ABT-UI & Deviation Settlement Mechanism (DSM)

05/03/2023 ERPC, KOLKATA 1

CERC (Deviation Settlement Mechanism and related matters) Regulations,2014 dated

06.01.14

Effective from 17.02.2014

S.KEJRIWAL ( Executive Engineer, Commercial), ERPC , Kolkata Mob: 09831919509

E-mail : [email protected]


TARIFF REGIME-BRIEF OVERVIEW• Two part Tariff since 1992 (K.P.Rao Committee

Report)• Both Fixed Cost as well as Variable Cost were

charged to the beneficiaries in the proportion of actual energy drawn by them during a period

• Generating stations were paid incentive at a certain rate for any excess generation over and above the designated PLF


TARIFF REGIME-BRIEF OVERVIEW• Low freq during peak time• High freq during off-peak time• Rapid and wide changes in freq ( apprx 1 Hz in

5-10 minutes)• Frequent grid disturbance resulting in tripping

of generating stations, interruption of supply to large blocks of consumers and disintegration of regional grid


TARIFF REGIME-BRIEF OVERVIEW• Govt appoints M/s ECC,USA in 1994 to prepare and

submit a report• Report concludes faulty tariff regime• Perpetual conflict of commercial interest• Suggested implementation of ABT• Govt constitutes NTF/RTFs in 1995 to study the report• Govt pursued its efforts, held due consultations and

finally forwarded the ECC report alongwith NTF minutes and a note on ABT to CERC in May 1999


TARIFF REGIME-BRIEF OVERVIEW• The matter was heard in CERC from 26-28th of

July,1999• CERC issued ABT order dated 04.01.2000• Order stayed various High courts of the country

due to objections/apprehensions expressed by various SEBs/GENCOs

• Hon’ble Supreme court finally vacated the stay• ABT implemented in WR wef 01.07.2002 and

than in all other regions

ABT TARIFF STRUCTURE: THREE PART TARIFF:

1. FIXED CHARGE:• Generators assigned target availability• Total fixed cost payable to a generator over the year is linked

to the average annual availability. Hence the name Availability Based Tariff

• Charged to beneficiaries in the proportion of their share in the generating station

2. VARIABLE CHARGE:• Charged to beneficiaries to the extent of their drawal schedule

ABT TARIFF STRUCTURE: THREE PART TARIFF:3. UNSCHEDULED INTERCHANGE(UI) CHARGE:• Actual Generation – Scheduled Generation (For

Generators)• Total Actual Drawal – Total Scheduled Drawal (For

Beneficiaries)• Worked out for each 15 min time block • Based on average frequency of the relevant time

block

ABT TARIFF STRUCTURE: THREE PART TARIFF:3. UNSCHEDULED INTERCHANGE(UI) CHARGE:• Overdrawal/Underinjection under low freq

(Penalty)• Overinjection/Underdrawal under high freq (Nil

or low reward)• Overdrawal/Underinjection under high freq (Nil

or low Penalty)• Overinjection/Underdrawal under low freq

(Reward)

UI ACCOUNTING – PRELIMINARY PROCESS AND ROLE OF RLDCs:SCHEDULING:• Each day of 24 hours starting from 00.00 hours be divided into

96 time blocks of 15 minutes each• Each generating station is to make advance declaration of its

capacity for generation in terms of MWh delivery ex-bus for each time block of the next day

• Based on the above declaration, concerned RLDC shall communicate to the various beneficiaries their respective shares of the available capability

• After the beneficiaries give their requisition for power based on the generation schedules, the RLDC shall prepare the generation schedules and drawal schedules for each time block after taking into account technical limitations and transmission constraints

UI ACCOUNTING – PRELIMINARY PROCESS AND ROLE OF RLDCs:

METERING AND METERDATA PROCESSING:

• All Regional entities including beneficiaries/generators are responsible for downloading raw meterdata and sending it to RLDC

• RLDC to further process the data and transmit the processed data to RPC for accounting purpose

• RLDC to also send time block wise frequency for each day of the week along with time block wise schedule for each regional entity for each day of the week

• RLDC to also intimate any discrepancy with respect to addition/outage of any line in the network of any entity, outage of any generating unit, any erroneous metering, and any other information having commercial implication

UI ACCOUNTING –ROLE OF RPCs:

• Design program as per the relevant CERC Regulation incorporating various rate/volume capping and UI rate vector for accounting

• Every week download the processed meterdata along with schedule and frequency sent by RLDC

• Incorporate the changes/discrepancies in the network and metering with respect to the previous week

• Feed inputs(Actual, Schedule and frequency) to the program

UI ACCOUNTING –ROLE OF RPCs:

• Calculate Total Actual drawal/injection, Schedule drawal/injection and UI/Deviation charges including additional UI/Deviation charges for each regional entity for each day of the week

• Calculate Total Actual drawal/injection, Schedule drawal/injection and UI/Deviation charges including additional UI/Deviation charges for each regional entity for entire week

• Apportion any pool surplus/deficit among the beneficiaries• Issue the final weekly account and publish in the website• Revise the account as and when required

UI MECHANISM: 2003-2013

• Initially freq band fixed at 50.5 – 49 Hz • Gradually narrowed down to 50.2 – 49.7 Hz• max UI rate linked to the cost of generation from

diesel or liquid fuel based generating stations• Altered considering variation in prices of costly

fuel• ISGS capping of 105% wrt to DC in a time block

and 101% wrt to DC over a day• Additional UI Charge


Replacement of UI Regulations which was in effect since 17.09.12

Objective:• Discourage deviation from Schedule• Operate within the freq band• Ensure grid security • Operation of network elements within acceptable limits

Important Changes vis-à-vis UI regulation:• Buyer/Seller• Rate vector:


SL No RATE FOR DEVIATION CHARGE

1 f>=50.05Hz, RDC=0

2 50.05>f>=50.00, RDC increases by 35.6 p/u for each 0.01Hz step

3 50.00>f>=49.7, RDC increases by 20.84 p/u for each 0.01Hz step4 f<49.7,RDC=824.04p/u

50.250.15

50.1

50.0499999999999 50

49.9499999999999

49.8999999999999

49.849999999999849.8

49.7499999999999

49.6999999999999

49.6499999999998

49.5999999999998

49.5499999999997

49.49999999999960

100200300400500600700800900

Rate for Deviation Charge ( paise/unit )


178 paise/unit at 50 Hz

803.2 paise/unit at 49.7 Hz

Maximum Deviation Rate = 824.04 paise/unit


• BUYERs/SELLERs

1. Overinjection/Underdrawal:

• Charges for Deviation receivable for overinjection/underdrawal in a time block within the volume capping of 12% of Schedule or 150MW whichever is less in normal Deviation Charge depending on freq.

• For any overinjection/underdrawal beyond the volume capping limit in a time block, the charges receivable is zero.

• Additional Charges for Deviation for overinjection/underdrawal in any time block when f>=50.10Hz at 178 p/u


2. Overdrawal/Underinjection:A. Charges for Deviation payable for

overdrawal/underinjection in a time block in normal Deviation Charge depending on freq.

B. Additional charges for Deviation levied for overdrawal/underinjection beyond the volume capping limit as follows:

• Freq ---- 49.7 Hz and above & Sch >= 150 MWa. 12% of Sch in a time block < = 150 MW

Overdrawal/Underinjection

12-15% 15-20% Above 20%

Additional Charges for Deviation

20 % of Normal Deviation Charge

depending on average freq of that

block



block



block


b) 12% of Sch in a time block > 150 MW

• Freq ---- Below 49.7 Hz

Additional Charges levied = 824.04 p/uTotal Charges = 1648.08 p/u


150-200MW 200-250MW Above 250MW


20 % of Normal Deviation Charge depending on average freq of that block




Corrigendum dated 17.02.14Freq ---- 49.7 Hz and above & Sch < 150 MW


12-15% of 150 MW 15-20% of 150 MW Above 20% of 150 MW




block



block



block


DEVIATION

UNDERINJECTION / OVERDRAWAL

OVERINJECTION / UNDERDRAWAL

HIGH FREQ HIGH FREQLOW FREQ LOW FREQ

NIL OR LOW DC PAYABLE,

NIL OR LOW ADC PAYABLE

NIL OR LOW DC RECEIVABLE,NIL OR ADC

PAYABLE AT 178 P/U

HIGH DC PAYABLE,HIGH ADC PAYABLE

DC RECEIVABLE TILL MIN OF 12

% OF SCH OR 150 MW,

NO ADC PAYABLE

DC = DEVIATION CHARGEADC = ADDITIONAL CHARGE FOR DEVIATION


ILLUSTRATIONS:(All Energy figures in MWH)

Sch Act Dev Freq(in Hz)

Dev Rate ( Rs/MWH)

Dev Charge Receivable (+)/Payable(-)(in Rs.)

Quantum of Deviation for Addl Dev Charge

Additional Dev Charge Payable(in Rs.)

1 -204.34 -173.68 30.66 49.81 5739.6 24.52*5739.6 0 0

2 -204.37 -191.10 13.27 50.07 0 0 0 0

3 -167.45 -131.98 35.47 49.61 8240.40 20.05*8240.4 0 0

4 -224.45 -257.57 -33.12 50.07 0 0 0 0

5 -241.38 -238.82 2.56 50.11 0 0 2.56 -2.56*1780

6 -209.65 -278.11 -68.54 50.02 1068 -68.54*1068 43.38 -34239

7 -364.09 -434.52 -70.43 50.01 1424 -70.43*1424 32.93 -21972

8 -31.752 -56.137 -24.384 50.04 356 -24.384*356 19.88 -6356

9 -186.88 -220.23 -33.35 49.64

8240.40 -33.35*8240.4 33.35 -33.35*8240.4

Schedule = -204.34MWH Actual = -173.68MWH Deviation(Underdrawal) = -173.68-(-204.34) = 30.66MWH Freq = 49.81 Hz, Dev Rate = 5739.60 Rs/MWH Min ( 12% of Sch=24.52, 37.5) = 24.52MWH Deviation Charges Receivable = Rs. 24.52* 5739.6 Additional Deviation Charges Payable = 0

05/03/2023 22ERPC, KOLKATA

UTILITY DATE TIME BLOCKGRIDCO 01.05.14 00.00 HRS


Schedule = -241.38MWH Actual = -238.82MWH Deviation(Underdrawal) = -238.82-(-241.38) = 2.56MWH Freq = 50.11 Hz, Dev Rate = 0.00 Re/MWH Deviation Charges Receivable = Rs. 0* 2.56= 0 Additional Deviation Charges Payable = Rs. 2.56 * 1780 = Rs 4558

Schedule = -209.65MWH Actual = -278.11MWH Deviation = -278.11-(-209.65) = -68.54MWH Freq = 50.02 Hz, Dev Rate = 1068 Rs/MWH Min ( 12% of Sch=25.16, 37.5) = 25.16MWH Overdrawal allowed without levy of Addl Charge for Deviation = 25.16MWH Quantum of Overdrawal on which Addl Charges for Deviation to be levied = 68.54-25.16 = 43.38 MWH

05/03/2023 23ERPC, KOLKATA

12-1

5%

3% of Sch*20% of Dev Rate of that time block= 0.03*209.65*0.2*1068= Rs1343.43 15

-20%

5% of Sch*40% of Dev Rate of that time block= 0.05*209.65*0.4*1068= Rs4478.12

Abov

e 20

%

(43.38-8% of Sch)*100% of Dev Rate of that time block= 26.608*1*1068=Rs28417.34



Schedule = -364.09MWH Actual = -434.52MWH Deviation = -434.52-(-364.09) = -70.43MWH Freq = 50.01 Hz, Dev Rate = 1424 Rs/MWH Min ( 12% of Sch=43.69, 37.5) = 37.5MWH Overdrawal allowed without levy of Addl Charge for Deviation = 37.5MWH Quantum of Overdrawal on which Addl Charges for Deviation to be levied = 70.43-37.50 = 32.93 MWH

150-

200M

W

(200-150)/4*20% of Dev Rate of that time block= 12.5*0.2*1424=Rs 3560

200-

250M

W(250-200)/4*40% of Dev Rate of that time block= 12.5*0.4*1424=Rs 7120

Abov

e 25

0MW

(32.93-12.5-12.5)*100% of Dev Rate of that time block= 7.93*1*1424=Rs 11292.32

UTILITY DATE TIME BLOCKWBSETCL 10.03.14 21.00 HRS


Schedule = -31.752MWH Actual = -56.137MWH Deviation = -56.137-(-31.752) = -24.384MWH Freq = 50.04 Hz, Dev Rate = 356 Rs/MWHOverdrawal allowed without levy of Addl Charge for Deviation = 12% of 37.5= 4.5MWH Quantum of Overdrawal on which Addl Charges for Deviation to be levied = 24.38-4.5 = 19.88 MWH

12-1

5%

3% of 37.5*20% of Dev Rate of that time block= 1.125*0.2*356= Rs80.10 15

-20%

5% of 37.5*40% of Dev Rate of that time block= 1.875*0.4*356= Rs267

Abov

e 20

%

(19.88-8% of 37.5)*100% of Dev Rate of that time block= 16.88*1*356=Rs6009.28



50.250.15

50.1

50.0499999999999 50

49.9499999999999

49.8999999999999

49.849999999999849.8

49.7499999999999

49.6999999999999

49.6499999999998

49.5999999999998

49.54999999999970

50

100

150

200

250

300

350



178 paise/unit at 50 Hz

Maximum Deviation Rate = 303.04 paise/unit

• Thermal Stations regulated by CERC and using coal under APM as fuel:


• Thermal Stations regulated by CERC and using coal under APM as fuel:

1. 105% time block capping and 101% day capping w.r.t DC of ISGS has been done away with

2. Overinjection:

• Charges for Deviation receivable for overinjection in a time block within the volume capping of 12% of Schedule or 150MW whichever is less in normal Deviation Charge subject to a capping of 303.04p/u depending on freq.

• For any overinjection beyond the volume capping limit in a time block, the charges receivable is zero.

• Additional Charges for Deviation for overinjection in any time block when f>=50.10Hz at 178 p/u


3. Underinjection:A. Charges for Deviation payable for underinjection in

a time block in normal Deviation Charge subject to a capping of 303.04p/u depending on freq.

B. Additional charges for Deviation levied for underinjection beyond the volume capping limit as follows:

• Freq ---- 49.7 Hz and above & Sch >= 150 MWa. 12% of Sch in a time block < = 150 MW

Underinjection 12-15% 15-20% Above 20%Additional Charges for Deviation

20 % of MIN(303.04p/u , Normal Deviation Charge)




b) 12% of Sch in a time block > 150 MW

This is a new provision added to this regulation.

• Freq ---- Below 49.7 Hz

Additonal Charges levied = 303.04 p/u Total Charges = 606.08 p/u

Underinjection 150-200MW 200-250MW Above 250MWAdditional Charges for Deviation





ILLUSTRATION:

1) Overinjection

Sch Act Dev Freq Dev Rate Dev RateApplic-able

Min (12% of Col2,150)

Dev Charge Receivable

Additional Dev Charge Payable

1 1450 1480 30 49.9 407.24 303.04 150 30*303.04 0

2 1450 1680 230 50 178 178 150 150*178 0

3 1200 1380 180 49.96 261.36 261.36 144 144*261.36 0

4 1300 1350 50 50.12 0 178 0 50*178


Sch Act Dev Freq Dev Rate Dev RateApplic-able

Min (12% of Col2,150)

Dev Charge Payable

Additional Dev Charge Payable

1 1450 1420 -30 49.9 407.24 303.04 150 30*303.04 0

2 1450 1280 -170 50 178 178 150 170*178 20*.2*178

3 1450 1240 -210 49.96 261.36 261.36 150 210*261.36 50*0.2*261.36+10*0.4*261.36

4 1450 1190 -260 49.8 594.8 303.04 150 260*303.04 50*0.2*303.04+50*0.4*303.04+10*303.04

5 1180 1150 -30 49.75 678.16 303.04 141.6 30*303.04 0

6 1180 1000 -180 49.98 219.68 219.68 141.6 180*219.68 35.4*0.2*219.68+3*0.4*219.68

7 1180 940 -240 49.88 428.08 303.04 141.6 240*303.04 35.4*0.2*303.04+59*0.4*303.04+4*303.04

8 1180 1075 -105 49.70 803.2 303.04 141.6 105*303.04 0

9 1180 1075 -105 49.69 803.2 303.04 141.6 105*303.04 105*303.04

UNDERINJECTION


In a time block: Sch injection = 1450MW Act injection= 1190MW Deviation =1190-1450 = -260MW Freq = 49.8 Hz, Dev Rate = 594.80 paise/unit Dev Rate applicable = MIN( Normal Dev Rate, 303.04)=303.04 paise/unit Min ( 12% of Sch=174MW, 150MW) = 150MW Total underinj allowed without levy of Addl Charge for Deviation = 150MWQuantum of Underinjection on which Addl Charges for Deviation to be levied = 260-150 = 110 MW

150-

200M

W

(200-150)*20% of MIN(Normal Dev Rate of that time block,303.04)= 50*0.2*303.04paisa/unit

200-

250M

W

(250-200)*40% of MIN(Normal Dev Rate of that time block,303.04)= 50*0.4*303.04paisa/unit

Abov

e 25

0MW

(110-50-50)*100% of MIN(Normal Dev Rate of that time block,303.04)= 10*1*303.04paisa/unit


In a time block: Sch injection = 1180MW Act injection= 940MW Deviation = 940-1180 = -240MW Freq = 49.88 Hz, Dev Rate = 428.08 paisa/unit Dev Rate applicable = MIN( Normal Dev Rate, 303.04)=303.04 paise/unit Min ( 12% of Sch=141.6MW, 150MW) = 141.6MW Total underinj allowed without levy of Addl Charge for Deviation = 141.6MWQuantum of Underinjection on which Addl Charges for Deviation to be levied = 240-141.6 = 98.4 MW

12-1

5%

3% of Sch*20% MIN(Normal Dev Rate of that time block,303.04)= 35.4*0.2*303.04 paisa/unit 15

-20%

5% of Sch*40% MIN(Normal Dev Rate of that time block,303.04)= 59*0.4*303.04 paisa/unit

Abov

e 20

%

(98.4-8%of Sch)*100% MIN(Normal Dev Rate of that time block,303.04)= 4*1*303.04 paisa/unit


• Infirm power:

1. Injection:

• Period of 6 months allowed • Domestic coal/lignite/hydro: 178p/u against 165 p/u• Imported coal: 303p/u against 330p/u• Exemption from volume limit

2. Drawal:

• Exemption from volume limit for f>=49.7Hz• No levy of Additional charges for deviation at f<49.7Hz. (As

per present UI regulation Addl. UI Charges applicable)


Accounting of Charges for Deviation:

• RLDCs to furnish data by every Thursday • RPCs to prepare and issue statement of Deviation

including Additional Charges for Deviation by every Tuesday for 7 day period ending on penultimate Sunday.

• All payments including interest , if any, to be credited to “Regional Deviation Pool Account Fund”

• Fund to be operated and maintained by RLDCs


Other Important Clauses:• Any Additional Charge for Deviation collected from a

regional entity shall be retained in the “Regional Deviation Pool Account Fund” of the concerned region where the regional entity is located

• In the event of sustained deviation from schedule in one direction (positive or negative) by any regional entity, such regional entity (buyer or seller) shall have to make sign of their deviation from schedule changed, at least once, after every 12 time blocks. To illustrate, if a regional entity has positive deviation from schedule from 07.30 hrs to 10.30 hrs, sign of its deviation from schedule shall be changed in the 13th time block i.e. 10.30 to 10.45 hrs from positive to negative or negative to positive as the case may be.


Other Important Clauses: (contd…….)• RLDCs shall, on monthly basis, prepare and publish on its

website the records of the Deviation Accounts, specifying the quantum of over-drawl/ under-injection and corresponding amount of Charges for Deviation payable/receivable for each buyer and seller for all the time-blocks when grid frequency was "49.90Hz and above" and "below 49.90" Hz separately.”

• Any surplus amount in the Deviation Pool Account Fund on the last day of the month shall be transferred to PSDF in first week of the next month

• On commencement of these regulations:a) CERC (UI & related matters) regulation shall stand repealedb) Regional UI Pool Account Fund shall continue to operate till

the UI Accounts settlement is completed


Schedule of Payments:• Payment to be made within 10 days of issue of statement by RPC• For delay of more than 2 days i.e beyond 12 days of issue of statement by RPC, simple

interest @ 0.04% to be levied for each day of delay• Payments to receivable entities to be made within 2 working days of receipt of

payments in the fund• In the event of delay of payment by Payable entities, the receivable entities shall be

paid from the balance in the fund. If sufficient fund not there, payment to be made on pro rata basis

• Utilities defaulting at any time in previous FY shall open an LC equal to 110% of its average payable weekly liability in favour of the concerned RLDC within a fortnight of date these regulations come into force

• Utilities defaulting at any time in current FY shall open an LC equal to 110% of its weekly outstanding liability in favour of the concerned RLDC within a fortnight from the due date of payment

• LC to be increased to 110% of the payable weekly liability for Deviation in any week during the year, if it exceeds the previous LC amount by more than 50%

• For payments not received within 12 days, RLDC entitled to encash the LC to the extent of default which has be recouped within 3 days


Relevant Clauses from IEGC , 2nd Amendment Regulations effective from 17.02.2014• Clause 3(7)(g):”RLDCs shall devise standard instantaneous message formats in order to

give directions in case of contingencies and/or threat to the system security to reduce deviation from schedule by the bulk consumer, SLDC/StateUtility/ISGS/Regional Entity/Injecting Utility at different overdrawal/underdrawal/over-injection/underinjection conditions depending upon the severity. The concerned SLDC/other regional entity shall ensure immediate compliance with these directions of RLDC and send a compliance report to the concerned RLDC “

• Clause 4(1): “……..The regional entities shall regulate their generation and/or consumers’ load so as to maintain their actual drawl from the regional grid close to the above schedule. Maximum inadvertent deviation allowed during a time block shall not exceed the limits specified in the Deviation Settlement Mechanism Regulations. Such deviations should not cause system parameters to deteriorate beyond permissible limits and should not lead to unacceptable line loadings. Inadvertent deviations, if any, from net drawl schedule shall be priced through the Deviation Settlement mechanism as specified by the Central Commission from time to time. Every regional entity shall ensure reversal of sign of deviation from schedule at least once after every twelve time blocks”


Relevant Clauses from IEGC , 2nd Amendment Regulations effective from 17.02.2014 (contd…)• Clause 4(2)(7): ”The SLDC, SEB / distribution licensee shall always restrict the net drawl of the

state from the grid within the drawl schedule keeping the deviations from the schedule within the limits specified in the Deviation Settlement Mechanism Regulations. The concerned SEB/distribution licensee/User, SLDC shall ensure that their automatic demand management scheme mentioned in clause 5.4.2 acts to ensure that there is no over-drawl. If the automatic demand management scheme has not yet been commissioned, then action shall be taken as per manual demand management scheme to restrict the net drawal from grid to within schedules and all actions for early commissioning of Automatic Demand Management Scheme (ADMS) shall be initiated “

• Clause 4(3)(10): The ISGS is normally expected to generate power according to the daily schedules advised to them barring any inadvertent deviations. Maximum deviation allowed during a time block shall not exceed the limits specified in the Deviation Settlement Mechanism Regulations. Such deviations should not cause system parameters to deteriorate beyond permissible limits and should not lead to unacceptable line loadings. Inadvertent deviations, if any, from the ex-power plant generation schedules shall be appropriately priced in accordance with Deviation Settlement Mechanism Regulations. In addition, deviations from schedules causing congestion, shall also be priced in accordance with the Central Electricity Regulatory Commission (Measure to relieve congestion in real time operation) Regulations, 2009”


Relevant Clauses from IEGC , 2nd Amendment Regulations effective from 17.02.2014 (contd…)• Clause 4(5)(12): …….. the RLDC may direct the SLDCs/ISGS/

other regional entities to increase/decrease their drawal/generation in case of contingencies e.g. overloading of lines/transformers, abnormal voltages,threat to system security. Such directions shall immediately be acted upon. Incase the situation does not call for very urgent action, and RLDC has some time for analysis, it shall be checked whether the situation has arisen due to deviations from schedules…….

• Clause 4(7)(24): "Hydro generating stations are expected to respond to grid frequency changes and inflow fluctuations. Maximum deviation allowed during a time block shall be as per the CERC Deviation Settlement Mechanism Regulations."


THANK YOU

ABT-UI & Deviation Settlement Mechanism (DSM)

Presentations & Public Speaking

Transcript of ABT-UI & Deviation Settlement Mechanism (DSM)