Power DesignLine Blog
AC versus DC power distribution: the pendulum swings
Bill Schweber
4/10/2010 12:00 PM EDT
But a press release on a report from The Darnell Group caught my attention. It discusses the continued growth of DC power distribution in buildings, and what's driving the trend; LED-based lighting, was cited as one major driver.
The AC vs. DC battle has "raged" since Edison promoted DC power while Charles Steinmetz (and General Electric) felt that AC was the way to go. As we know, AC won the battle, since it was so much easier to step up and step down via transformers, and higher voltages greatly reduce resistive (IR) loss; (see my recent column on this, "Is this something for (almost) nothing?".
But high-voltage DC has some advantages over AC, as long as you can do the step-up and step-down efficiently, which we now can do with advanced DC/AC converters and AC/DC rectifiers; there are DC lines in use now running at 100s of kV. In short: new technologies have both changed what we can do (high-voltage DC), and what we want to do (DC distribution to match new loads). The increased availability of DC distribution may be a development to keep in mind. Meanwhile, think about what the architectural impact availability of higher-voltage DC rails will mean for your power-distribution and conversion topologies. The law of unintended consequences can be your friend or your foe!♦
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Amcfarl
4/22/2010 7:23 AM EDT
Nice idea but 50KHz would increase skin and proximity effect losses to unacceptable levels. Plus all rectifying would then have to employ ultra-fast rectifiers, meaning that most input rectifier stages presnetly in existence would then be unusable
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rosekcmr
4/22/2010 1:23 PM EDT
This is referring to BIG power distribution; Megawatts up to 800kV extended over thousands of km. Besides that, the cost of distributing 50kHz power over twisted pair shielded wire would be cost prohibitive. HVDC can (and is) also be buried on land or on sea beds. China and India all have projects in the works to implement HVDC distribution over their vast continents. Once again, the US could be saddled with obsolete, legacy technology - he who has the best tools wins!
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