Energy Accountingand

Need for Special Energy Metersunder ABT Regime

Energy Account

• The energy accounting closely monitors the energy flow within and beyond the organisation, and also to help identify areas where system efficiencies can be improved.

• It provides reports on the energy losses at each level of the transmission and distribution network, and within specific geographical regions.

• It also helps identify long- and short-term strategic management trends.

• To be FAIR and EQUITABLE• To RECOVER DUES at the EARLIEST (Billing Cycle)• TRANSPERANCY• Dispute Resolution• Reconciliation

Capacity charge:

Capacity charge is based on Annual Fixed Charge and will be related to availability of generating station. Availability means the readiness of the generating station to deliver ex-bus output expressed as a percentage of its rated ex-bus output capability.

Energy charge:

Energy charge is related to the scheduled ex-bus energy to be sent out from the generating station and will be worked out on the basis of paise per KWh.

AVAILABILITY TARIFF(ABT)(a) CAPACITY CHARGE(b) ENERGY CHARGE(c) ADJUSTMENT FOR DEVIATIONS

(UI CHARGE)

(a) = a function of Ex-bus MW availability of power plant for the day declared before the day starts x SEB’s % share

.(b) = MWh for the day as per ex=bus drawl schedule for the SEB

finalized before the day starts x Energy charge rate

(c) =Σ(Actual energy interchange in a 15 min time block – scheduled energy interchange for the time block) x UI rate for the time block.

TOTAL PAYMENT FOR THE DAY =(a) + (b)± ( c)

SETTLEMENT SYSTEMFor the day: 0000 hrs. to 2400 hrs.

Central Generating Stations 1 2 3

Ex-Bus Capability x1 x2 x3(Forecast) ____ ___ ___

SEB-A’s share a1 a2 a3SEB-B’s share b1 b2 b3SEB-C’s share c1 c2 c3

For a particular 15 minute time block

SEB-A’s requisition a’1 a’2 a’3SEB-B’s requisition b’1 b’2 b’3SEB-C’s requisition c’1 c’2 c’3

___ ___ ___CGS’s schedule x1’ x2’ x3’

MW

SRLDC/Comml/IEGC/37

SETTLEMENT SYSTEM

Total capacity charge payable to CGS-1 for the day= x1 * capacity charge rate of CGS-1

Total Energy charge payable to CGS-1 for the day

= x1’ * Energy charge rate of CGS-1 4

Total capacity charge payable by SEB-A for the day

= a1 * capacity charge rate of CGS-1

+ a2 * -do- CGS-2

+ a3 * -do- CGS-3Total Energy charge payable by SEB-A for the day

= (a1’) * Energy charge rate of CGS-1 ( 4 )

+ (a2’) * -do- CGS-2 ( 4 )

+ (a3’) * -do- CGS-3 ( 4 )

All capacity charge and Energy charge payments to be made by SEBs directly to CGS.

SRLDC/Comml/IEGC/38

SETTLEMENT SYSTEM

Actual (metered) injection of CGS-1 in the time block = X1 MWh.

Excess injection = (X1 – x1’ ) MWh.

4

Amount payable to CGS-1 for this =(X1-x1’) * pool price for the block.

4

SEB-A’s scheduled drawl for time block = a1’+a2’+a3’ = a’ MW (ex-CGS Bus)

SEB-A’s NET drawal schedule = (a’ – Notional Transm. Loss) MW

= (a’ – Notional Transm. Loss) = A’ MWH

4

Actual (metered) net drawal of SEB-A during time block = A MWH

Excess drawal by SEB-A = (A-A’) MWh.

Amount payable by SEB-A for this = (A-A’) * pool price for the block.

All above payments for deviations from schedules to be routed through a pool A/C operated by RLDC

SRLDC/Comml/IEGC/39

AVAILABILITY

• Availability in relation to a generating station for any period means the average of the DCs for all the days during that period expressed as a percentage of the installed capacity of generating station minus normative auxiliary consumption in MW and shall be computed as per the following formula:

Present Definition Capacity charges

% Availability = i=1

N

DCi/ {NxICx(100-Auxn) }%10000

Where DCi = Average Declared Capacity for i th day of the period in MW N = Total no. of days during the period Auxn = Normative Auxiliary Consumption as % of gross Gen.

IC= installed capacity in MW

% Availability forms the basis for calculations

i=1

N

SGi/ {NxICx(100-Auxn) }%10000PLF =

Recovery of Annual fixed charges 100% recovery if % Availability >=Target Availability

- Pro-rata reduction if %Avb<T.Avb.

- Target Availability For Fixed charges recovery - Target PLF for incentive

-Both to be Notified by CERC-Financial Year forms the basis for calculations

ISGS Target Availabilty Target PLF

RSTPS 80% 80%

NLC 75% 75%

Monthly Capacity charges receivable by an ISGS:1 st Month = (1xACC1)122 nd Month = (2xACC2-1ACC1)12….….12 th month = (12xACC12-11ACC11)12where ACC1,ACC2…….ACC12 = Annual capacity charges corresponding to the cum. Availability up to the corresponding month.

Monthly Capacity charges payable by a beneficiary :1 st Month = (1xACC1xWB1)122 nd Month = (2xACC2xWB2-1ACC1xWB1)12….….12 th month = (12xACC12xWB12-11xACC11xWB11)12where WB1,WB2…..WB12 = Weighted average % share up to the corresponding month.

Name Of ISGS

Aux.

Consumption

Variable

Charges (Ps)

RSTPS 7.93% 98

NLC II/1 10.00% 75

NLC II/2 10.00% 100

NLC TPS 1 (EXP)

9.50% 131

TALCHER-

STAGE II

7.5% 74

Energy charges

The Energy Charges Payable by beneficiary to the ISGS =

Variable Charge of ISGS X

Requisition of beneficiary from The ISGS

The Energy Charges Receivable by ISGS from beneficiaries =

Variable Charge of ISGS X

Despatch schedule of ISGS

• Flat rate of 25ps/u

• For ex-bus Schedule Energy in Excess of ex-bus energy corresponding to Target PLF

Incentive as per existing norms

Settlement Systems* On weekly basis : For seven day period ending on penultimate Sunday

•RLDC to furnish Scheduling & Metering data to REB• Sectt. by Thursday noon

•REB Sectt. to issue Weekly UI a/c by Tuesday

•Pool a/c operated by RLDC•Settlement for UI on weekly basis•All accounts open for 20 days

SRLDC/Comml/IEGC/34

Settlement System contd..

• On monthly basis :• REB to issue REA specifying % Avb, %

Net Entitlement, % Energy charges, Wt. Avg. Ent. for Tr. Ch. etc.

• Capacity and Energy Charges, Incentive etc.

• –billed directly by ISGS based on REA issued by REB

WEEKLY ENERGY ACCOUNTING:

WEEKLY CYCLE : 00 HRS OF EACH MONDAY TO 24 HRS; OF THE THE FOLLOWING SUNDAY

ACTIVITIES MONDAY MORNING : SEM DATA DOWNLOADED TO DCD

: DCD DATA LOADED TO A LOCAL PC: DATA SENT TO RLDC via E-MAIL

(LATEST TUESDAY MORNING )THURSDAY NOON : RLDC CONVEYS PROCESSED DATA TO

REBTues day : WEEKLY UI a/c & Reactive charges

issued BY REBBILLING

Cap. Charge : BILLED MONTHLY based on DAILY DC BY ISGS

ENERGY CHARGE : BILLED MONTHLY based on DAILY DRAWL SCHEDULES ISSUED BY RLDC

UI a/c Paid/Disbursed as per UI a/c issued by REB

REACTIVE a/c

Variations in actual generation/drawal and scheduled generation /drawal are accounted through UI. This is a frequency linked charge which is worked out for each 15 minute time block.

Charges for all UI transaction, based on average frequency have following rate of paise per KWh from 01.01.03 up to 31.03.04.

UI rate (Paise per KWh)

Average Frequency of time block50.5 Hz. and above 0.0Below 50.5 Hz. and upto 50.48 Hz. 5.6Below 49.04 Hz. and upto 49.02 Hz. 414.4Below 49.02 Hz. 420.0Between 50.5 Hz. and 49.02 Hz. Linear in 0.02 Hz. step

Unscheduled Interchanges (UI)

• Present UI rate UI rate (Paise per KWh)

Average Frequency of time block (Hz,)Below Not below ----- 50.50 0.050.50 50.48 6.050.48 50.46 12.0----- ----- ----- ----- ----- ----- 49.84 49.82 204.049.82 49.80 210.049.80 49.78 219.049.78 49.76 228.0----- ----- ----- 49.52 49.50 345.049.50 49.48 329.0 ----- ----- ----- 49.04 49.02 729.049.02 ----- 745

(Each 0.02 Hz. Step is equivalent to 6.0 paise/kWh in the 50.5-49.8 Hz. Frequency range and to 9.0 paise/kWh in the 49.8-49.5 Hz. Frequency range and to 16.0 paise/kWh in the 49.5-49.0 Hz. Frequency range).

Energy transactions of UI from/to Pool

Over Gen. By ISGS-1

Under drawl by SEB-A

UI import from IR-1

Under gen. By ISGS-2

No one to one correspondence

System frequency UI

RateRegional Pool

Over drawl by SEB-BUI Export to IR-2

Operation of Pool

Separate Pool a/cs operated by RLDCs on behalf of REBs for UI, IRE and Reactive charges

Regional Pool

Payable by ISGS-2

Payable by SEB-BPayable by IR-2at its UI rate

Receivable by ISGS-1 (up to DC) Receivable by SEB-A Receivable by IR-1

at its UI rateNo one to one correspondence

No cross adjustments allowed between the constituents

Where do SEMs come into picture?

• Only measuring Deviations from Schedulei.e. UI

• To measure 15 min block-wise Energy and Frequency

Issues concerned :-Specifications-Location criterion-Main/Check/Standby philosophy

ISTS

ISGS -II

SEB-B drawalMain = (T+U+X)

Standby = (V+W+Y)

SEB-A drawalMain = (G+H+N+O+Y)Standby = (L+M+Q+R+X)

Metering Philosophy under ABT regime

Other than NTPC Station

ISGS-I injectionMain = (F+G+H+J+K)Check=(F'+L+M+J'+K')Standby = (A+B+C+D+E)

NTPC Station

SEB-B

ISGS-II injectionMain = (M1+M2)Check=(C1+C2)Standby = (S1+S2)

ISGS -I

Aux. Aux.

ISTS

ISTS

SEB-A

SEB-A

A B D EC

FF'

G HJJ'

KK'

L M

SEB-A

ST U

VW

X

Y

SEB-B

N O P

Q R

C1 C2

M1 M2

S1 S2

Aux.

Main Meter

Standby Meter

Check Meter

Points for Energy AccountingInjection by NTPC Generating Stations :

Main &check meters on Outgoing feeders Standby meters on HV side of GT/TT

Injection by other Generating Stations :

Main &check meters on HV side of GT/TT Standby meters on Outgoing feeders

Drawl by SEBs

Main -HV side of ICTs at GS and CTU S/S, Receiving end of Lines directly connected to ISGS

Respective ends of Lines connected to other SEBs Standby – LV/ Tertiary side of ICTs

Other end of lines connected to other SEBs

Special Energy Meter FeaturesSpecial Energy Meter Features

• STATIC TYPE

• COMPOSITE METER

• HIGHEST ACCURACY IN POWER INDUSTRY

• 3 PHASE-4 WIRE CONNECTIONS / MEASUREMENT

• DIRECT MEASUREMENT AS PER CT/PT SECONDARY QUANTITIES

- 110V PH TO PH/63.51 V PH-N

- 1 AMP OR 5 AMP

- VA BURDEN NOT >10 ON ANY OF THE PHASES

• WORKS ON REAL TIME CLOCK

• NO CALIBRATION REQUIRED

• TIME ADJUSTMENT FACILITY

• HIGH SECURITY OF DATA STORAGE

Raw dataWEEK FROM 0000 HRS OF 06-01-01 TO 0837 HRS OF 15-01-01NP-0185-A 91858.5 99968.5 39195.5 06-01-01 00 51 +21.57 48 +21.68 50 +21.71 49 +21.33 …. 04 19 +20.61 23 +20.80 19 +21.05 00 +21.35 … 08 00 +24.95 00 +24.95 00 +25.09 00 +24.38 … 12 71 +24.38 52 +23.98 30 +23.81 13 +24.03 …16 00 +23.37 00 +23.52 00 +22.87 00 +21.66 … 20 00 +25.75 00 +25.32 00 +25.40 00 +25.37 … NP-0185-A 94117.2 99968.5 40313.5 07-01-01 00 59 +20.94 54 +21.01 59 +20.79 58 +21.05 … 04 33 +20.05 38 +20.17 37 +20.49 28 +20.90 …08 00 +22.99 06 +23.10 00 +22.81 00 +22.94 … 12 85 +20.93 51 +20.65 21 +20.79 00 +19.89 … 16 07 +20.14 01 +20.53 00 +20.72 00 +20.66 …20 05 +23.62 08 +23.23 16 +23.25 27 +23.40 … NP-0185-A 96172.2 99968.5 41236.9 08-01-01 

Special Energy Meter Various ChecksSpecial Energy Meter Various Checks

CHECKS for DATA VALIDATION :

• NOMINAL VOLTAGE CHECK• FREQUENCY• TIME CORRECTION• WATTHOUR CHECK• PREVIOUS WEEK DATA• ALGEBRAIC SUM

• RAW DATA IN WHr

• MWhr = RAW DATA x CT RATIO x PT RATIO

• PAIR CHECK DONE FOR MAIN/ CHECK/ STANDBY/ FICTMETERS ( ex. : for both sides of ICTs, Lines, GT side & Line side at ISGS.

Special Energy Meter Data ComputingSpecial Energy Meter Data Computing

Reactive Energy Accounting

Reactive Energy is measured

when system voltage is

> 103% of Nominal Voltage< 97% of Nominal Voltage

Loss computations

15 min block-wise % loss =

(Sum of all Injections from ISGS + net IR imports)

X 100

(Sum of all Injections from ISGS + net IR imports) -

(Sum of Drawals by all beneficiaries from Central Grid)

Use of Notional Loss in scheduling

• % Average loss (15 min. blockwise) aggregated over the last week will be used in Scheduling Process for the next week.

(for arriving at the ex-periphery Drawal Schedules of Beneficiaries)

0.5% REDUCTION MEANS MORE THAN 100 CR ANNUAL SAVINGS0.5% REDUCTION MEANS MORE THAN 100 CR ANNUAL SAVINGS

Loss for the week Loss % Week applied for

From To   From To

16-Sep-02 22-Sep-02 4.83 30-Sep-02 6-Oct-02

6-Jan-03 12-Jan-03 3.9 20-Jan-03 26-Jan-03

20-Oct-03 26-Oct-03 3.38 3-Nov-03 9-Nov-03

19-Jan-04 25-Jan-04 3.92 2-Feb-04 8-Feb-04

24-May-04 30-May-04 2.55 7-Jun-04 13-Jun-04

9-Aug-04 15-Aug-04 2.54 23-Aug-04 29-Aug-04

17-Jan-05 23-Jan-05 3.25 31-Jan-05 6-Feb-05

7-Feb-05 13-Feb-05 3.04 21-Feb-05 27-Feb-05

30-May-05 5-Jun-05 2.95 13-Jun-05 19-Jun-05

27-Jun-05 3-Jul-05 3.49 11-Jul-05 17-Jul-05

11-Jul-05 17-Jul-05 3.73 25-Jul-05 31-Jul-05

25-Jul-05 31-Jul-05 3.53 8-Aug-05 14-Aug-05

1-Aug-05 7-Aug-05 3.3 15-Aug-05 21-Aug-05

8-Aug-05 14-Aug-05 2.92 22-Aug-05 28-Aug-05

TYPICAL %AVERAGE LOSS FIGURES FOR CENTRAL GRID IN SR

%Average losses In other Regions :

NR 3.5 to 4.5

ER 3.0 to 3.5

WR 5.0 to 6.0

OTHER REGIONS

%loss for different weeks from 2003- 2005

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51

Week No.

%lo

ss

2003-042004-05

2005-06

REACTIVE ENERGY CHARGE :

PAYABLE FOR :

1. VAR DRAWALS AT VOLTAGES BELOW 97%2. VAR INJECTION AT VOLTAGES ABOVE 103%

RECEIVABLE FOR:

1. VAR INJECTION AT VOLTAGES BELOW 97%2. VAR DRAWAL AT VOLTAGES ABOVE 103%

APPLIED FOR VAR EXCHANGES BETWEEN :

A) BENEFICIARY SYSTEM AND ISTS- THROUGH A POOL ACCOUNT

B) TWO BENEFICIARY SYSTEMS ON INTER-STATE TIES- BY THEMSELVES

RATE: @ Rs. 51.05/MVArh (for 205-06)Basic Rate : 4 paise/kvArh ( for the year 2000-01 )

5% ESCALATION PER YEAR

Issues in Reactive Energy charges

• Deficit in pool (SR & ER)-due to continuous High voltages in SR

Surplus in Pool (NR &WR)

Utilization of Accruals

Disputes in payments between Beneficiaries for Reactive charges in Inter-state Lines

SOUTHERN REGIONAL ELECTRICITY BOARDABT based U.I. AccountFOR A TYPICAL WEEK

NNOTE:

1.     MAPS & KGS not covered under ABT; hence UI reduced to zero, under all conditions.     IR Exchanges:          - Metering points – For WR it is Chandrapur South Bus.

- For ER it is Gazuwaka East Bus & Talcher stage I&II interconnecting bus. ii)              UI for IR exchanges with ER has been calculated at ER frequency.iii)    UI charges with WR and ER has been taken as first charge, as per decision taken in Special Committee meeting held on 17.12.2002.

 

A.     ABSTRACT OF UNSCHEDULED INTERCHANGES ( UI figures in Rs. Lakhs)

Utilities UI

PayableUtilities UI Receivable

KPTCL 720.47741 TNEB 641.48459

KSEB 457.19673 APTRANSCO 269.73260

PONDY 124.38710 ER 188.40533

NLC_II_2 14.72798 RSTPS 84.30154

NLC_II_1 13.81846 GOA 10.67606

TALCHER_II 2.36108 NLC_I_EXP 2.25996

    WR 1.32476

TOTAL1332.9687

6TOTAL 1198.18484

A.     ABSTRACT OF UNSCHEDULED INTERCHANGES (restricting to the lesser of the two as per the 126th SRE Board decision). (UI figures in Rs. Lakhs)Utilities UI Payable Utilities UI Receivable

KPTCL 647.62591 TNEB 641.48459

KSEB 410.96701 APTRANSCO 269.73260

PONDY 111.80962 ER 188.40533

NLC_II_2 13.23876 RSTPS 84.30154

NLC_II_1 12.42120 GOA 10.67606

TALCHER_II 2.12234 NLC_I_EXP 2.25996

    WR 1.32476

TOTAL 1198.18484 TOTAL 1198.18484

payable to Pool

receivable from

APTRANSCO 516417KPTCL 1998690KSEB 231733TNEB 3185840

B.NET REACTIVE ENERGY CHARGES BETWEEN BENEFICIERIES:

280

0

APTRANSCOKPTCLKSEBAPTRANSCOKPTCL

11,410

0235,924

KPTCLTNEB

00

TNEBGOA

04,853

APTRANSCOKSEB

0APTRANSCO0

TNEBPONDY

0

A.REACTIVE ENERGY CHARGES WITH THE POOL :

( Amount in Rupees)

BY BENEFICIERY

FROM BENEFICIERY

KPTCL

AMOUNT RECEIVABLE

in Rupees

Beneficiaries Beneficiaries

GOA

KPTCL

KSEB

TNEB

PONDY

0

(as per decision in the 132nd meeting of SRE Board)