Why Intra – State ABT • Intra-state ABT is a techno-economic • tool for bringing rational tariff structure for supply of electricity from State generators to the distribution Licensees. • It is a mechanism for enforcing discipline in the Grid.
Benefits of Intra – State ABT • a) Benefits to the Power System • Brings about grid discipline by maintaining frequency in prescribed band (49.5 to 50.5 Hz). • Ensures optimum utilization of available generation capacities. • Enhances opportunities for Open access, and Trading of electricity. • Scope for encouraging competition among generators.
b) Benefits to the Generator • Encourages maximization of Generation during peak hours with incentives and discourages the same during off-peak hours with penalties linked with frequency. • Enables systematic scheduling in terms of long term, short term as well as day ahead, duly considering plant availability and maintenance. • Ensures better life of equipments due to efficient management of Demand Vs Supply. Thereby the ‘Hidden Costs’ due to damage is avoided. • The three-part Tariff under ABT provides for proper recovery of fixed and variable costs of Generator.
c) Benefits to the Distribution Licensees • Economic efficiency dictates that the least cost power should be dispatched in preference to costly power (Merit Order Dispatch). ABT provides for the same. • Licensees can plan their requirement, both for peak and off peak demands. • Enables efficient Load Management through their own Area Load Dispatch Centers.
d) Benefits to the End Users • Enables open access, captive generation and trading of electricity. • Ensures quality and reliable power supply. • Scope for reduction in cost of power due to licensees opting for merit order dispatch in their scheduling.
CONSTITUENTS OF INTRA-STATE ABT in RAJASTHAN • JVVNL • AVVNL • JdVVNL • RVUN
ABT BILLING METHODOLOGY • ABT is, basically, a three part tariff system consisting of the following components :- • Fixed charges – on monthly basis subject to adjustment on yearly basis. • Variable charges - on monthly basis. • Unscheduled inter-change (UI) charges. – on weekly basis.
UNSCHEDULED INTER-CHANGE (UI) CHARGES • The UI fora Generating Stationshall be equal to itsactual generationminus itsscheduled generation. UI forStatesshall be equal to itstotal actual drawalminus itstotal scheduled drawal. • UI shall be worked out for each 15 minutes time block. Charges for all UI transactions are based on average frequency of the time block. • The UI Tariff structure w.e.f., 07/01/2008 is as under. Average Frequency of time-block UI Rate (P/kWh) ---------------------------------------- ----------------------------------- 50.5 Hz and above 0.00 Below 50.50 Hz and upto 50.48 Hz 8.00 Below 49.82 Hz and upto 49.80 Hz 280.00 Below 49.04 Hz and upto 49.02 Hz 982.00 Below 49.02 Hz 1000.00 Between 50.50 Hz and 49.80 Hz Linear in 0.02 Hz steps @ 8 P/kWh for each step Below 49.80 Hz Linear in 0.02 Hz steps @ 18P/kWh for each step
INTRA-STATE UI RATE UIS = UIR / (1-L) Where, UIS is Intra State ABT rate for a frequency step UIR is UI rate applicable for Northern Region for that frequency step L is the Inter-State transmission losses of NR in per unit
UI SETTLEMENT MECHANISM IN INTRA-STATE ABT At Inter – state level the Unscheduled interchanges of Inter regional sources are determined with reference to their schedule at the point of injection but those of SEBs with reference to their ex-periphery schedule. Datum for working out UI not being same for all entities, this results in UI MISMATCH which is equalised by averaging the two ON DAILY BASIS. The above adjustment is required to equalize payable UI amount to receivable UI amount so that UI pool account is maintained as a Zero balance account.
METHODOLOGY FOR ZERO BALANCING THE UI POOL ACCOUNT AT INTER-STATE LEVEL • UI AMOUNT IS DRAWN FOR ALL THE UI POOL MEMBERS ON ACTUAL BASIS. • FROM THE UI ACCOUNT AMOUNT RECEIVABLE MEMBERS AND AMOUNT PAYABLE MEMBERS TO THE POOL IS SEPERATELY DRAWN OUT. • AMOUNT PAYABLE AND RECEIVABLE WILL NOT MATCH BECAUSE FOR GENERATORS THE UI IS DRAWN OUT BASED ON INJECTION & SCHEDULE AT GENERATOR PERIPHERY WHEREAS FOR STATES THE SAME IS BASED ON DRAWAL & SCHEDULE AT STATE PERIPHERY. • AS PER THE CERC STIPULATION THE UI POOL ACCOUNT SHOULD BE A ZERO BALANCE ACCOUNT. • 5. THE UI MIS-MATCH IS CALCULATED ON DAILY BASIS AND APPORTIONED TO ALL UI POOL MEMBERS IN THE RATIO 50:50 TO THE PAYING AND RECEIVING MEMBERS IN THE RATIO OF THE ORIGINAL UI AMOUNT DRAWN OUT. • 6. A CASE STUDY BASED ON THE ABOVE METHODOLOGY FOR 19-3-2007 UI ACCOUNT ISSUED BY NRPC IS SHOWN IN THE NEXT SLIDE.
SAMPLE CASE FOR 19TH MARCH 2007 ACTUAL UI AMOUNT FOR PAYEE AND RECEIVING CONSTITUENTS
METHODOLOGY FOR ZERO BALANCING THE UI POOL ACCOUNT AT INTER-STATE LEVEL • MIS-MATCH BETWEEN THE PAYABLE AND RECEIVABLE AMOUNT FROM THE UI ACCOUNT IS (903.0818-820.2534)= 82.8285 LACS RUPEES. • THIS DIFFERENCE IS DIVIDED EQUALLY BETWEEN THE TWO i.e. PAYING & RECEIVING ENTITIES IN THE RATIO 50:50 AMOUNTING TO 41.41423 LACS RUPEES EACH. • SINCE NO INTER-REGIONAL LINK IS AMONGST THE RECEIVING UTILITES 41.41423 LACS IS DIVIDED AMONGST ALL THE RECEIVING UTILITIES IN PROPORTION TO THEIR UNADJUSTED UI AMOUNT. • AMONGST THE PAYING UTLITIES EXCLUDING THE INTER- REGIONAL LINKS THE AMOUNT OF 41.41423 LACS IS CREDITED TO ALL IN PROPORTION TO THEIR UNADJUSTED UI AMOUNT. • THE ADJUSTED ACCOUNTS ARE DISPLAYED IN THE NEXT SLIDE.
In Intra – State ABT also the UI account should be a Zero Balance Account which indicates UI payable/receivable to/from the Regional UI pool account should be equal to the UI receivable/payable in the Intra-State UI pool Account.The following mechanism is proposed :1. SLDC shall draw-out the Intra-state UI account in same principle as that of Inter-state UI account.2. The amount payable / receivable to the Regional pool account would then be equated on the basis of Intra-state ABT amount. METHODOLOGY FOR ZERO BALANCING THE UI POOL ACCOUNT AT INTRA-STATE LEVEL
SAMPLE CASE FOR INTRA-STATE ABT SETTLEMENT ACTUAL UI AMOUNT FOR PAYEE AND RECEIVING CONSTITUENTS calculated for dated 18/02/2008
METHODOLOGY FOR ZERO BALANCING THE UI POOL ACCOUNT AT INTER-STATE LEVEL • MIS-MATCH BETWEEN THE PAYABLE AND RECEIVABLE AMOUNT FROM THE UI ACCOUNT IS (409.327-404.246)= 5.081 LAC RUPEES. • THIS DIFFERENCE IS DIVIDED EQUALLY BETWEEN THE TWO i.e. PAYING & RECEIVING ENTITIES IN THE RATIO 50:50 AMOUNTING TO 2.540 LACS RUPEES EACH. • AMONGST THE RECEIVING UTILITES 2.540 LACS IS DIVIDED AMONGST ALL THE RECEIVING UTILITIES IN PROPORTION TO THEIR UNADJUSTED UI AMOUNT. • AMONGST THE PAYING UTLITIES EXCLUDING THE INTER- STATE ACCOUNT THE AMOUNT OF 2.540 LACS IS CREDITED TO ALL IN PROPORTION TO THEIR UNADJUSTED UI AMOUNT. • THE ADJUSTED ACCOUNTS ARE DISPLAYED IN THE PREVIOUS SLIDE.