29-06-2012, 03:27 PM
RECENT TRENDS IN HVDC TECHNOLOGY
[attachment=26136]
INTRODUCTION
A high-voltage, direct current (HVDC) electric power transmission system uses direct current for the bulk transmission of electrical power, in contrast with the more common alternating current systems.
During the latest 20 years, HVDC has become the dominating technology for long distance transmission of bulk power.
The use of 800 kV HVAC that was introduced in several countries during the 1960´s and 1970´s has come to a halt.
The rapid development and the increased confidence in the HVDC technology have caused the transition from ac to dc.
HVAC SYSTEM
Overhead AC transmission is the standard technology for electric power transportation. Traditionally it was preferred over any other transmission technology, especially in rural areas.
No other technology can compete with overhead AC transmission in terms of cost. Technically and economically, overhead AC transmission provides an advantageous solution.
HVDC SYSTEM OVERVIEW
Direct current is put to use in common life for driving our portable
Devices, UPSs, battery systems and vastly in railway locomotives.
If DC is required to be used for transmission & since our
primary source of power is AC the following are the basic steps:
Rectifier (convert AC into DC)
Dc tr. lines (transmit DC)
Inverter (convert DC into AC)
ORIGIN OF HVDC TECHNOLOGY
The first commercially generated electricity by Thomas Alva Edison in the 1880s was DC at low voltage levels.
The AC system by Nikola Tesla made it possible to easily transform
the voltage to higher voltage levels, suitable for transmission of electric
power over long distances.
The development of the mercury arc valves in the 1930s improved the technology and in 1945 a commercial HVDC system in Berlin was commissioned
In 1954 the first commercial HVDC transmission was put into operation with a 96 km sea cable, 20 MW, between the Sweden mainland and the island of Gotland.
CONCLUSION
It is by now clear that HVDC transmission is already a reliable, efficient
& cost effective alternative to HVAC for many applications.
Presently there appears to be little interest in adopting any higher DC voltage than 500 – 600 kV in the worldwide market.
Research studies of 800 kV DC system voltage took place as a
cooperation between ABB and the research institute Cepel in Brazil.
[attachment=26136]
INTRODUCTION
A high-voltage, direct current (HVDC) electric power transmission system uses direct current for the bulk transmission of electrical power, in contrast with the more common alternating current systems.
During the latest 20 years, HVDC has become the dominating technology for long distance transmission of bulk power.
The use of 800 kV HVAC that was introduced in several countries during the 1960´s and 1970´s has come to a halt.
The rapid development and the increased confidence in the HVDC technology have caused the transition from ac to dc.
HVAC SYSTEM
Overhead AC transmission is the standard technology for electric power transportation. Traditionally it was preferred over any other transmission technology, especially in rural areas.
No other technology can compete with overhead AC transmission in terms of cost. Technically and economically, overhead AC transmission provides an advantageous solution.
HVDC SYSTEM OVERVIEW
Direct current is put to use in common life for driving our portable
Devices, UPSs, battery systems and vastly in railway locomotives.
If DC is required to be used for transmission & since our
primary source of power is AC the following are the basic steps:
Rectifier (convert AC into DC)
Dc tr. lines (transmit DC)
Inverter (convert DC into AC)
ORIGIN OF HVDC TECHNOLOGY
The first commercially generated electricity by Thomas Alva Edison in the 1880s was DC at low voltage levels.
The AC system by Nikola Tesla made it possible to easily transform
the voltage to higher voltage levels, suitable for transmission of electric
power over long distances.
The development of the mercury arc valves in the 1930s improved the technology and in 1945 a commercial HVDC system in Berlin was commissioned
In 1954 the first commercial HVDC transmission was put into operation with a 96 km sea cable, 20 MW, between the Sweden mainland and the island of Gotland.
CONCLUSION
It is by now clear that HVDC transmission is already a reliable, efficient
& cost effective alternative to HVAC for many applications.
Presently there appears to be little interest in adopting any higher DC voltage than 500 – 600 kV in the worldwide market.
Research studies of 800 kV DC system voltage took place as a
cooperation between ABB and the research institute Cepel in Brazil.