Deviation Settlement

8/12/2019 Deviation Settlement

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CERC (Deviation Settlement

Mechanism and related matters),

Effective from 17.02.2014

2/10/2014 1ERPC, KOLKATA


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Replacement of existing UI Regulations which is

effective since 17.09.12

Objective:

Discourage deviation from Schedule

Operate within the freq band

Ensure grid security

Important Changes vis--vis Existing UI regulation:

Buyer/Seller Rate vector:



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SL No EXISTING UI RATE

1 f>=50.20Hz, RUI=0

2 50.20>f>=50.00, RUI increases by 16.5 p/u for each 0.02Hz step

3 50.00>f>=49.8,RUI increases by 28.50 p/u for each 0.02Hz step4 49.8>f>=49.50, RUI increases by 28.12 p/u for each 0.02Hz step

5 f


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SL No NEW 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 step

4 f


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BUYERs/SELLERs

1. Overinjection/Underdrawal:

Charges for Deviation receivable foroverinjection/underdrawal in a time block withinthe volume capping of 12% of Schedule or 150MWwhichever is less in normal Deviation Chargedepending on freq.

For any overinjection/underdrawal beyond thevolume capping limit in a time block, the charges

receivable is zero. Additional Charges for Deviation for

overinjection/underdrawal in any time block whenf>=50.10Hz at 178 p/u



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2. Overdrawal/Underinjection:

A. Charges for Deviation payable for

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

B. Additional charges for Deviation levied for

overdrawal/underinjection beyond the volume capping

limit as follows:---- .

a. 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

40 % of Normal

Deviation Charge

depending on


block

100 % of Normal

Deviation Charge

depending on


block



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

Overdrawal/

Underinjection

150-200MW 200-250MW Above 250MW

Additional Charges

for Deviation

20 % of Normal

Deviation Charge

depending on

average freq of

that block

40 % of Normal

Deviation Charge

depending on

average freq of

that block

100 % of Normal

Deviation Charge

depending on


block

This is a new provision added to this regulation.

Freq ---- Below 49.7 Hz

Additonal Charges levied = 2*824.04 p/u

= 1648.08 p/u



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ILLUSTRATION:

Buyer/Seller : Underdrawal/Overinjection:

Sch Act Dev Freq Dev Rate Min

(12% of

Col2,15

0)

Dev Charge

Receivable

Quantum of

Deviation for

Addl Dev

Charge

Additional

Dev

Charge

Payable

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

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

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

4 1300 1350 50 50.12 0 150 0 50 50*178

5 -120 -100 20 49.9 407.24 14.4 14.4*407.24 0 0

6 -1300 -1210 90 50 178 150 90*178 0 0

7 -1300 -1140 160 49.96 261.36 150 150*261.36 0 0

8 -1150 -1010 140 49.84 511.44 138 138*511.44 0 0

9 -300 -240 60 50.18 0 36 0 60 60*1782/10/2014 8ERPC, KOLKATA


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Sch Act Dev Freq Dev Rate Min

(12%of

Col2,

150)

Dev Charge

Payable

Quantum of

Deviation forAddl Dev

Charge

Additional Dev

Charge Payable

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

2 1450 1190 -260 49.8 594.8 150 260*594.8 110 50*0.2*594.8+50*0.4*594.8+10*594.8

Buyer/Seller: Overdrawal/Underinjection:

3 1180 940 -240 49.75 678.16 141.6 240*678.16 98.4 35.4*0.2*678.16+59*

0.4*678.16+4*678.16

4 1180 1150 -30 49.68 824.04 141.6 30*824.04 30 30*824.04

5 -400 -435 -35 50.01 142.40 48 35*142.4 0 0

6 -400 -485 -85 49.86 469.76 48 85*469.76 37 12*0.2*469.76+20*0.

4*469.76+5*469.76

7 -1400 -1665 -265 49.91 365.56 150 265*365.56 115 50*0.2*365.56+50+0.

4*365.56+15+365.56

8 -250 -282 -32 49.61 824.04 30 32*824.04 32 32*824.04



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In a time block: Sch injection = 1450MW Act injection= 1190MW

Deviation =1190-1450 = -260MW

Freq = 49.8 Hz, Dev Rate = 594.80 paisa/unit

Min ( 12% of Sch=174MW, 150MW) = 150MW

Total underinj allowed without levy of Addl Charge for Deviation = 150MW

Quantum of Underinjection on which Addl Charges for Deviation to be

levied = 260-150 = 110 MW

150-200MW

(200-150)*20% ofDev Rate of thattime block=50*0.2*594.8

paisa/unit 200-250MW

(250-200)*40% ofDev Rate of thattime block=50*0.4*594.8

paisa/unitAbo

ve250MW(110-50-

50)*100% ofDev Rate ofthat time

block=10*1*594.8paisa/unit



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In a time block: Sch Drawal = -400MW Act Drawal= -485MW

Deviation = -485-(-400)= -85MW


Min ( 12% of Sch=48MW, 150MW) = 48MW

Total overdrawal allowed without levy of Addl Charge for Deviation = 48MW

Quantum of Overdrawal on which Addl Charges for Deviation to be levied =

85-48 = 37 MW

12

-15%

3% of Sch*20%of Dev Rate ofthat time block=

12*0.2*469.76paisa/unit 15

-20%

5% of Sch*40%of Dev Rate ofthat time block=

20*0.4*469.76paisa/unit A

bove20%(37-8% of

Sch)*100% ofDev Rate of that

time block=5*1*469.76paisa/unit



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300

350

400

450

Existing UI Rate (paise/unit)

Maximum UI Rate

= 421.5 p/u

Thermal Stations regulated by CERC and using coal

under APM as fuel):

0

50

100

150

200

250

50.3

50.26

50.22

50.18

50.14

50.1

50.06

50.02

49.98

49.94

49.9

49.86

49.82

49.78

49.74

49.7

49.66

49.62

49.58

49.54

49.5

Existing UI Rate

(paise/unit)165 p/u at 50Hz



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250

300

350

Rate for Deviation Charge ( paise/unit )

Maximum Deviation Rate

= 303.04 paise/unit

Thermal Stations regulated by CERC and using coal

under APM as fuel:

0

50

100

150

200

50.2

50.15

50.1

50.05

50

49.95

49.9

49.85

49.8

49.75

49.7

49.65

49.6

49.55

Rate for Deviation

Charge ( paise/unit )

178 paise/unit at 50 Hz



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3. Underinjection:

A. Charges for Deviation payable for underinjection

in a time block in normal Deviation Chargesubject to a capping of 303.04p/u depending onfreq.

B. Additional charges for Deviation levied for

underinjection beyond the volume capping limitas follows:

Freq ---- 49.7 Hz and above

a. 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)

40 % of

MIN(303.04p/u ,

Normal Deviation

Charge)

100 % of

MIN(303.04p/u ,

Normal Deviation

Charge)



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

Underinjection 150-200MW 200-250MW Above 250MW

Additional Charges

for Deviation

20 % of

MIN(303.04p/u ,

Normal Deviation

Charge)

40 % of

MIN(303.04p/u ,

Normal Deviation

Charge)

100 % of

MIN(303.04p/u ,

Normal Deviation

Charge)

This is a new provision added to this regulation.

Freq ---- Below 49.7 Hz

Additonal Charges levied = 2*303.04 p/u

= 606.08 p/u



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ILLUSTRATION:

1) Overinjection

Sch Act Dev Freq Dev Rate Dev

Rate

Applic

-able

Min (12% of

Col2,150)

Dev Charge

Receivable

Additio

nal 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



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Sch Act Dev Freq Dev Rate Dev

RateApplic-

able

Min

(12% ofCol2,15

0)

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

* * * *

UNDERINJECTION

- . . . . . . .

*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



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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 = 150MW


levied = 260-150 = 110 MW

150-200MW

(200-150)*20% ofMIN(Normal DevRate of that time

block,303.04)=50*0.2*303.04paisa/unit 2

00-250MW

(250-200)*40% ofMIN(Normal DevRate of that time

block,303.04)=50*0.4*303.04paisa/unit

Above250MW(110-50-

50)*100% ofMIN(Normal

Dev Rate ofthat timeblock,303.04)=10*1*303.04paisa/unit



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Deviation = 940-1180 = -240MW


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 = 141.6MW


levied = 240-141.6 = 98.4 MW

12

-15%

3% of Sch*20%MIN(Normal DevRate of that timeblock,303.04)=

35.4*0.2*303.04paisa/unit

15

-20%

5% of Sch*40%MIN(Normal DevRate of that timeblock,303.04)=

59*0.4*303.04paisa/unit A

bove20%(98.4-8%of

Sch)*100%MIN(Normal DevRate of that time

block,303.04)=4*1*303.04paisa/unit



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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


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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 b ever Tuesda for 7 da eriodending on penultimate Sunday.

All payments including interest , if any, to becredited to Regional Deviation Pool AccountFund

Fund to be operated and maintained by RLDCs



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Other Important Clauses:

Any Additional Charge for Deviation collected from aregional entity shall be retained in the RegionalDeviation Pool Account Fund of the concerned regionwhere the regional entity is located

In the event of sustained deviation from schedule in

one direction (positive or negative) by any regional,

to make sign of their deviation from schedule changed,at least once, after every 12 time blocks. To illustrate, ifa regional entity has positive deviation from schedule

from 07.30 hrs to 10.30 hrs, sign of its deviation fromschedule shall be changed in the 13th time block i.e.10.30 to 10.45 hrs from positive to negative or negativeto positive as the case may be.



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Other Important Clauses: (contd.)

RLDCs shall, on monthly basis, prepare and publish on

its website the records of the DeviationAccounts, specifying the quantum of over-drawl/under-injection and corresponding amount of Chargesfor Deviation payable/receivable for each buyer andseller for all the time-blocks when grid frequency was

"49.90Hz and above" and "below 49.90" Hz separately. ny surp us amoun n e ev a on oo ccoun un

on the last day of the month shall be transferred toPSDF in first week of the next month

On commencement of these regulations:

a) CERC (UI & related matters) regulation shall standrepealed

b) Regional UI Pool Account Fund shall continue tooperate till the UI Accounts settlement is completed



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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 byRPC, 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 entitiesshall be paid from the balance in the fund. If sufficient fund not

there, payment to be made on pro rata basis Utilities defaultin at an time in revious FY shall o en an LC e ual to

110% of its average payable weekly liability in favour of the concernedRLDC 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 afortnight from the due date of payment

LC to be increased to 110% of the payable weekly liability for Deviation inany week during the year, if it exceeds the previous LC amount by morethan 50%

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



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Relevant Clauses from IEGC , 2nd Amendment

Regulations effective from 17.02.2014

Clause 3(7)(g):RLDCs shall devise standard instantaneous message formatsin order to give directions in case of contingencies and/or threat to thesystem security to reduce deviation from schedule by the bulkconsumer, SLDC/StateUtility/ISGS/Regional Entity/Injeecting Utility atdifferent overdrawal/underdrawal/over-injection/underinjection conditionsdepending upon the severity. The concerned SLDC/other regional entityshall ensure immediate compliance with these directions of RLDC and senda compliance report to the concerned RLDC

Clause 4(1): ..The regional entities shall regulate their generationand/or consumers load so as to maintain their actual drawl from theregional grid close to the above schedule. Maximum inadvertent deviationallowed during a time block shall not exceed the limits specified in the

Deviation Settlement Mechanism Regulations. Such deviations should notcause system parameters to deteriorate beyond permissible limits andshould not lead to unacceptable line loadings. Inadvertent deviations, ifany, from net drawl schedule shall be priced through the DeviationSettlement mechanism as specified by the Central Commission from time totime. Every regional entity shall ensure reversal of sign of deviation fromschedule at least once after every twelve time blocks



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Regulations effective from 17.02.2014 (contd)

Clause 4(2)(7): The SLDC, SEB / distribution licensee shall always restrict the netdrawl of the state from the grid within the drawl schedule keeping the deviationsfrom the schedule within the limits specified in the Deviation SettlementMechanism Regulations. The concerned SEB/distribution licensee/User, SLDC shallensure that their automatic demand management scheme mentioned in clause5.4.2 acts to ensure that there is no over-drawl. If the automatic demandmanagement scheme has not yet been commissioned, then action shall be taken as

per manual demand management scheme to restrict the net drawal from grid towithin schedules and all actions for early commissioning of Automatic Demandanagemen c eme s a e n a e

Clause 4(3)(10): The ISGS is normally expected to generate power according to thedaily schedules advised to them barring any inadvertent deviations. Maximumdeviation allowed during a time block shall not exceed the limits specified in theDeviation Settlement Mechanism Regulations. Such deviations should not cause

system parameters to deteriorate beyond permissible limits and should not lead tounacceptable line loadings. Inadvertent deviations, if any, from the ex-power plantgeneration schedules shall be appropriately priced in accordance with DeviationSettlement Mechanism Regulations. In addition, deviations from schedules causingcongestion, shall also be priced in accordance with the Central Electricity RegulatoryCommission (Measure to relieve congestion in real time operation)Regulations, 2009



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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.,

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."



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Deviation Settlement

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