![]() ![]() Transformers are used to change the voltage levels in alternating current (AC) transmission circuits, but can't pass DC current. High voltage cannot readily be used for lighting or motors, so transmission-level voltages must be reduced for end-use equipment. While power lost in transmission can also be reduced by decreasing the resistance by increasing the conductor size, larger conductors are heavier and more expensive. Power = ( voltage ) ⋅ ( current ) = ( 2 ⋅ voltage ) ⋅ ( 1 2 ⋅ current ) using half the current at double the voltage reduces the line losses by a factor of 4. ![]() Before the Chinese project of 2019, the longest HVDC link in the world was the Rio Madeira link in Brazil, which consists of two bipoles of ☖00 kV, 3150 MW each, connecting Porto Velho in the state of Rondônia to the São Paulo area with a length of more than 2,500 km (1,600 mi). Early commercial installations included one in the Soviet Union in 1951 between Moscow and Kashira, and a 100 kV, 20 MW system between Gotland and mainland Sweden in 1954. ![]() The modern form of HVDC transmission uses technology developed extensively in the 1930s in Sweden ( ASEA) and in Germany. This improves the stability and economy of each grid, by allowing the exchange of power between previously incompatible networks. HVDC also allows the transfer of power between grid systems running at different frequencies, such as 50 and 60 Hz. Since the power flow through an HVDC link can be controlled independently of the phase angle between source and load, it can stabilize a network against disturbances due to rapid changes in power. HVDC also allows power transmission between AC transmission systems that are not synchronized. HVDC lines are commonly used for long-distance power transmission, since they require less conductor and incur fewer power losses than equivalent AC lines. With this dimension, intercontinental connections become possible which could help to deal with the fluctuations of wind power and photovoltaics. However, a 1,100 kV link in China was completed in 2019 over a distance of 3,300 km (2,100 mi) with a power capacity of 12 GW. Most HVDC links use voltages between 100 kV and 800 kV. Most get their culture fix by interacting with the poncho clad indigenous tribes who reside around the high altitude Lake Titicaca.Electric power transmission system Long distance HVDC lines carrying hydroelectricity from Canada's Nelson River to this converter station where it is converted to AC for use in southern Manitoba's gridĪ high-voltage direct current ( HVDC) electric power transmission system (also called a power superhighway or an electrical superhighway) uses direct current (DC) for electric power transmission, in contrast with the more common alternating current (AC) transmission systems. Beach bums could soak up some rays on the palm tree-fringed playas of Mancora or perhaps enjoy a unique aquatic experience at the lush desert oasis of Huacachina. Serious alpine enthusiasts, however, would rather relish in the hills around the hiking hub of Huaraz, which boasts some of the most jaw-dropping high altitude trails in the world. The colonial gem of Arequipa showcases the country’s finest old-world architecture, while the nearby condor filled Colca Canyon is a true trekker’s delight. Just outside town, the lush rolling hills of the sacred valley are bursting with exotic Inca sites to explore. The ancient Inca enclave and colonial capital of Cusco attracts hordes of travelers for its elegant Renaissance architecture that’s framed by a backdrop of imposing snow-capped peaks. The most memorable way to experience this ancient wonder is by hiking the Inca Trail, a demanding three-day trek that ascends to dizzying heights. ![]() The obvious bucket-list attraction is Machu Picchu, a magnificent Inca citadel that’s perched precariously atop dramatic Andean mountain peaks. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |