1. HVDC LIGHT:- NEW TECHNOLOGY FOR A BETTER ENVIRONMENT
By,
NAGASHREE K [1DA06EE024]

2. CONTENTS INTRODUCTION HVDC Light Technology HVDC Light Basic Principle
HVDC Light Characteristics
HVDC Light Cable
REASONS BEHIND A CHOICE OF HVDC
DIFFERENCE B/W HVDC LIGHT AND CLASSICAL HVDC
ADVANTAGES
HVDC LIGHT APPLICATION
CONCLUSION

3. INTRODUCTION
HVDC Light is a unique and proven power transmission, specially designed to transmit power underground and underwater and is It is friendly to the environment.
It offers numerous environmental benefits, including “invisible” power lines, neutral electromagnetic fields, oil- free cables and compact converter stations.
The potential of the technology to meet special requirements in centralized low and medium power grids.
Its preference over other transmission systems, AC in particular, and its application for better quality of power delivery.

4. HVDC Technology
HVDC Light technology is well suited to meet the demands of competitive power market for transmission up to 330MW and for DC voltage in the ± 150kV range.
It consists of two AC to DC converter stations and a pair of underground cables interconnecting each converter station.
The AC to DC converters employs the latest in power semiconductor technology, the IGBT and is based on Voltage Source Converters which has characteristics well suited to meet the demands from the new markets.

5. HVDC Light Basic Principle
Conventional HVDC
Converter technology is
Based on the use of
Line commuted
convertrs. The key part
of the HVDC Light
converter consists of
An IGBT valve bridge.
1. No special converter transformers are necessary b/w the valve bridge and AC grid.
2. A small shunt AC filter is placed on the AC side of reactor. On DC side there is a DC
capacitor that serves as a DC filter too

6. Main Circuit Diagram

7. HVDC Light Basic Characteristics
Independent control of active and reactive power
Feeding of power into passive networks ( i.e. network without any generation)
Power quality control
Modular compact design, factory pre-tested
Short delivery times
Reloadable/Leasable
Unmanned operation
Robust against grid alterations

8. HVDC Light Cable
Marine Cable
Terrestrial Cable

9. Magnetic fields are eliminated since HVDC Light® cables are laid in pairs with DC currents in opposite directions.
Risk of oil spill, as in paper-oil-insulated cables, is eliminated.
The cable insulation is PE based and not dangerous.
The cable metals can be reused.

10. HVDC Light Cable development

11. THE REASONS BEHIND A CHOICE OF HVDC INSTEAD OF AC
Lower investment cost in transmission and terminal station.
Unlike AC cables, which generally have a technical limit of around 100km due to reactive power and losses, DC-cables have no technical limit to distance.
An optimized HVDC transmission line has lower losses than AC lines for the same power capacity.
When considering the cost of installing an HVDC Light underground transmission it is important to consider the total life cost benefits and not just the initial up front capital

12. Difference b/w HVDC Light and classical HVDC
Power range: Classical HVDC is most cost effective in high power range, above approx some 250 MW HVDC Light , comes in unit sizes ranging from a few tens of MW up to presently 550 MW.
Independence of AC n/w: HVDC light does not rely on the AC network’s ability to keep the voltage and frequency stable. HVDC Light can feed load into a passive network.
Modular: HVDC Light is based on a modular concept with a number of standardized sizes for the converter stations. Most of the equipment is installed in enclosures at the factory. Conventional HVDC is always tailor made to suit a specific application.

13. 4. Active and reactive power control: Classic HVDC terminals can provide limited control of reactive power by means of switching of filters and shunt banks. The HVDC Light control makes it possible to create any phase angle or amplitude, which can be done almost instantly.
5. LOW POWER OPERATION AND POWER REVERSAL: The HVDC light converter can operate at very low power, The power reversal is obtained by changing the direction of the DC current and not by changing the DC voltage.

14. Advantages of HVDC light
Reduced environmental impact, an underground cable has no visual impact on the landscape.
Faster and easier issue of permits using DC underground cables. Underground cables rarely meet with public opposition and often receive political support.
HVDC Light® cables have extruded polymer insulation. Their strength and flexibility make the HVDC Light® cables well suited for severe installation conditions both underground as a land cable and as a submarine cable

15. Cond…
Shore grid strengthening:- A further possible use for HVDC Light in offshore wind farm applications The grid is sometimes rather weak (radial structure) along the coastline. An HVDC Light can then be assigned the task of strengthening the Points of Common Connections
The width of the corridor to install the underground cable can be as narrow as 4 meters, which will give greater flexibility with the selection of a transmission route.
As there is no need to maintain wide distances between groups of cables, DC cables can be ploughed direct in the ground or laid together in narrow trenches.

16. HVDC Light Applications
Underground power links
Connecting wind farms
Powering islands and remote loads
Interconnecting networks
City center in feed
Oil and gas offshore platforms
Multiterminal HVDC Light grid

17. Conclusions
The conclusion was that the HVDC Light fulfilled the technical requirements and that there is a great potential to further exploit the controllability of the converters. HVDC Light is the ultimate tool to enhance performance and interaction with the complex environment. The advantages include its modularity, standardized design leading to short delivery times, and compact stations and cables reducing environment impacts .

18. THANK YOU