1. The document discusses the status of HVDC links in India and abroad. It provides a history of HVDC technology and describes several existing and upcoming HVDC projects in India such as the 800kV multi-terminal system and India-Bangladesh interconnector project. 2. Major HVDC projects discussed overseas include the Itaipu project in Brazil, which holds the world record voltage of ±600kV, and underwater HVDC links like the Gotland wind power project in Sweden and the Leyte-Luzon link in the Philippines. 3. HVDC transmission is concluded to be an economical and environmentally-friendly technology that is becoming viable for lower power levels and shorter distances due to new

1. STATUS OF HVDC LINKS
(IN INDIA AND ABROAD)
ABHISHEK PRATAP SINGH
B.Tech,EN-A, 1403221006

2. INDEX
• History of HVDC
• Introduction
• HVDC systems currently in India
• Upcoming HVDC projects in India
• HVDC projects in abroad
• Conclusion

3. HISTORY OF HVDC
• Hewitt´s mercury-vapour rectifier, which appeared in 1901.
• First commercial HVDC transmission, Gotland 1 in Sweden in
1954.
• First solid state semiconductor valves in 1970.
• First microcomputer based control equipment for HVDC in
1979.
• Highest DC transmission voltage (+/- 600 kV) in Itaipú, Brazil,
1984.
• First active DC filters for outstanding filtering performance in
1994.
• First Capacitor Commutated Converter (CCC) in Argentina-
Brazil interconnection, 1998
• First Voltage Source Converter for transmission in Gotland,
Sweden ,1999

4. INTRODUCTION
HVDC LINKS
A high-voltage direct current(HVDC) transmission Link primarily
consist of a converter station in which the AC voltage of a
conventional powergrid is converted into DC voltage, a
transmission line , and another converter station on the other
end , where the voltage is converted back into AC.

5. ADVANTAGES OF HVDC LINKS
 Direction of power flow can be changed very quickly (bi-
directionality).
 HVDC can carry more power for a given size of conductor .
 HVDC transmission has typically 30-50% less transmission
loss than comparable alternating current overhead lines.
 As a “firewall”, HVDC can prevent the transmission of faults
between connected AC grids and hence can prevent
BLACKOUTS.

6. CONT…
 For lengths of about 600 km or more, overhead lines using
HVDC transmission technology are more cost-effective than
AC technology.
 Interconnecting two AC networks in an asynchronous
manner.
 For underground or submarine cables, hardly any electricity
is delivered when AC lines are 80 km or longer (The cable
capacities absorb the usable electricity).

7.  Generally, an HVDC transmission link has two poles (and also
two lines between them) over which half of the electricity is
transmitted. If one pole or line were to fail, half of the
remaining power would still be available.
 There is also the space saving variant HVDC Plus, which is
used especially on offshore platforms. In addition, HVDC Plus
is the HVDC solution for built-up urban environments as can
be encountered in San Francisco, for example.

8. COMPARISON AC & DC LINE

9. TYPES OF HVDC LINKS
• MONO-POLAR LINKS
• HOMO-POLAR LINKS
• BI-POLAR LINKS
• MULTI-TERMINAL

10. NATIONAL GRID -PRESENT
Inter -Regional Capacity: 22,400MW

11. ENERGY RESOURCES IN INDIA

12. TRANSMISSION HIGHWAYS

13. INCREASE IN TRANSMISSION
VOLTAGE

14. 1. HVDC Systems presently in
operation in India

15. 1.1 RIHAND – DADRI HVDC PROJECT
 Date of commissioning : Dec 1991
 Power rating : 1500MW
 No. of Converter Transformers : 2
 AC Voltage : 400 kV
 DC Voltage : +- 500 kV
Converter Transformer
 Rihand Terminal : 6 x 315 MVA
 Dadri Terminal : 6 x 305 MVA
 Length of over head DC line : 816 km

16. FEATURES OF SYSTEM
 Bi-Pole Transmission link supplies Bulk power from Thermal
Power Plant of Rihand (Eastern part of Northern Grid) to
Dadri (Western part of Northern Grid).
 Each pole continuous power carrying capacity is 750 MW
with 10% two hours overload and 33% five seconds overload
capability .
 Reverse power flow capability available.

17. 1.2 VINDHYACHAL BACK TO BACK HVDC
STATION
 Completion date : April 1989
 Power rating : 2 x 250 MW
 No. of Blocks : 2
 AC Voltage : 400 kV
 DC Voltage : ± 70 KV
 Converter Transformer : 8 x 156 MVA

18. System Salient Features
 It connects Vindhyachal Super Thermal Power Stations
(Western Region) to Singrauli Super Thermal Power Stations
(Northern Region) in Indian Grid.
 First commercial Back to Back HVDC Station in India.

19. 1.3 HVDC Chandrapur Back to Back
Station
 Completion date : Dec 1997
 Power rating : 2 x 500 MW
 No. of Blocks : 2
 AC Voltage : 400 kV
 DC Voltage : 205 kV
 Converter Transformer : 12 x 234 MVA

20. System Salient Features
 It connects Chandrapur Thermal Power Stations (Western
Region) to Ramagundum (Southern Region) Thermal Power
Stations in Indian Grid.
 Second commercial Back to Back HVDC Station in India.

21. 1.4 HVDC Talchar- Kolar Transmission Link
 Completion date : June 2003
 Power rating : 2000 MW
 No. of Poles : 2
 AC Voltage : 400 kV
 DC Voltage : + 500 kV
Converter Transformer
 Talcher : 6 x 398 MVA
 Kolar : 6 x 398 MVA
 Length of over head DC line : 1369 km
 This is the longest (1369 Km.) commercial HVDC link in India.

22. 1.7 HVDC Ballia – Bhiwadi Transmission
Link.
Commissioned on : Feb 2010
 Power rating : 2500 MW
 No. of Poles : 2
 AC Voltage : 400 kV
 DC Voltage : + 500 kV
 Length of over head DC line : 780 Km.
Converter Transformer
 Ballia : 8 x 498 MVA
 Bhiwadi : 8 x 498 MVA

23. Switchable Configuration of Spare
Converter Transformer
 Arrangement of Spare Converter Transformer for quick
restoration of Pole in case of failure of Converter
Transformer.
 Each Pole is having a dedicated Spare Converter
Transformer with switching arrangement.
 Transformer Configuration being used for the first time.

24. • UPCOMING HVDC PROJECTS IN INDIA

25. 800 KV HVDC Multi Terminal System

26. CONT….
 POWERGRID is installing +/-800 kV, 6000 MW HVDC multi-
terminal system of approx length of 1728 km from North
Eastern Region to Agra.
 One Rectifier station in Biswanath Chariali (in North Eastern
Region), second one in Alipurduar (in Eastern Region) and
Inverter station at Agra (in Northern Region).
 This Tr. System originates from Assam and passes through
West Bengal, Bihar and terminates in Uttar Pradesh .
 First Multi Terminal project in India.

27. CONT….

28. Salient features multi-terminal HVDC
project
 First ±800 KV Multi-Terminal HVDC project in the world.
 First 12 pulse 800 KV terminal of the world.
 After considering the continuous 33% overload feature, this
will be the highest capacity HVDC project of the world.
 Each pole of the Multi-terminal shall be designed for
2000MW which is the highest capacity poles in the world.

29. 1 X 500 MW India Bangladesh
Interconnector project

30. India – Sri Lanka Interconnection
 ± 400 kV, 4 x 250 MW HVDC Bipole Transmission Link.
 From Madurai (India) to Sri Anuradhapura (Sri Lanka).
 Project having Overhead line (app 334 km) and Submarine
Cable ( app 90 Km).

32. 2. HVDC PROJECTS IN ABROAD

33. Itaipu HVDC Transmission Project in
Brazil
• It has a total rated power of 6300 MW and a world record
voltage of ±600 kV DC.
• Length of overhead DC line: 1600 km approx.
• HVDC was chosen partly to be able to supply power from the
50 Hz generators to the 60 Hz system, and partly because an
HVDC link was economically preferable for the long distance
involved.

34. GOTLAND WIND POWER EVACUATION
• Swedish island of Gotland, in the Baltic sea has wind farms.
• Underground DC cables used.
• Power rating: 50 MW DC
• Voltage: ± 80 kV
• Length of DC cable: 70 km
• Main reasons for choosing HVDC system: Environmental
aspects and power quality.

35. Leyte - Luzon HVDC Power
Transmission Project, Philippines
• 440 MW, 350 kV monopolar HVDC link.
• Power transfer from the geothermal power plant on the island
of Leyte, to the southern part of the main island of Luzon to
feed the existing AC grid in the Manila region.
• Length of overhead line: 430 km
• Length of submarine cable: 21 km

36. CONCLUSION
• HVDC systems remain the best economical and environmentally
friendly .
• New technologies, such as the VSC based HVDC systems, and the
new extruded polyethylene DC cables, have made it possible for
HVDC to become economic at lower power levels (up to 200 MW)
and over a transmission distance of just 60 km.
• Dynamics - technology development, and a quantum leap in efforts
to conserve the environment - are demanding a change in thinking
that could make HVDC systems the preferred alternative to high
voltage AC systems in many other situations as well.