The document summarizes a seminar presentation on HVDC (high voltage direct current) transmission. Some key points: - HVDC transmission has advantages over HVAC like lower transmission losses over long distances. The first HVDC link was between Gotland and mainland Sweden in 1954. - HVDC uses direct current instead of alternating current to transmit electricity over long distances. It requires only two conductors instead of three. Losses are also lower compared to HVAC. - HVDC transmission can be classified as homopolar, monopolar or bipolar depending on the conductor configuration. Early HVDC projects in India included the Rihand-Delhi and Chandrapur-Padghe lines which helped transmit

1. A
SEMINAR ON
“HVDC TRANSMISSION”
SUBMITTED
BY
Utkarsh J. Jambhule
(BE12FO3FO25)
UNDER THE SUPERVISION OF
Dr. Archana G. Thosar (H.O.D)

2. INTRODUCTION:
With the increasing of requirement of electrical power
supply the facilities have to be increased in that
transmission plays an important role.
Here HVDC (high voltage direct current) transmission
plays major role in power transmission.
First HVDC transmission linked between gotland and
mainland in sweden in 1954.
The HVDC transmission has many advantages over
HVAC transmission.

3. HVDC MEANS…..
HVDC stands for High Voltage Direct Current and is
today a well-proven technology all over the world.
 Two AC systems having different frequencies can be
linked up together by means of HVDC link.
 HVDC technology is used to transmit electricity over
long distances.

4. WHY DC TRANSMISSION ?
Losses are less in DC transmission while comparing to
AC transmission.
Only two conductors are required for DC with
positive and negative polarities.
DC overhead lines or cables are less
expensive.
DC lines are useful for long distances above
500km.
?

5. Comparison of HVAC and HVDC
 Conventionally power transmission is affected
through HVAC systems all over the world.
 HVAC transmission is having several limitations like,
line length , uncontrolled power flow, over/low voltages
during lightly / over loaded conditions, stability
problems, fault isolation etc…
 But HVDC have low transmission losses and it
requires only two conductors.

6. Comparison between the prices of AC & DC
Transmission

7. Wind
Power
AC
Transmission
Line
Converter
Station
Inverter
Station AC
Transmission
Line
Distribution
Line
HVDC
Transmission Line
HVDC transmission system

8. 1. Converters
2. Smoothing reactors
3. Harmonic filters
4. Reactive power source
5. Electrodes
6. Dc lines
7. Ac circuit breakers

10. Homopolar link
Monopolar link
Bipolar link
HVDC Transmission can be broadly classified
into:-

11. It uses one conductor.
The return path is provided by ground or water.
Use of this system is due to cost considerations.
A metallic return may be used where earth resistivity is too high

12. Each terminal has two converters of equal rated voltage,
connected in series on DC side.
The junctions between converters is grounded.
If one pole is isolated due to fault, the other pole can operate
with ground and carry half the rated load ( or more using
overload capabilities of its converter line.)

13. It has two conductors each having same polarity, usually negative.
Since the corona effect in DC transmission lines is less for
negative polarity, homopolar link is usually operated with negative
polarity.
The return path for such a system is through ground.

14.  Back to Back Transmission.
 Point to point Overhead line
Transmission.
 Point to point Underground Cable
Transmission.
 Point to point Sub marine
Transmission.

19.  The losses which occurs in the
systems are comparatively low at all the
stages (i.e.) at generation , transmission
& distribution level.
 The losses at transmission level can
be highly reduced by HVDC
transmission.

20. Advantages of HVDC
Technical
Advantages
Economic
Advantages

21.  Lesser Corona Loss and Radio interference.
 The voltage regulation problem is much less
serious for DC, since only the IR drop is
involved. For the same reason steady state
stability is no longer a major problem.
 No skin and proximity and Ferranti effect
 Asynchronous operation possible between
regions having different electrical parameters.

22.  DC lines and cables are cheaper than AC lines
or cables.
 The towers of the DC lines are narrower,
simpler and cheaper compared to the towers of
the AC lines.
 Line losses in a DC line are lower than the
losses in an AC lines.

23.  The disadvantages of HVDC are in conversion,
switching, control, availability and maintenance.
 There is nothing like DC transformer which can
change the voltage level in a simple way. Voltage
transformation has to be provided on the AC sides of
the system.
 The required converter stations are expensive and have
limited overload capacity.

24. Rihand-delhi and chandrapur-padghe were the first long
distance hvdc projects in India.
 In 1990 ,rihand-delhi (singrauli) thermal power complex
with a combined power generation of Several thousand
MW was put in to service. it covers over a distance of 814
km.
The 1500 MW transmission chandrapur-padghe was put
in to service. it covers over distance of 736 km.
APPLICATIONS OF HVDC TRANSMISSION IN INDIA:

25. Conclusion
 Recent studies indicate that HVDC systems are very
reliable.
 Very large investments Eg. In China and India shows that
High Voltage Direct Current will very important in the
future, especially in big and new-industries countries.

26. 1.C.L.wadhwa ‘electrical power systems'-third edition
2. I.J.nagrath and d.p.khotari 'power system engineering
3. S.S. vadhera 'power system analysis and stability
4. Soni gupta bhatnagar 'power system engineering
5. K.R.padiyar ‘hvdc power transmission systems'
BIBLIOGRAPHY: