Re: [tlug] OT: DC Power Transmission can be more efficient

[jep200404 <jep200404@example.com>]

"SL Baur" wrote:

> DC power transmission has always been lossier and thus more
> expensive to deliver than AC. 

Things have changed. 

Where the lines are long, now DC tranmission lines are often more 
efficient and practical that AC ones. 

   http://en.wikipedia.org/wiki/High-voltage_direct_current#Advantages_of_HVDC_over_AC_transmission
   http://en.wikipedia.org/wiki/List_of_HVDC_projects

By the way, there can be reasons other than efficiency for using 
DC power tranmission. DC can be used to bridge unsynchronized 
AC systems, such as between Japan's 50 Hz and 60 Hz AC systems. 

---

I remember when computers had big honkin' power supplies 
with a big (possibly ferro-resonant) transformer, big diodes, 
big capacitors, and big heat sinks on linear regulators. 
They were big, heavy, and inefficient. Switching power supplies 
were uncommon. The closest most folks got to switchers was the 
vibrator thing for tube radios in cars. 

Now, the vast majority of computers (including those running 
Linux) have switching power supplies. Laptops usually have 
several (switching) DC to DC converters inside. 
Even many wall warts have switching power supplies now. 

Of course the same technology behind the switching power 
supplies, is scaled up for DC power transmission. 

Nonetheless, I tip my hat to Tesla.