Applications
Posted JUN 21 2015 by LEANDRO and VINICIUS.
BRASIL
Rio Madeira:
The world’s longest power transmission link
Recently commissioned the Rio Madeira high-voltage direct current (HVDC) link in Brazil, which will transmit 3,150 megawatts of electricity across 2,400 kilometers. Brazil is the fifth largest country in the world and covers an area equivalent to around 80% of Europe. Size here takes on a different meaning, so it’s fitting that the country is home to Rio Madeira, the world’s longest HVDC link, connecting remote energy generation sources in the northwest to large electrical consumption centers around São Paulo, Brazil's main economic center, around 2,400 kilometers to the south east.
ABB successfully commissioned the HVDC converter stations to the link and delivered the project to global company Abengoa in August 2014. The link brings electricity from two hydropower plants in the northwest of the country, which harbors about 70 percent of Brazil’s more than 100,000 megawatts (MW) of potential hydropower generation. .
The HDVC technological viability: Transformers
Seven HDVC transformers with a power capacity of 600kv are between the main components that are going to regulate the energy flow and raise the efficiency and confiability of electricity transmitted to the long distance consumers. Each transformer weight around 400 tons, making them the biggest transformers ever built.
However, before arriving in the facility, they had to travel from Ludvika (Sweden) crossing the Atlantic Ocean and then Rio Madeira River until its final destination Porto Velho, Brazil. This long trip across ocean, cities, villages, railroads, streets and ships had a planning and logistics deeply detailed. The first part of the trip were made by railroads and transported the equipment from Ludvika to the Sweden harbor of Oxelosund, where it was loaded into a ship and then set sail to the Brazilian city of Manaus. This Atlantic journey took 20 days.
At Manaus, each transformer was carefully placed in a great ship to continue travelling until Rio Madeira, Porto Velho. Because of the transformers weight, the river should be 7 meters deep at least. They had to wait until autumn to continue navigating. From Porto Velho to its final destination, it would be a journey of 20 kilometers. In this final stage, the transformers were loaded into an enormous semi-trailer driven by 5 trucks. The journey ended when the transformers finally reached the substation.
Biggest HDVC power grid in the world, with 2400 kilometers. It will transmit 3.150 megawatts form Porto Velho to Araraquara. A curious fact is that each transformer weights around 400 tons, making them the biggest transformers ever made.
Itaipu
One of the largest HVDC transmissions in the world - two major ABB HVDC links that supply Sao Paulo
Itaipu is one of the largest HVDC overhead line transmission projects in the world, and one of two major ABB-built HVDC links built to supply the industrial southeastern region of São Paulo with power. Owned by Furnas Centrais Elétricas in Rio de Janeiro (an Elétrobras company), the Itaipu HVDC Transmission project has a total rated power of 6,300 MW and voltage of ±600 kV, delivering power from the 12,600 MW Itaipu hydroelectric power plant.
The Itaipu HVDC transmission consists of two ±600 kV bipoles, each with a rated power of 3,150 MW, delivering power generated at 50 Hz from the Paraguay side of the Itaipu Dam (near Foz do Iguaçu in Paraná) to the 60 Hz network in São Paulo via the Ibiúna converter station.
For more than 20 years, Itaipu was the largest and most powerful HVDC transmission in the world. It was supplanted in 2010 when the 6,400 MW ±800 kV Xiangjiaba-Shanghai UHVDC transmission system went into commercial operation. Itaipu transmission began on bipole 1 in October 1984 with 300 kV, and in July 1985 with 600 kV, and on bipole 2 in July 1990.
HVDC was chosen partly to supply power from the 50 Hz generators to the 60 Hz system, and partly because an HVDC link was economically preferable given the long distance involved. The converter stations Foz do Iguaçu and Ibiuna represented a considerable step forward in HVDC technology compared to the HVDC stations of the 1970s. The two stations are still unique in their combination of size and advanced technology.
GARABI: Brazil-Argentina HVDC Interconnection
The Argentina - Brazil HVDC interconnection, owned by Cien/Endesa Group, demonstrates the advantages of the modular HVDC back-to-back interconnection concept in a project designed to encourage cross-border energy trading between the two countries.
The transmission system comprises 490 km of 500 kV AC overhead lines between the two substations of Rincón de Santa Maria in northern Argentina and Itá in southern Brazil, and an HVDC converter station at Garabi in Brazil, near the border.
Argentina's power system operates at 50 Hz, and Brazil's operates at 60 Hz. The asynchronous interconnection is through HVDC frequency converters in a back-to-back configuration at Garabi.
ABB's capacitor commutated converter (CCC)-type HVDC converter technology made it possible to avoid building a synchronous compensator plant at Garabi. Each of the two 1,100 MW phases of the Garabi back-to-back station is divided into two blocks of 550 MW each. The first phase went into commercial operation in 1999, the second phase in 2002.
A CCC/ConTune combination in the converters enables secure operation at low short circuit levels, improving reactive power control and providing even and continuous voltage and power flow control. The converter station's modular construction concept simplifies civil design and ensures an environmentally acceptable solution and shorter delivery time.
Each line from Garabi to Itá in Brazil is 354 km long, a challenge for a converter station that guarantees delivery of 1,000 MW into a rather weak point of the grid.
This cross-border system enables both countries to utilize electricity resources more efficiently and cost-effectively, increasing system reliability and enabling secondary energy trades. The time schedule for completion of the first phase was only 22 months, a significant challenge for a project of this magnitude.
Main data
Commissioning year: Second phase 2002 First phase 1999
Power rating: 2,200 MW
No. of circuits: 4
AC voltage: 500 kV (both sides)
DC voltage: ± 70 kV
Type of link: Back-to-back station with CCC
Main reason for choosing HVDC: Asynchronous link between a 50 Hz and a 60 Hz system
Application: Interconnecting grids
WORLD
HVDC Gotland
The HDVC that links the island of Gotland at Sweden’s east coast are notable, historically. The first was, actually, requested in 1954, making it the very first HVDC power grid in the world. It was built by ASEA. It linked the city of Vastervik with Visby.
Gotland HVDC Light
In 1999, the island of Gotland is, again, a pioneer at HVDC field as the first commercial tension grid, called VSC, is built by ABB. Tis link connects the north and the south of the island. This must be used to allow the discharge of electrical energy produced by windy turbines from the south of the island to the continent. This is a symmetrical monopole.
Pacific Intertie
The Pacific Intertie was the first major HVDC link in the US, and has undergone major expansions and refurbishment and ABB has been heavily involved over the years.
In 1965, ABB and General Electric were awarded a contract for a 1,440 MW, ± 400 kV transmission system - a challenge at the time since the line voltage, length and current were greater than any HVDC project built. The system was operating in 1970, until an earthquake devastated the Sylmar converter station, near Los Angeles. Operation was restored by 1973. A few years later, the owners raised the transmission rating to 2,000 A and 1,600 MW, the equipment`s inherent capacity.
Pacific Intertie upgrade
Increasing power demand as older generation around Los Angeles was retired led operators to upgrade capacity on the Pacific Intertie transmission by raising line voltage resulting in a total capacity of 2,000 MW. The Pacific Intertie upgrade (PIU) was commissioned by ABB in 1985.
Pacific Intertie expansion
In 1985, ABB was contracted to extend the Pacific Intertie transmission to 3,100 MW - the Pacific Intertie expansion (PIE). New 1,100 MW converter stations were installed in parallel with existing stations, and current in the DC line rose to 3,100 A. The PIE was commissioned in 1989.
Sylmar converter station
Damaged in a 1994 earthquake, the Sylmar converter station`s original mercury-arc valves were also nearing the end of their design life, so the owners LADWP built a new 500 kV, 3,100 MW converter station at the existing facility. The existing converters and control building were modified, and the valve halls and as much existing equipment as possible reused. The new station went into service in 2004.
Celilo station upgrade
In 2013, to secure the reliability of this major power supply, Bonneville Power Administration, the owners of the Celilo northern station, decided to make a refurbish and upgrade station capacity to 3,800 MW. ABB will commission the upgraded station in 2016.
Cahora Bassa
The Cahora Bassa HVDC transmission system is an important source of imported power for the South African grid.
The link provides 1,920 MW of power transmission capacity from a hydropower plant on the Zambezi River in northern Mozambique, and was put into service in three stages, from 1977 to 1979.
The HVDC system includes the Songo converter station in Mozambique near the Cahora Bassa hydropower plant, and the Apollo converter station in South Africa near Johannesburg, which were built by the ZAMCO consortium (AEG-Telefunken, Brown Boveri Company (BBC) and Siemens). The power link is owned by the power utilities, Hidroeléctrica De Cahora Bassa (HCB) in Mozambique and Eskom in South Africa. The system comprises two parallel monopolar lines across a 1,400-km long route; 900 km is in Mozambican territory.
The Apollo station upgrade
In 2006, Eskom awarded ABB a contract to upgrade the Apollo converter station in South Africa to boost its transmission capacity from 1,920 MW to 2,500 MW now, and prepare it for a future upgrade to 3,960 MW. The upgrade significantly increases the station's power availability and reliability, and reduces required maintenance.
ABB’s unique air-insulated outdoor thyristor valves replaced the old oil-insulated valves and were mounted on the existing support insulators. This produced significant savings, since it required only minimal changes to the station's physical arrangement. The upgrade was completed quickly with minimal transmission disruption.
The Songo station refurbishment
In 2012, HCB awarded ABB a contract to replace key high-voltage equipment, such as transformers, DC smoothing reactors, arresters and measuring equipment at the northern converter station, Songo in Mozambique. The refurbishment enhances power availability and improves system reliability. Commissioning will take place in two parts - DC equipment in 2013, transformers in 2014.