to the monthly billing of the respective month.]52

(8) [ ]53

(9) The governance of the Short Term Open Access Transactions shall be as per the

Central Electricity Regulatory Commission (Open Access in inter-State Transmission)

Regulations, 2008 and as amended by the Commission from time to time with the

exception that the Transmission Charges for Short Term Open Access Transactions

shall be the Zonal Point of Connection charges as determined by these regulations.

52
Substituted vide First Amendment Regulations, 2011, w.e.f. 25.11.2011
53
Deleted vide First Amendment Regulations, 2011, w.e.f. 25.11.2011

863
 Sharing of Inter-State Transmission Charges Regulations, 2010

[Provided that the DICs which were granted LTA to a target region and are paying

injection charges for Long Term Access, the injection PoC Charges and Demand PoC

Charges paid for Short Term Open Access to any region shall be adjusted in the

following month against the monthly injection PoC Charges for Approved injection:

Provided further that a generator, who has been granted Long-term Access to a target

region, shall be required to pay PoC injection charge for the Approved injection for

the remaining quantum after offsetting the charges for Medium-term Open Access,

and Short-term open access:

Provided also that the injection PoC charge/Withdrawal PoC charges for Short-term

open access given to a DIC shall be offset against the corresponding injection PoC

charges or Withdrawal PoC charges to be paid by the DICs for Approved

injection/Approved withdrawal corresponding to Net withdrawal (load minus own

injection) considered in base case:

Provided also that for withdrawal DIC, this adjustment is given only for STOA

transaction by DIC and not applicable to other intra-State entity embedded in State

and engaged in STOA:

Provided also that this adjustment shall also be allowed for collective transactions.

Generators who are granted LTA to a target region shall be given adjustment

corresponding to injection charges and withdrawal DICs shall be given adjustment

corresponding to withdrawal charges:

864
 Sharing of Inter-State Transmission Charges Regulations, 2010

Provided also that this adjustment shall not be allowed for collective transactions and

bilateral transactions carried out by any trading licensee, who has a portfolio of

generators in a State for which LTA was obtained to a target region.]54

12. Collection.

(1) The CTU shall collect charges on account of the first part of the bill as computed in

accordance with Regulation 11(4) of these Regulations on behalf of the ISTS service

providers and thereafter redistribute the same to Transmission Licensees in the ISTS

in proportion to their respective Monthly Transmission Charges;

(2) The CTU shall collect charges on account of the second part of the bill as computed in

accordance with Regulation 11(5) of these Regulations and thereafter distribute the

same to Transmission Licensees in the ISTS in proportion to their respective Monthly

Transmission Charges. This amount along with the interest thereon shall be adjusted

in the Yearly Transmission Charge (to be used for the computation of Point of

Connection charges) of the respective transmission licensee for the next financial

year;

(3) The CTU shall collect charges on account of the third part of the bill as computed in

accordance with Regulation 11(6) of the section on Billing of these Regulations and

thereafter transfer the same to respective ISTS Transmission Licensees for whom this

adjustment bill is required;

(4) The CTU shall collect charges on account of the fourth part of the bill as computed in

accordance with Regulation 11(7) of these Regulations and thereafter distribute the

54
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

865
 Sharing of Inter-State Transmission Charges Regulations, 2010

same to Transmission Licensees in the ISTS in proportion to their respective Monthly

Transmission Charges. This amount along with the interest thereon shall be adjusted

in the Yearly Transmission Charge (to be used for the computation of Point of

Connection charges) of the respective transmission licensee for the next financial

year;

(5) The payment by various Designated ISTS Customer s and disbursement to various

ISTS Licensees and the owners of Deemed Inter State Transmission System shall be

executed through RTGS.

(6) Every Designated ISTS Customer shall ensure that the charges payable by them are

fully discharged within the time-frame specified in the Transmission Service

Agreement or the amended Bulk Power Transmission Agreements. Disputes, if any

shall be resolved as per the provisions of the Transmission Service Agreement or the

amended Bulk Power Transmission Agreement s as specified in Chapter 6 of these

regulations.

(7) Delayed payment in a month by any Designated ISTS Customer shall result is pro-

rata reduction in the payouts to all the ISTS Licensees and other non-ISTS Licensees

whose assets have been certified as being used for interstate transmission by the

RPCs.

(8) Designated ISTS Customers shall provide payment security as determined through

detailed procedures developed by the CTU. The level of such payment security shall

be related to the Approved Withdrawal or Approved Injection.

(9) CTU shall prepare a detailed procedure for Billing, Collection and Disbursement and

present the same to the Commission for approval within 30 days of the notification of

these regulations.

866
 Sharing of Inter-State Transmission Charges Regulations, 2010

CHAPTER 6: COMMERCIAL AGREEMENTS

13. Transmission Service Agreement (TSA).

(1) The Designated ISTS Customers and the CTU shall enter into new transmission

services agreement or modify the existing Bulk Power Transmission Agreements to

incorporate the new tariff and related conditions. Such agreement shall govern the

provision of transmission services and charging for the same and shall be called the

Transmission Service Agreement (TSA) and shall, inter-alia, provide for:-

(a) Detailed commercial and administrative provisions relating to sharing of ISTS

charges and losses based on principles derived from these regulations;

(b) Provisions on metering, accounting, billing and recovery of charges for the

ISTS from the constituents;

(c) Procedures for declaration and approval of contracted capacity at each node or

an aggregation of nodes in the ISTS for each Designated ISTS Customer;

(d) Detailed procedures and provisions for connection by the Designated ISTS

Customer s at the inter-connection points, including the processes for

requisitioning new inter-connection capacity on the ISTS;

(e) Procedures and provisions for treatment of over or under injections by the

Designated ISTS Customers;

(f) Procedures and provisions for treatment of the delay in injection / withdrawal

by Designated ISTS Customers;

(g) Treatment of the delay in commissioning of transmission lines;

(h) Payment security mechanisms;

(i) Default and its consequences;

867
 Sharing of Inter-State Transmission Charges Regulations, 2010

(j) Dispute resolution mechanisms;

(k) Term of the agreement and the termination provisions;

(l) Force Majeure Conditions; and

(m) Any other matter that is relevant for the Point of Connection transmission

charge and loss allocation mechanism.

(2) Within 30 days of notification of these regulations, the CTU shall publish the draft

Model Transmission Service Agreement on its website and invite public comments on

the same.

(3) The CTU shall, after duly considering the public comments, submit the draft Model

Transmission Service Agreement to the Commission for its approval within 60 days

of the notification of these regulations.

(4) The final version of the Model Transmission Service Agreement, as approved by the

Commission, shall be notified and used as the base transmission service agreement by

the ISTS Licensees.

(5) The notified Model Transmission Service Agreement shall be the default transmission

agreement and shall mandatorily apply to all Designated ISTS Customers.

(6) The Transmission Service Agreement may have separate provisions for long term,

medium term and short term access to the ISTS.

(7) Signing of the Transmission Service agreement shall not be a pre-condition for

construction of new network elements by the CTU and Transmission Licensees,

provided that such network construction is undertaken after due approval of the

Commission.

868
 Sharing of Inter-State Transmission Charges Regulations, 2010

(8) The Transmission Service Agreement may have aspects that are amended from time

to time by the signatories without the entire agreement being replaced or being

rendered infructuous. Such aspects may include the contracted capacity, commercial

terms, and reliability requirements, if any. Change of such terms shall be guided by

the technical configuration and capabilities of the power system.

(9) The CTU shall enter into a separate Revenue sharing agreement with other ISTS

transmission licensees to disburse monthly transmission charges among various

transmission licensees. The impact of any delayed payment / non-payment by any

Designated ISTS Customer shall be shared pro-rata in proportion of their Yearly

Transmission Charge by all the transmission licensees including the CTU. The CTU

shall submit the Revenue Sharing Agreement within 30 days of the notification of

these regulations for approval by the Commission.

14. Amendment of existing contracts.

(1) All existing users of the ISTS and the Transmission Licensees shall ensure that their

existing contracts are realigned to these regulations within a period of 60 days from

the date of notification of the Transmission Service Agreement insofar as the

elements related to determination of Point of Connection transmission charges,

allocation of losses, billing and collection, provision of information, and any other

matter that requires amendment or realignment consequent to these regulations.

15. Transition Period/Mechanism.

(1) The Commission shall notify detailed procedures as proposed by the Implementing

Agency, NLDC and the CTU to be followed under these regulations, along with

869
 Sharing of Inter-State Transmission Charges Regulations, 2010

corresponding timelines, as far as possible within 3 (three) months from the

notification of these regulations. Such Procedures shall include:-

(a) Procedures for provision of information by Designated ISTS Customers and

other constituents as prepared by Implementing Agency and approved by the

Commission;

(b) Procedures to be followed by the Implementing Agency for computation of

charges as prepared by Implementing Agency and approved by the

Commission;

(c) Procedures for sharing of losses according to the methodology set out in these

Regulations as prepared by NLDC and approved by the Commission;

(d) Procedures for Billing and collection of charges by the CTU on behalf of the

Transmission Licensees and redistribution of the same (including amounts

over or under collected) as prepared by the CTU and approved by the

Commission; and

(e) Payment and payment security related procedures as prepared by the CTU and

approved by the Commission.

(2) The Implementing Agency shall ensure smooth transition to the new mechanism and

shall take necessary steps to disseminate information and build capacity among the

Designated ISTS Customer s and the ISTS Licensees.

870
 Sharing of Inter-State Transmission Charges Regulations, 2010

CHAPTER 7: INFORMATION PROCEDURES

16. Provision of information by Designated ISTS Customers and other constituents.

(1) On or before [at least 45 days prior to the beginning of the application period]55, each

Designated ISTS Customer whose network forms a part of the Basic Network, ISTS

licensee and owners of Deemed Inter State transmission systems whose charges are to

be recovered from Designated ISTS Customers, shall supply the Implementing

Agency with Basic Network details, Yearly Transmission Charge computations,

and any other information required by the Implementing Agency to compute the

transmission charges for allocation and apportionment as detailed in the Procedures

for provision of information by Designated ISTS Customers and other constituents

prepared by NLDC consequent to these Regulations.

(2) On or before [at least 45 days prior to the beginning of the application period]56, each

Designated ISTS Customer shall supply the Implementing Agency with its demand

or injection forecast for each season of the following Financial Year to enable the

Implementing Agency to use such demand and injection forecast as the basis for

calculation of the transmission charge and loss allocators for the period.

Provided that, if necessary, the information may be sought by the

Implementing Agency at times other than those indicated in regulation 16 (1) and 16

(2).

(3) Data to be submitted by CTU, owners of Deemed Inter State transmission systems

and Designated ISTS Customer s whose assets are used in the Basic Network:

55
Replaced vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
56
Replaced vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

871
 Sharing of Inter-State Transmission Charges Regulations, 2010

(a) In the first year of implementation: the entire network data including that

used for load flow analysis in the formats prescribed by the Implementing

Agency , line-wise / network element-wise Yearly Transmission Charge ;

(b) In the subsequent years: data and dates of commissioning of any new

transmission asset in the [next Application Period]57 and their Yearly

Transmission Charge approved by the Commission / provisional Yearly

Transmission Charge , based on Commission norms in case such Yearly

Transmission Charge is not approved by the Commission.

(4) Data to be submitted by Designated ISTS Customers connected to ISTS:

[(a) MW and MVAR Data for injection or drawal at various nodes or a group of

nodes shall be submitted for maximum injection/maximum withdrawal for

each application period. Such data shall include the power tied in long term

contracts and approved medium term open access agreements.]58

[ ]59.

(5) In the first year of the implementation of these regulations, the Designated ISTS

Customers and Transmission Licensees shall submit the Injection / Demand data,

network data and Yearly Transmission Charge data to the implementing agency

not later than 60 days of the notification of these regulations in formats provided by

Implementing Agency;

(6) In case, large changes in the Point of Connection charges are foreseen on account of

the network or its usage undergoing substantial change, the Implementing Agency

57
Replaced vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
58
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
59
Deleted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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may file a petition before the Commission, and undertake the revised computations

only upon issuance of the Commission‟s orders in this regard;

[17. Information to be published by the Implementing Agency

(1) The information to be provided by the Implementing Agency consequent to the

computations undertaken shall include:

(a) Approved Basic Network Data and Assumptions, if any;

(b) Zonal and nodal transmission charges for the ensuing Application Period;

(c) Zonal and nodal transmission losses data for the ensuing Application Period;

(d) Schedule of charges payable by each constituent for the ensuing Application

Period;

(e) YTC detail (Information submitted by the transmission licensees covered under

these Regulation and computation by Implementing Agency);

(f) Zone wise details of PoC Charges to enable each DIC to see details of transmission

lines it is using and whose transmission charges it is sharing;

(g) LTA /MTOA and their commencement schedule.]60

(2) Such information shall be made public by Implementing Agency after undertaking the

computations for the Application Period, and upon being approved by the

Commission.

60
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(3) To ensure maximum information disclosure, the Implementing Agency shall ensure

that the underlying network information and base load flows used are available on its

website.

CHAPTER 8: IMPLEMENTATION ARRANGEMENTS

18. Implementing Agency.

(1) Based on the Yearly Transmission Charge, the allocation of the ISTS Charges and

Losses shall be allocated by an entity authorised by the Commission for the purpose

and shall be designated as the Implementing Agency.

Provided that for the first two years of the notification of these regulations the

NLDC shall be the Implementing Agency.

(2) The Implementing Agency shall submit, for approval of the Commission, a detailed

procedure along with the data formats for obtaining data from Designated ISTS

Customers, ISTS Licensees and non-ISTS Licensees whose assets have been certified

by RPCs as being used for inter-state transmission, within 30 days of notification of

these regulations for the Implementation of the Point of Connection method,

guidelines for which have been detailed in the Annexure - I to these regulations.

(3) The Implementing Agency shall determine the allocation and sharing of transmission

charges and losses for each financial year, which may be differentiated on a seasonal

basis.

(4) The Implementing Agency shall be reimbursed the expenses incurred for the

computation of transmission charges (for the purpose of allocation and apportionment

thereof) as per Yearly Transmission Charges approved by the Commission. The

software for the implementation of transmission tariffs shall be audited by the

Commission before it is commissioned, and thereafter before any changes are made to
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the software or implementation methodology. The Software shall be made available to

Implementing Agency by the Commission;

CHAPTER 9: MISCELLANEOUS

19. Savings and Repeal.

(1) Save as otherwise provided in these regulations, Regulation 33 of the Central

Electricity Regulatory Commission (Terms and Conditions of Tariff)

Regulations, 2009, Regulation 16(1) and 16(2) of the Central Electricity

Regulatory Commission (Open Access in inter-State Transmission)

Regulations, 2008 are hereby repealed.

(2) Not withstanding such repeal, anything done or any action taken or purported

to have been done or taken under the repealed regulations shall be deemed to

have been done or taken under these regulations.

20. Power to Relax.

(1) The Commission may, for reasons to be recorded in writing, relax any of the

provisions of these regulations on its own motion or on an application made before it

by an interested person.

21. Power to Remove Difficulties

(1) If any difficulty arises in giving effect to any of the provisions of these Regulations,

the Commission, may by general or special order, direct the Implementing Agency,

NLDC, CTU, RLDC, RPC, ISTS Licensees and Designated ISTS Customers, to take

suitable action, not being inconsistent with the provisions of the Act, which appears to

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the Commission to be necessary or expedient for the purpose of removing the

difficulties.

(2) The Implementing Agency, NLDC, CTU, RLDC, RPC, ISTS Licensees and

Designated ISTS Customers may make an application to the Commission and seek

suitable orders to remove any difficulties that may arise in implementation of these

Regulations.

(3) Notwithstanding Sub-Regulations (1) and (2), if any difficulty arises in giving effect

to the provisions of these Regulations, the Commission may, by general or specific

order, make such provisions not inconsistent with the provisions of the Act, as may

appear to be necessary for removing the difficulty.

Sd/-

(Alok Kumar)

Secretary

Note: The Central Electricity Regulatory Commission (Sharing of inter-State Transmission

Charges and Losses) Regulations, 2010 were published in Part III, Section 4, No. 162 of the

Gazette of India (Extraordinary) dated 16.06.2010 and amended vide -

(a) First Amendment Regulations, 2011 published in Part III, Section 4, No. 229 of the

Gazette of India (Extraordinary) dated 25.11.2011.

(b) Second Amendment Regulations, 2012 published in Part III, Section 4, No. 76 of the

Gazette of India (Extraordinary) dated 29.03.2012.

(c) Third Amendment Regulations, 2015 published in Part III, Section 4, No. 118 of the

Gazette of India (Extraordinary) dated 07.04.2015.

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(d) Fourth Amendment Regulations, 2015 published in Part III, Section 4, No. 239 of the

Gazette of India (Extraordinary) dated 08.07.2015.

ANNEXURE-1

I. PHILOSOPHY OF POINT OF CONNECTION BASED TRANSMISSION PRICING

MECHANISM AND SELECTION OF THE HYBRID METHOD

Efficient pricing of a commodity or service needs to reflect the marginal cost of utilization of

the underlying resources that are used in the provision of that commodity or service. The

„operational‟ term here is ‘utilization‟. The pricing mechanism must therefore be able to

capture the utilization, and charge for the resources being utilized.

Utilization of the network is generally determined in terms of either average utilization or

marginal utilization of the transmission assets. Pricing of transmission services based on

average or marginal utilization of the network branches is known as Average Participation or

Marginal Participation method respectively. These two methods have been compared and

contrasted in detail in the literature. These methods are discussed in detail below.

1.1 MARGINAL PARTICIPATION METHOD

Any usage based methodology tries to identify how much of the power that flows through

each of the lines in the system is due to the existence of a certain network user, in order to

charge it according to the adopted measure of utilization. To do so, the marginal participation

method analyzes how the flows in the grid are modified when minor changes are introduced

in the production or consumption of agent i. For each of the considered scenarios (for each

season) the procedure can be considered as follows:

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a. Marginal Participation sensitivities Aij are obtained that represent how the flow in line

j changes when the injection in bus i is increased by 1 MW. The increase in 1 MW

has to be compensated by a corresponding increase in load or generation at some

other bus or buses – called the slack bus(es).

b. Total participations for each agent are calculated as a product of its net injection by its

marginal participation. If net injection is considered positive for generators and

negative for demands, the total participation of any agent i in line j is Aij(generationi –

demandi).

c. The cost of each line is allocated pro-rata to the different agents according to their

total participation in the corresponding line.

1.2 AVERAGE PARTICIPATION METHOD

The method of average participation works as follows:

1. For every individual generator i, a number of physical paths are constructed, starting

at the node where the producer injects the power into the grid, following through the

lines as the power moves through the network, and finally reaching several of the

loads in the system.

2. Similar calculations are also performed for the demands, tracing upstream the energy

consumed by a certain user, from the demand bus until some generators are reached.

One such physical path is constructed for every producer and for every demand.

3. In order to create such physical paths, a basic criterion is adopted: A rule allocates

responsibility for the costs of actual flows on various lines from sources to sinks

according to a simple allocation rule, in which inflows are distributed proportionally

between the outflows. The main attractions of tracing are that the rule has some

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theoretical backing based and does not require the choice of a slack node. The

drawbacks of tracing are first that aggregation of users can lead to counterintuitive

results: if generation and load or different nodes are aggregated, then they are exposed

to different tariffs. Second, the choice of the allocation rule is decisive but apparently

arbitrary. An illustrative example of the proportional allocation mechanism is

demonstrated in Fig.3 below.

Fig. 3: Average Participation Method

. 40
30   12
(60  40)

12 MW
40 MW
Total =
30
18 MW

28 MW
Total =
70
42 MW
60 MW

The average participation method calculates the participation of agent i by tracking the

influence in the network of a transit between node i and several ending nodes that result from

the rules that conform the algorithm. In the example above, based on flow in the outgoing

lines, the injection of 40MW (through the red line) is allocated to the outgoing lines in the

proportion of the transfers from the two outgoing lines. Thus the outgoing line that transfers

30 MW (i.e, 30% of the total transfer out of the bus) is allocated 30% of the 40 MW injection

from the red line, i.e., 12 MW. Similar allocations are made for the other flows as well.

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1.3 REASONS FOR ADOPTION OF THE HYBRID METHOD

The Marginal Participation method (with slight modifications to the above generic

framework) has been implemented in various countries including United Kingdom, Norway

(for transmission losses), Brazil, Columbia etc. There is however little international

experience in the use of the Average Participation Method. Further in the Indian context the

Hybrid Method – where the slack buses are selected by using the Average Participation

Method and the burden of transmission charges or losses on each node is computed using the

Marginal Participation Method was found appropriate because:

 The nodal transmission access charges in the AP method have a higher variance. A

compared to the range of transmission access charges in the Hybrid method (Rs 2.98

– 17.75 lakh / MW), the range in the AP method (Rs. 2.79 – 53.61 lakh / MW) is

much higher.

 Further, since Hybrid method takes into account all the incidental flows – which is the

reality of interconnected transmission networks – the Hybrid Method captures

network utilization much better than the AP method, which simply traces the path of

power from the origin to the sink(s) or vice-versa. Because of the ability of the Hybrid

method to consider incidental flows, the method captures network „utilization‟ better

than AP method – which is one of the objectives of the NEP.

To illustrate the above point further, consider the following network and the flows

indicated therein:

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Under Average Participation Method, tracing from generator at Node-A would lead to

the consideration of utilization of Line 2 for load 2 and Line 2 and Line 6 for load 1.

However, it can be seen from the above network diagram, that keeping the generation

at Node B constant, an increase in generation at Node A is expected to lead to an

increase in flow in Line 4, Line 5 and Line 3 (Flow in Line 1 will be from Node B to

Node A, as in the base case, but with an increase in generation at Node A, the

magnitude of flow will reduce). While the AP Method captures utilization of Line 2

and Line 6, it fails to consider the impact of generation at Node A on Line 4, Line 5

and Line 3. Application of the AP method, in this case, would lead to very low nodal

charges at Node A and high Nodal Charges at Node B and hence an inaccurate

estimation of line utilization. Application of the MP method, on the other hand, would

capture utilization better by attributing some percentage of utilization of Line 3, Line

4 and Line 5 to Node A.

Hybrid Method – a combination of the Average Participation and the Marginal

Participation Method, while considering the absorption of power generated at Node A

by Load 1 and Load 2 only (as determined using AP method), considers the utilization

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of Line 3, Line 4 and Line 5 also, as opposed to the consideration of only Line 2 and

Line 6, as in the pure AP method.

 The criticism of the MP method that the results are dependent on the choice of the

slack bus is obviated because of the revised method of selection of slack buses which

is based on the AP method.

2. PRICING MECHANISM UNDER SELECTED FRAMEWORK

As discussed in the previous sections, based on the review of the international experience, the

literature and the Indian system, the Hybrid method – a hybrid of the Marginal and Average

Participation Methods has been found to be most appropriate. The details of the hybrid

method are discussed in sections below. Following steps shall be followed in the

implementation of the Hybrid Methodology:

1. Data Acquisition

2. Computation of Load Flows on the Basic Network

3. Network Reduction

4. Identification of Slack Node(s)

5. Hybrid Methodology for the determination of transmission charges

6. Hybrid Methodology for the determination of transmission losses

7. Determination of Sharing of YTC and Losses

8. Creation of Zones

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2.1 DATA ACQUISITION: INPUTS TO THE MODEL

The transmission pricing model requires a set of inputs representative of [“maximum

injection/maximum withdrawal”]61 in each of the blocks of months as required by the Central

Electricity Regulatory Commission (Sharing of Inter State Transmission Charges and Losses)

Regulations, 2010 on the transmission system:

 Nodal generation information

 Nodal demand information

 Transmission circuits between these nodes and their electrical characteristics required

for load flow analysis, the associated lengths of these transmission lines and its

capacity, Yearly Transmission Charges (YTC) of each line

 Identification of a reference node (s)

[“2.1.1 NODAL GENERATION AND DEMAND INFORMATION

Data Required for Annual process of determination of transmission charges based on

Hybrid Methodology:

The DICs will provide forecast injection/withdrawal information {MW and MVAR (or an

assumption about the power factor to be used)} at all the nodes or a group of nodes in a zone

(identified a-priori by the Implementing Agency (IA) in the Network. “Typical”

injection/withdrawal data based on maximum injection/withdrawal as defined in these

regulations shall be provided to the Implementing Agency by the DICs for each of the

application period.

61
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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DICs shall also provide injection and withdrawal data for the corresponding quarter of last

three years. The data provided by the DICs shall be as per the formats prepared by the IA and

duly approved by the Commission under the relevant provisions of these Regulations.

Information provided by the DICs shall be vetted by the Implementing Agency as per the

provisions of the Regulations and Detailed procedure notified by Implementing Agency.

Methodology for calculation of forecasted maximum generation/withdrawal of DICs for

vetting by Implementing Agency

For Demand data:

The projected maximum withdrawal figures provided by DICs will be vetted by

Implementing Agency based on the following:

a. Monthly peak demand met for each State/UT in the last 3 years for the period

corresponding to the Application Period shall be considered.

b. The average of monthly peak demand met for each State/UT in each of the last 3

years for the period corresponding to the Application Period shall be calculated.

c. The average peak demand met for each State/UT for the Application Period shall

be projected based on last 3 year‟s average of monthly peak demand met figures.

d. Similarly All India peak demand met in last 3 years shall be averaged for the

period corresponding to the Application Period. This shall be projected for the

ensuing Application Period. The projected peak demand of each State/UT thus

arrived shall be normalized with the projected All-India peak demand met of the

Application Period under consideration for the current year.

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For Generation Data:

a. The projected maximum injection figures provided by DICs shall be vetted by the

Implementing Agency based on average of monthly maximum injection in the last 3

years (based on actual metered data available from RLDCs) for the period

corresponding to Application Period projected for the ensuing Application Period.

Similarly maximum injection data (for last 3 years as well as projected for the

ensuing quarter) for generators embedded within the State system shall be provided

by respective SLDC. In case data is not provided by SLDC to the Implementing

Agency, the maximum injection of the concerned State shall be taken as the

difference between peak met and withdrawal from ISTS based on actual metered

data (for the time block corresponding to the block in which peak met occurred).

b. If sum of projected generation in the grid is more than sum of projected demand,

the generation may be proportionately reduced to match sum of withdrawal data. If

sum of projected generation in the grid is less than sum of projected demand, the

demand may be proportionately reduced to match sum of generation.

c. The peak demand met figures in respect of each State/UT and All India peak met

shall be taken from the final/revised monthly power supply position published by

CEA.

d. The Implementing Agency shall finalize the data duly maintaining Load

Generation balance.

e. If the Validation Committee encounters any difficulty for validation of Approved

Injection or Approved Withdrawal or any other data on account of non-availability

or partial availability of any information from the DICs, the Validation Committee

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may adopt such method as may be considered necessary consistent with the

objectives of these regulations.

f. The data as validated/adopted by the Validation Committee shall be final.”]62

2.1.2 NETWORK DATA

CTU, owners of deemed ISTS transmission systems and the DICs whose assets are being

considered in the Basic Network shall supply the Network Data for the existing network, in

the format desired by the IA. The network data of the proposed network shall be supplied by

the CTU. The requirement below has been given in the illustrative PTI format. The data shall

inter-alia include:

(a) Bus Data

I - Bus number

1 - Load bus

2 - Generator or plant bus

3 - Swing bus

4 - Isolated bus

GL - Shunt conductance, MW at 1.0 per unit voltage

BL - Shunt susceptance, MVAR at 1.0 per unit voltage. (- = reactor)

IA - Area number

VM - Voltage magnitude, per unit

62
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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BASKV - Base voltage, KV

ZONE - Zone

(b) Generator data

I - Bus number

ID - Machine identifier

PG - MW output

QG - MVAR output

QT - Max MVAR

QB - Min MVAR

VS - Voltage setpoint

IREG - Remote controlled bus index (must be type 1), zero to control own voltage, and must

be zero for gen at swing bus

MBASE - Total MVA base of this machine (or machines)

ZR, ZX - Machine impedance, pu on MBASE

RT, XT - Step up transformer impedance, p.u. on MBASE

GTAP - Step up transformer off nominal turns ratio

STAT - Machine status, 1 in service, 0 out of service

RMPCT - Percent of total VARS required to hold voltage at bus IREG to come from bus I -

for remote buses controlled by several generators

PT - Max MW

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PB - Min MW

(c) Branch Data

I - From bus number

J - To bus number

CKT - Circuit identifier (two character)

R - Resistance, per unit

X - Reactance, per unit

B - Total line charging, per unit

RATEA - MVA rating A

RATEB, RATEC - Higher MVA ratings

RATIO - Transformer off nominal turns ratio

ANGLE - Transformer phase shift angle

GI, BI - Line shunt complex admittance for shunt at from end (I) bus, pu.

GJ, BJ - Line shunt complex admittance for shunt at to end (J) bus, pu.

ST - Initial branch status, 1 - in service, 0 - out of service

(d) Transformer Adjustment Data

I - From bus number

J - To bus number

CKT - Circuit number

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 Sharing of Inter-State Transmission Charges Regulations, 2010

ICONT - Number of bus to control. If different from I or J, sign of ICONT determines

control. Positive sign, close to impedance (untapped) bus of transformer. Negative sign,

opposite.

RMA - Upper limit of turns ratio or phase shift

RMI - Lower limit of turns ratio or phase shift

VMA - Upper limit of controlled volts, MW or MVAR

VMI - Lower limit of controlled volts, MW or MVAR

STEP - Turns ratio step increment

TABLE - Zero, or number of a transformer impedance correction table 1-5

(e) Area Interchange Data

I - Area number (1-100)

ISW - Area interchange slack bus number

PDES - Desired net interchange, MW + = out.

PTOL - Area interchange tolerance, MW

ARNAM - Area name, 8 characters, enclosed in single quotes.

(f) DC Line Data

Each DC line has three consecutive records

I,MDC,RDC,SETVL,VSCHD,VCMOD,RCOMP,DELTI,METER

IPR,NBR,ALFMAX,ALFMN,RCR,XCR,EBASR,TRR,TAPR,TPMXR,TPMNR,TSTPR

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IPI,NBI,GAMMX,GAMMN,RCI,XCI,EBASI,TRI,TAPI,TPMXI,TPMNI,TSTPI

I - DC Line number

MDC - Control mode 0 - blocked 1 - power 2 - current

RDC - Resistance, ohms

SETVL - Current or power demand

VSCHD - Scheduled compunded DC voltage, KV

VCMOD - Mode switch DC voltage, KV, switch to current control mode below this

RCOMP - Compounding resistance, ohms

DELTI - Current margin, per unit of desired current

METER - Metered end code, R - rectifier I - Inverter

IPR - Rectifier converter bus number

NBR - Number of birdges is series rectifier

ALFMAX - Maximum rectifier firing angle, degrees

ALFMN - Minimum rectifier firing angle, degrees

RCR - Rectifier commutating transformer resistance, per bridge, ohms

XCR - Rectifier commutating transformer reactance, per bridge, ohms

EBASR - Rectifier primary base AC volts, KV

TRR - Rectifier transformer ratio

TAPR - Rectifier tap setting

TPMXR - Maximum rectifier tap setting

TPMNR - Minimum rectifier tap setting

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TSTPR - Rectifier tap step

Third record contains inverter quantities corresponding to rectifier quantities above.

(g) Switch Shunt Data

I - Bus number

MODSW - Mode 0 - fixed 1 - discrete 2 - continuous

VSWHI - Desired voltage upper limit, per unit

VSWLO - Desired voltage lower limit, per unit

SWREM - Number of remote bus to control. 0 to control own bus.

VDES - Desired voltage setpoint, per unit

BINIT - Initial switched shunt admittance, MVAR at 1.0 per unit volts

N1 - Number of steps for block 1, first 0 is end of blocks

B1 - Admittance increment of block 1 in MVAR at 1.0 per unit volts.

N2, B2, etc, as N1, B1

[2.1.3 YEARLY TRANSMISSION CHARGES:]63

[The line-wise YTC of the entire network shall be provided by the Transmission Licensees.

In case a line is likely to be commissioned during the Application Period, the data in respect

of the same, along with the anticipated COD will be provided by the CTU/ Transmission

Licensee to the Implementing Agency.

63
Inserted vide Second Amendment Regulations, 2012. w.e.f. 29.03.2012

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 Sharing of Inter-State Transmission Charges Regulations, 2010

For the determination of the transmission charges based on Hybrid Methodology applicable

in the next Application Period, all the above data shall be provided to the Implementing

Agency as per the timelines specified by the Implementing Agency.

Overall charges to be allocated among nodes shall be computed by adopting the YTC of

transmission assets of the ISTS licensees, deemed ISTS licensees and owners of the non-

ISTS lines which have been certified by the respective Regional Power Committee (RPC) for

carrying inter-State power. The Yearly Transmission Charge, computed for assets at each

voltage level and conductor configuration in accordance with the provisions of these

regulations shall be calculated for each ISTS transmission licensee based on indicative cost

provided by the Central Transmission Utility for different voltage levels and conductor

configuration. The YTC for the RPC certified non-ISTS lines which carry inter-State power

shall be approved by the Appropriate Commission.

In case line-wise tariff for the RPC certified non-ISTS lines has not been specified by the

Appropriate Commission, the tariff as computed for the relevant voltage level and conductor

configuration shall be used. The methodology for computation of tariff of individual asset

shall be similar to the methodology adopted for the ISTS transmission licensees and shall be

based on ARR of the STU as approved by the respective State Commission.

Certification of non-ISTS lines carrying inter-State power, which were not approved by the

RPCs on the date of notification of the Central Electricity Regulatory Commission (Sharing

of Transmission Charges and Losses) Regulations, 2009, shall be done on the basis of load

flow studies. For this purpose, STU shall put up proposal to the respective RPC Secretariat

for approval. RPC Secretariat, in consultation with RLDC, using WebNet Software would

examine the proposal. The results of the load flow studies and participation factor indicating

flow of Inter State power on these lines shall be used to compute the percentage of usage of

these lines as inter State transmission. The software in the considered scenario will give
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 Sharing of Inter-State Transmission Charges Regulations, 2010

percentage of usage of these lines by home State and other than home State. For testing the

usage, tariff of similar ISTS line may be used. The tariff of the line will also be allocated by

software to the home State and other than home State. Based on percentage usage of ISTS in

base case, RPC will approve whether the particular State line is being used as ISTS or not.

Concerned STU will submit asset-wise tariff. If asset wise tariff is not available, STU will

file petition before the Commission for approval of tariff of such lines. The tariff in respect of

these lines shall be computed based on Approved ARR and it shall be allocated to lines of

different voltage levels and configurations on the basis of methodology which is being done

for ISTS lines.]64

[2.2 COMPUTATION OF LOAD FLOWS ON THE BASIC NETWORK

The Implementing Agency shall run AC load flow on the Basic Network using the technical

data obtained from the DICs, SLDCs, RLDCs and NLDC. The real power generation at the

generator nodes in the Basic Network shall be based on maximum injection of the generators

connected directly to the ISTS or the injection submitted by the DICs, where such nodes are

embedded in the networks of the DIC. The demand at the load nodes shall be based on the

maximum demand met of the DICs. In the case of an STU / SEB, the total injection at all the

generator nodes owned by the STU/SEB shall be equal to the aggregate of injection of the

entities connected in the state network. Similarly, the withdrawal at all the nodes owned by

the SEB/STU shall be equal to withdrawal of all the entities connected in the SEB / STU

network.

In the process of convergence of the Load Flow on the Basic Network, the IA may require to

make certain adjustments in the load/generation at various buses to ensure load generation

64
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

balance. Such load flow analysis shall be performed for all the network conditions as required

by the Regulations in force. The entire process of formation of the Basic Network and

convergence to load flows shall be validated by the Validation Committee.]65

[ ]66

2.4 IDENTIFICATION OF THE SLACK NODES: USING AVERAGE PARTICIPATION METHOD

Rationale for Hybridization of the Marginal Participation and the Average Participation

Methods

Due to the Kirchoff‟s laws, any 1 MW increase in generation (or load) at node i has to be

compensated by a corresponding increase in load (or generation) at some other node or

nodes. Thus the calculation of how much an injection (or withdrawal) at a certain bus affects

the flows in the network depends on the choice of the node (s) that responds.

Different choices are possible for this „slack bus‟ (the responding node in power systems

terminology). In cases of countries like Argentina or Chile, the „slack node‟ is near the major

load centre. For larger networks, distributed slack nodes can be considered – where the

demand (generation) at all / pre-selected nodes responds pro-rata to 1 MW increment in

generation (load). For the purposes of the computations in the Indian context distributed slack

nodes have been considered. The selection of slack buses influences the final results

prominently and therefore is a decision which must not be made arbitrarily.

65
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
66
Deleted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

The method considered here is a hybrid of the marginal and the average participation

methods, and is sympathetic with the concerns of those who, in the defense of the interests of

their states argue that demand in each state must first be met by the generation within the

state and that the mismatches between the state generation and demand will result in export

or import flows.

Truncation at the 400 kV level also allows relation of local generation and local demand and

obtains a source (or a sink) for the net imports (or exports). In other words, state generators

below 400 kV are primarily linked with state demand and only net imports or exports are

linked with external nodes. The external slack bus (es) for each node shall be found as

follows:

a. For every node in a particular scenario, Average Participation method will be applied

to each generation / load located in the state under consideration. Tracing from load to

generator (or from generator to load), a set of generators (or loads) (including those

outside the state) and their contribution to the load (generator) is determined for each

load (generator) bus.

b. Using the above choice of slack buses for each generator and load bus, marginal

participation of each generator and load in each transmission line is computed.

2.5 COMPUTATION: HYBRID METHOD FOR THE DETERMINATION OF TRANSMISSION

CHARGES

Any usage based methodology attempts to identify how much of power that flows through

each of the lines in the system is due to the existence of a certain network user, in order to

charge it according to the adopted measure of utilization. To do so, the Hybrid Method

analyzes how the flows in the grid are modified when minor changes are introduced in the

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production (or consumption) of agent i, and it assumes that the relationship of the flow

through line j with the behaviour of the agent i can be considered to be linear. For each of the

considered blocks of months and [ ]67, the procedure can be described as follows:

1. Marginal participation sensitivities are obtained that represents how much the flow

through each network branch j increases when the injection/ withdrawal in a bus is

increased by 1 MW. Flow variation in each network branch j incurred by 1 MW

injection / withdrawal at each bus is computed for each scenario, e.

2. Due to the Kirchoff‟s laws, any 1 MW increase in generation (or load) at node i has to

be compensated by a corresponding increase in load (or generation) at some other

node or nodes (after adjusting for incremental system losses). Thus the calculation of

how much an injection (or withdrawal) at a certain bus affects the flows in the

network depends on the decision of which is the node that responds, and the answer

that is demanded from the method is heavily conditioned by an assumption that it

needs as an input. The methodology used for the selection of the distributed slack

buses is explained above.

3. Once the flow variation in each line incurred by each agent [ ]68 is obtained, it is

possible to compute a [ ]69 usage index for each network user. This index is

computed according to equation given below. It can be seen that only positive

increments in the direction of the power flow in the base case are considered. This

implies that increments which reduce burden on lines are neither given any credit nor

charged for use of the system. This is essentially because of practical reasons where it

67
Deleted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
68
Deleted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
69
Deleted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

could be difficult to pay grid connected entities for being connected to the grid.

Further, there could be times (with strictly positive chance) when these entities need

to use certain network branches along the direction of the main flow, though such

times may not be the times which coincide with [maximum injection/ maximum

withdrawal]70 considered in the load flow studies. This is also a standard international

practice followed in countries where such pricing mechanisms are used.

The []71 index (for each block of months) is computed as:

U e,i,l  ( Flei  Fle ).Pie .

Flei  Fle 0, Sign( Flei ) is same as Sign( Fle )

Where,

Ueil is the seasonal usage index in line l due to injection / withdrawal at node i

Fle is the flow in line l under scenario e under base case

File is the flow in line l under scenario e due to injection / withdrawal of 1 MW at

node

Pie is power dispatch / demand at bus i under scenario e under base case

4. The revenue requirement of each line is allocated pro-rata to the different agents

according to their total participation in the corresponding line.

U eil
Cost Allocated eil   Cl
U eil
i

Where,

70
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
71
Deleted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

Cl is the Transmission Charge of the line – computed by attributing the Yearly

Transmission Charge for the ISTS licensee to each line owned by it and to the block

of month under consideration

U eil
is the marginal participation factor
U eil
i

The above mechanism is also commonly referred to as the “Point tariff” and has been

considered by the CERC in the past as a potential alternative to the regional postage stamp

method.

2.6 COMPUTATION: HYBRID METHOD FOR THE SHARING OF TRANSMISSION LOSSES

1. In the application of the Marginal Participation Method for the allocation of

transmission losses to various nodes in the system, the change in losses in the system

(above the base case) because of a incremental injection / withdrawal at each node are

computed. The change in overall system losses per unit of injection / withdrawal at

each node is termed as the Marginal Loss Factor for that node. The marginal loss

factor shall be based on the following formula:

 System Losses
M arg inal Loss Factori   Ki
 Power generation / load at Node i

2. The selection of the slack buses for absorption (supply) of the incremental injection

(withdrawal) is done as per the methodology discussed above.

3. The marginal loss factors are multiplied by the generation / demand at these nodes

under base case, i.e.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

K i  Pi g for generation nodes

Kj P j
d
for demand nodes

Pi g is base case generation at node i

Where,
Pjd is base case demand at node j

4. Loss Allocation Factor for generation and demand nodes are computed by:

K i  Pi g
for generation node i and
 K i  Pi g   K j  Pjd
i j

K j  Pjd
for demand node j
K
i
i  Pi g   K j  Pjd
j

5. The Loss Allocators computed above are multiplied by the total system losses to

allocate losses to each node in the system.

2.7 COMPUTATION: DETERMINATION OF SHARING OF YTC AND TRANSMISSION LOSSES

The simulations will be carried out by the IA by using a software duly approved by the

CERC.

The following steps shall be followed:

[1. Converged AC Load Flow data for the all India Grid shall be used directly for the

implementation of the Hybrid Methodology.]72

72
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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2. [Treatment of HVDC: Flow on HVDC systems is regulated by power order and remains
constant for marginal change in load or generation. Hence, marginal participation (MP) of
HVDC systems is zero. Since the HVDC systems were specifically set up for transfer of bulk
power to specific Region, the DICs of the Region shall share the cost of HVDC systems.
HVDC system also helps in controlling voltages and power flow in inter-regional lines and
some benefits accrue to all DICs by virtue of HVDC system. Accordingly, 10 % of the MTC
of these systems be recovered through Reliability Support Charges. The balance amount shall
be payable by Withdrawal DICs of the Region in proportion to their Approved Withdrawal.
In case of Injection DICs having Long Term Access to target region, it shall be payable in
proportion to their Approved Injection.
Where transmission charges for any HVDC system line are to be partly borne by a DIC
(injecting DIC or withdrawal DIC, as the case may be) under a PPA or any other
arrangement, transmission charges in proportion to the share of capacity in accordance with
PPA or other arrangement shall be borne by such DIC and the charges for balance capacity
shall be borne by the remaining DICs by scaling up of YTC of the AC system included in the
PoC.]73
3. Using AC load flow, marginal participation factors shall be computed for

determination of transmission system utilization due to marginal injection /

withdrawal at each generator / demand node.

4. YTC for each line shall be based on the line-wise YTC provided by the Transmission

Licensees. Average per km YTC for each voltage level (and line configuration viz.,

400 KV D/C twin Moose, 400 kV Quad Moose, 400 kV Quad Bersimis etc.) of the

transmission licensee lines shall be applied to the 765 kV, 400 kV, 220 kV and 132

kV lines considered in the network.

[5. Hybrid Methodology shall be applied to Application Period.]74

[6. Annual Average YTC of each line will then be attributed to maximum

injection/maximum withdrawal.]75

73
Substituted vide Second Amendment Regulations, 2012. w.e.f. 29.03.2012
74
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.
75
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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7. The annual average YTC (of each period in each season) of each line is attributed to

the total change in flow in each line. Therefore the YTC is allocated to each agent in

proportion of the change in the flow in network branch affected by that agent.

8. Transmission [rates]76 based on Hybrid Methodology in Rs/MW/Month and

Rs/MW/hr at each node in each block of months will be computed.

9. Loss Allocators shall also be computed along with the above simulations and as

discussed above.

10. Total losses shall be computed, as per the present methodology, viz.,

The total net drawal by each utility is subtracted from the sum of net injection of

Inter-State Generating Stations (ISGS) and the inter-regional injections to arrive at the

losses in MWh.

All loss computations are on a weekly basis from the Special Energy Meters (SEMs)

installed at all inter-utility exchange points in the region. A week for the purpose of

accounting is from 0000 hours of Monday to 2400 hours of the following Sunday.

11. Using the loss allocators, the losses shall be allocated to each node, as per the detailed

procedure to be developed by NLDC under these Regulations.

[12. There shall be slabs for the percentage transmission losses in the All India grid till

such period the Commission may consider appropriate.]77

76
Substituted vide Second Amendment Regulations, 2012. w.e.f. 29.03.2012

77
Sub para 12 was initially added vide Second Amendment Regulations, 2012 and later substituted vide Third
Amendment Regulations, 2015 w.e.f. 01.05.2015.

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2.8 CREATION OF ZONES AND DETERMINATION OF ZONAL CHARGES AND LOSSES

The proposed mechanism is based on a locational point [rate]78 (Rs/MW/month) of

[(Paisa/unit)]79 for each grid connected entity, which entitles it to access the entire network.

In practice it is indeed cumbersome from an implementation perspective in view of the large

size of the Indian power system. In some instances it may be inappropriate to apply the

pricing at each node in the network since certain local peculiarities could distort pricing

signals. Hence a logical basis for aggregating the charges in a region into zones is necessary.

The principles of zoning of such charges are articulated in the Regulations.

2.8.1 DETERMINATION OF LOCATIONAL CHARGES IN GENERATION ZONES

[The transmission access rates shall be determined for each generation zone by computing the

weighted average of nodal access charges at each generation node in this zone.

The weighted average transmission access [rate] for nodes in a zone is the zonal transmission

access [rate] based on Hybrid Methodology for generation, e.g. in a Zone - ZZ, the following

three nodes were considered in one zone: PP, AA and KK.

Node Transmission Approved Injection/ Zonal Transmission

Charges Withdrawal* Rate
(`/Month) ( MW) (`/MW/Month)

PP 45, 00, 000 250 70, 000

AA 50, 00, 000
KK 80, 00, 000
ZZ – Zone 1, 75, 00, 000 250

78
Word “charge” was replaced by the word “rate” vide Second Amendment Regulations, 2012. w.e.f.
29.03.2012
79
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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 Sharing of Inter-State Transmission Charges Regulations, 2010

*Approved Injection/ Approved withdrawal (MW) shall be the Long-term Access plus

Medium Term Open Access i.e. Zonal PoC Charge computed considering maximum

injection /maximum withdrawal shall be divided by LTA +MTOA to arrive at PoC Rate. The

PoC rates shall be further grouped under slabs in accordance with sub-clause (l) of clause (1)

of Regulation 7.]80

[2.8.1.a. Methodology for calculation of PoC rates and billing of POC charges

(i) PoC rates for billing towards LTA/MTOA shall be calculated only on Withdrawal

nodes (as Withdrawal charges) and for generators who have Long Term Access to

target region (as injection charges) corresponding to untied power. PoC rates shall

not be calculated for ISGS with identified long term customers/ beneficiaries with

whom PPA have been signed.

Example for billing a Generator who have LTA to target region:

Suppose a Generator "A" has LTA of 900 MW to target region (WR-500 MW, NR-

400 MW).He ties up 150 MW of power with U.P through PPA. "A" shall be billed

for 500+250 =750 MW as its LTA to target region.

(ii) If any generator has contractual liability to pay the Withdrawal Charges of drawee

entity, then drawee DIC shall inform CTU and bill shall be raised by the CTU to

generator directly. In such a case, only withdrawal charges shall be payable by

generator for corresponding quantum of power.

(iii) For balance injection i.e. difference between Approved Injection and Quantum of

withdrawal, generator shall pay Injection Charges only.

(iv) For the purpose of STOA, collective transactions and computation of transmission

80
Substituted vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015

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deviation charges, POC injection rate / withdrawal rate for all DICs shall be

determined separately and shall be declared in paise/kWh

(v) The injection and withdrawal rates in paise/kWh as at (iv) above shall be computed

before transferring injection charges of ISGS having long term customers on

withdrawal DICs.

2.8.1.b. Methodology for calculation of Slab Rates

(i) The PoC rates shall be arrived at by dividing the quantum of charges allocated to each

zone by its LTA+MTOA.

(ii) The PoC rates so arrived shall be adjusted based on average rate and one sigma

deviation on either side. The difference between maximum rate and minimum rate so

arrived shall be divided by eight to determine width of each slab. The POC rates for

all entities shall be placed in appropriate slab, minimizing the distance from slab rate

as per its adjusted rate calculated after accounting for standard deviation. The rates

may be scaled up/down as required.

(iii) For the purpose of STOA, collective transactions and computation of transmission

deviation charges, there shall be separate slabs for injection and withdrawal rates.

2.8.1.c. Methodology for calculation of Reliability Support Charge Rate and billing of

Reliability Support Charges

(i) Reliability Support Charges shall be 10% of the Monthly Transmission Charges.

The Reliability Support Charge Rate, in `/MW/month shall be as under:

[10% of the Monthly Transmission Charges of ISTS]/ [Total Approved Withdrawal of

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the Withdrawal DICs and Approved Injection of the Generators having LTA to target

region]

Reliability Support Charge for Withdrawal DIC shall be obtained by multiplying the

above rate (in `/MW/month) by Approved Withdrawal. For Generator with Long term

Access to target region shall be obtained by multiplying these charges by Approved

Injection.

The above rate shall also apply for additional MTOA.

(ii) Over/under recovery shall be adjusted in the transmission charges of ISTS in the third

part of bill in a manner as provided in Regulation 11(6) of these Regulations.

(iii) These charges shall also be applicable to STOA/collective transactions. The offset

shall also be given in the manner as provided in Regulation 11 (9) of these

Regulations.]81

2.8.2 DETERMINATION OF LOCATIONAL CHARGES IN DEMAND ZONES

While multiple generation zones shall be considered in a state, for each state there shall be a

single demand zone. This is essentially because, the interface of the CTU network with the

State is usually at either 400 kV or 220 kV nodes which are generally owned by the state

transmission utilities. The transmission bills by the CTU are generally raised on the STU or

the SEBs where state utilities have not been unbundled. While the nodal charges for access

by demand customers will be made available to the State Utilties, the manner of application

within the state would be left to the state utilities. This may change when the states

implement a „Point of Connection‟ based transmission pricing mechanism.

81
Added vide Third Amendment Regulations, 2015 w.e.f. 01.05.2015.

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Transmission access charges for demand zones are computed in a manner similar to the

transmission access charges for generation zones.

2.8.3 DETERMINATION OF LOSSES IN GENERATION ZONES

The loss allocators, computed at the nodal level are indicative of the percentage of losses to be

allocated to each node. The total system losses shall be computed as per the existing

methodology.

The detailed procedure for determination of losses using the loss allocation factors shall be

prepared by the NLDC within 30 days of the notification of these Regulations.

2.8.4 DETERMINATION OF LOSSES IN DEMAND ZONES

The loss allocators, computed at the nodal level are indicative of the percentage of losses to be

allocated to each node. The total system losses shall be computed as per the existing

methodology. The detailed procedure for allocation of losses shall be prepared by NLDC

within 30 days of the notification of these regulations.

906