Transmission & Distribution: Indian Scenario - An Overview

1. Transmission & Distribution: Indian Scenario - An Overview S.C. Misra Director(Projects) Power Grid Corpn. of India Ltd.

2. Power System in India • Electricity is a concurrent subject- • both State and Central Govt. responsible for development & management of this sector • State Electricity Boards (SEBs) responsible for wheeling of power from state generating units and state level IPP’S • POWERGRID – the Central transmission utility wheels power of central generating utilities and interstate mega IPP’s • Power distribution responsibility is generally with SEB’s / Private distribution utilities • 3 levels for Grid management system adopted namely State, Regional & National (under progress)

3. Hierarchy of Indian Power System

4. Power Scenario - Present • Installed capacity - 107,000 MWCoal – 71% Hydro – 25% Nuclear & others – 4% • Peak demand Peak power - 82,000 MW Energy (average) - 1430 MU/day • Availability Peak power - 71,260 MW Energy (average) - 1325 MU/day • Shortage Peak power - 10,300 MW (12.6%) Energy - 107 MU/day (7.5%)

5. Transmission - Present • Figs. are in ckt. km • State Central Total (POWERGRID) • HVDC 1,504 4,420 5,924 • 800 KV 400 550 950 • 400 kV 13,000 39,000 52,000 • 220/132 kV 2,06,000 9000 2,15,000 • Transmission loss: 3 - 4% considered reasonable as per international standards. • Application of State-of-the-art technologies - HVDC bipole, • HVDC back-to-back, SVC, Series Compensation, FACTS etc. • Application of improved O&M technologies– Hotline maintenance, Emergency Restoration System, Thermovision scanning etc.

6. Demand - Supply Scenario – by 2012 • Projected Peak Demand - 157,000 MW (as per 16th EPS) • Capacity addition envisaged– • In 10th Plan - 45,000 MW • In 11th Plan - 55,000 MW

7. Regional to National level Planning • Uneven disposition of energy resources • Major Hydro resources in Arunachal Pradesh, H.P and J&K • Coal reserves mostly in Bihar/Orissa/West Bengal • Unbalanced growth of different regions • Surplus situation in Eastern Region, while deficit in others • Difficulties in day-to-day operation • Optimisation of generation capacity addition • Utilising time diversity • Spinning reserve optimisation, mutual support • Poor Hydro-thermal mix • Poor ratio – 25:75, Eastern Region – 12:88

9. Future Transmission – Strategy Change in approach • Bulk power transmission over long distances • Transmission Planning & development at National level • Establishment of sufficient no. of inter-regional links inter-connecting different regions

10. Major Considerations • Conservation of Right-of-Way • Avoidance of Forest • Flexibility to accommodate uncertainty in generation addition • Minimisation of Transmission cost

11. Technology Integration • Large investment is required • Scarcity in Right-of-Way • Hence, there is a need to optimally utilise the existing transmission infrastructure by enhancing transmission capacity

12. Technology for optimal utilisation • Series compensation /FACTS like TCSC • Line can be loaded upto its Thermal capacity. • Higher final Conductor Temperature – 850/ 950C • Uprate loadability to about 30-50% more than existing 750C . • Increase in capital cost 1-2% • Multi-conductor bundle (tripple/quad.) • Bulk power transfer over moderate distance. • Uprating of line by using Alternate Conductor System • High temp. endurance (200 deg C)conductor like INVAR, ACSS, Gap etc.

13. Upgradation to Higher voltage • Upgrading the existing lower voltage line to next higher voltage increases power transfer capacity with less investmentand practical option. • POWERGRID has developed design and done actual case studies for upgradation of • 66 kV D/c to 132 kV D/c • 132 kV D/c to 400 kV S/c • 220kV D/c to 400 kV S/c • Upgradation of Kishtwar - Kishenpur 220 kV D/c to 400 kV S/c line is being carried out by POWERGRID to increase power transfer capability by 1.8 times

14. Technology for future expansion • Utilisation of existing capacity will not be sufficient to meet the long term transmission requirement • Adoption of following technologies would also be required: • Next higher transmission voltage – 800kV • Hybrid EHVAC and HVDC system • Compact lines

15. Next Higher voltage • 765 kV already introduced as next higher voltage • largetransfer capacity, low losses, lower cost/MW/km • Suitable for evacuation from Mega projects • Reasons: Large unit size, scope for immediate future generation expansion, less R-O-W & compensation, availability of strong 400 kV underlying network. • Needs careful attention on Insulation Design, Reactive Power Management and Operational aspects • More than 75% reactive compensation. • Chances of resonant-overvoltages. • Voltage controlled switched shunt reactors. • Maintain large source strength.

16. HVDC Transmission • Long distance point-to-point bulk power transmission • Asynchronous HVDC links are already under operation • Talcher-II Transmission System • Generation in ER, beneficiaries in SR situated about 1500 kms. away • Would acts as separator between SR and the rest of synchronously connected grid. • Power transfer capacity of the order of 3000MW over long distance is already under operation with higher voltage like  600kV in the world

17. Compact Lines • Guyed V tower, Chainette tower etc. can be adopted so that space occupied by the tower base can be reduced. • Compactness in the line by • Optimisation of clearances • Use of insulated cross-arms • Phase spacers. • Compactness would increase SIL by 15-20% of traditional line • POWERGRID already designed 400kV compact line

18. PLAN FOR NATIONAL GRID - A PHASED DEVELOPMENT Phase – 1 – Already completed in 2002 • Interconnection of Regional Grids through HVDC Back-to-Back links having cumulative capacity of 5000 MW Phase – 2 – Partly completed – by 2006-07 • Hybrid system comprising of high capacity HVDC and HVAC lines (both 765 kV and 400 kV) • 2000MW, 1400kms long HVDC bipole between Eastern and Southern regions – completed • 400kV synchronous interconnections between Eastern and Western regions resulting into synchronous operation of power system having 50,000MW capacity - completed • Most of transmission lines would be part of associated transmission system of large sized generation project. • Cumulative inter-regional capacity would be 23,000 MW Phase – 3 – to be completed by 2012 • Ring of 765 kV transmission lines inter-connecting ER, WR and NR • Cumulative capacity would be 30,000 MW

20. Growth of Energy exchange between ER & Other Regions • All India energy exchange in 2002-03 : 12000 MU

21. Benefits of inter-regional energy exchange • For transfer of surplus power from ER to other regions, inter-regional links being developed progressively • In 1996-97, total inter-regional transfer capacity was 1200MW, which is now 8000MW • Inter-regional energy exchange increased to 12000MU in 2002-03 out of which 9000MU from ER • Export of energy from ER leads to • Saving in fixed cost for ER constituents by about Rs. 1350 Cr. • Average 2000MW power exported from ER. Hence, investment of about Rs. 8000 Cr. deferred against addition of equivalent generation capacity by deficit regions.

22. Benefits of National Grid • Reduction in capacity addition requirement by about 13750 MW--- hence saving on investment of Rs. 55,000 crore. (due to peak time diversity and saving in spinning reserve) • Saving in operational cost – Rs. 1200 Cr per annum • Transmission highway would enable setting up of large pit head stations having lower cost of energy Savings on account of this -Rs. 9000 crores per annum. • In addition, Nation’s investment towards fuel transportation infrastructure could be avoided. • Better overall hydro-thermal mix • Very low for ER and WR ( ER – 15 : 85, WR - 17 : 83 ) – affecting grid operation • With National Grid, it would become 33 : 67 on all India basis.

23. Phase – II & III

24. Growth of Cumulative capacity of Inter-regional links

25. Present State of Distribution • Distribution is the Weakest link in the entire power chain • Distribution is characterised by inefficiency – • High losses – both technical and non-technical • Inadequate metering • Interruption on power supply • Unplanned growth – weak network • Poor quality • Tardy record in billing and revenue collection – weak financial health of utilities

26. Distribution Reforms • APDRP initiated by GoI to improve the distribution system in the country with following objectives : a) Make the distribution circles commercially viable by reducing the aggregate Technical and Commercial loss (ATC) b) Improvement in quality of power supply c) Customer satisfaction • Govt. of India budgeted an outlay of about Rs. 40,000 Crores for next 5 years. • Govt of India appointed POWERGRID & NTPC as lead Advisor cum Consultant (AcC)

27. POWERGRID’s Role in APDRP • POWERGRID assigned 81 nos. of circles in 18 States all over the country • For these circles schemes for improvement in distribution system approved by MOP at total cost of about Rs 5000 Crores. Schemes covers – • 100% metering at consumers & system level • Energy Audit and Accounting • Upgradation/strengthening of sub-transmission and distribution network including revamping of S/s and DTs • In addition schemes of about Rs.850 crores being executed by POWERGRID in various States on bilateral agreement basis. • POWERGRID is also carrying out Rural Electrification works in about 2600 villages in Bihar

28. Thank You Thank You