To contact us Click HERE
This breakthrough combined with the superconducting cable nowavailable not only allows power to be accumulated but allows hugeamounts of power to be routinely shifted coast to coast when optimal.
It was not apparent to me before, but such a system lives wellunderground eliminating a host of problems and vulnerabilities.
We will evolve to a grid that is almost untouchable to even naturaldisaster. More critically the bulk of line loss will now disappearexcept that close to the customer and even that is again a legacyissue that can be optimized. We do prefer AC in the home and areasof heavy human traffic. What is needed is super efficient rectifiersclose by because buried cables can bring DC safely into theneighborhood.
This will mean a huge increase in power availability without buildingnew capacity.
ABB Advance MakesRenewable-Energy Supergrids Practical
A high-power circuitbreaker makes it possible to create highly efficient DC power grids.
November 12, 2012
ABB, the large powerand automation company, has developed technology that could providean efficient way to transmit power from widely distributed solarpanels, wind turbines, and other sources of renewable energy. The newtechnology is a fast and efficient circuit breaker forhigh-voltage direct-current (DC) power lines, a device that haseluded technologists for 100 years. The breaker makes it possible tojoin high-voltage DC transmission lines to form a resilient powergrid.
If renewable energy isever to account for a large part of the total energy supply,countries will need to install new, large-scale transmission grids,both to get power to cities from remote areas such as deserts thatoften have the best renewable resources, and to combine power fromwidely distributed wind turbines and solar panels, which can helpaverage out fluctuations in their output. In Europe, there's beentalk for years of a supergrid that would pull together power fromhydroelectric dams in Scandinavia with wind farms in Germany andlarge solar farms in Spain and even North Africa (see “A Supergridfor Europe”).
But such a supergridhas faced serious technical hurdles. The transmission lines that makeup conventional power grids use alternating current (AC), which loseslarge amounts of power over long distances unless complicated andexpensive measures are taken. DC is more efficient over longdistances, and it offers the additional benefit of working wellunderground and underwater, reducing or eliminating the need for theunsightly transmission towers that can make it difficult to site newtransmission lines.
DC lines have longbeen used to transmit power across the North Sea, and from largehydroelectric dams to cities. But until ABB's advance, it wasn't safeto connect DC lines into a large-scale grid.ABB's circuit breakerchanges that. Within five milliseconds it can stop the flow of a hugeamount of power—equal to the entire output of a nuclear powerplant, ABB says. The breakers could be used to nearly instantaneouslyreroute power in a DC grid around a problem, allowing the grid tokeep functioning. “Ordinarily, if something goes wrong anywhere,all the power goes off,” says Claes Rytoft, ABB’s chieftechnology officer. “The breaker can cut out the faulty line andkeep the rest healthy.”
Researchers have beentrying to develop high-voltage DC circuit breakers for a century (see“Edison’s Revenge: The Rise of DC Power”). Mechanical switchesalone didn't work—they shut off power too slowly. Power electronicsmade of transistors that can switch on and off large amounts of poweroffered a possible solution, but they proved far too inefficient.ABB's solution combines power electronics with a mechanical switch tocreate a hybrid system that's both fast and efficient. The newcircuit breaker could also be far less expensive than systems thatuse only transistors.
“The cost of thepower electronics breaker was humongous,” says Ram Adapa, a powerdelivery technical leader at the Electric Power Research Institute.“The hybrid breaker should be less costly.”With the major hurdleto DC grids out of the way, ABB is now developing algorithms tocontrol them. The system will still need to work in concert with AClines for distributing the power in local communities, since there isno inexpensive DC equivalent of the transformers needed to step downpower to the relatively low voltages used in homes and businesses.One of the first markets for the new technology could be Germany,which has decided to turn off its nuclear power plants and relyheavily on renewable energy (see “The Great German EnergyExperiment”).
The degree to whichhigh-voltage DC grids can help renewables may depend on the economicsof installing underground cables versus overhead lines. Obtainingrights-of-way is one of the biggest obstacles to installing newtransmission lines in many countries, and underground installationsdon’t require obtaining new rights-of-way, since they can be easilyinstalled along existing roadways. ABB says that when the entiresystem cost is taken into account, underground installations are onlyslightly more expensive than overhead ones. But Adapa is skeptical,saying that underground installations could cost five times as much.
Hiç yorum yok:
Yorum Gönder