AC vs DC Industrial Power Generation
AC vs DC Industrial Power Generation
(OP)
Can anyone point me in the direction of any authoritative articles on the relative efficiency of current industrial AC vs DC power generation?
Thanks
Thanks
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
AC vs DC Industrial Power Generation
|
RE: AC vs DC Industrial Power Generation
Dc motors were at one time controlled by motor generator sets generating DC but most are now driven and controlled by controllers that input and rectify AC. Even DC motors are being phased out in favour of VFD controlled AC motors. DC was once commercially available in large cities with trolly systems. It was used in major buildings for driving DC elevator motors. Most of these DC services were phased out around 50 years ago.
There is virtually no DC generation left. The number of applications where DC has been replaced by AC should give you a good overview of the relative overall efficiency and usability of AC versus DC.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: AC vs DC Industrial Power Generation
You didn't ask about transmission systems, but I'll mention that dc has a number of advantages for transmission systems. Here are some things that spring to mind:
1 - It can be used to transfer power between separate ac grids which are not synchronized to each other
2 - Does not have the same stability-related limitations as ac related to transmitting real power through inductive paths.
3 - less or no skin effect means conductors can be smaller or cheaper or lighter. Also perhaps the transmitted current is slightly less because there are no vars (sudes?) to transport around
4 - Managing real power flow is simpler.
5 - Through control of power on dc systems, a certain small degree of improved indirect control is achieved for the ac systems that they connect to.
Note dc used to be at a big disadvantage due to higher cost of power electronics compared to transformers. The cost of electronics tends to decrease over time but cost of transformers does not.
Disclaimer: I am not an authoritative refernce (I think you figured that out). If you have interest in benefits of dc on transmission side you might ask on the power forum.
=====================================
(2B)+(2B)' ?
RE: AC vs DC Industrial Power Generation
But that said, it will also depend on the INDUSTRY you are talking about. If the preponderance of end use machinery or process uses DC, then it might make sense.
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: AC vs DC Industrial Power Generation
Hence my first line: "You didn't ask about transmission systems, but..."
=====================================
(2B)+(2B)' ?
RE: AC vs DC Industrial Power Generation
Anyone have any thoughts on that?
RE: AC vs DC Industrial Power Generation
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: AC vs DC Industrial Power Generation
Adding to what have benn said before.. AC can be polyphase. AC machinery can grow much bigger than DC. This makes concentrated power generation cheaper.
"If an experiment works, something has gone wrong"
RE: AC vs DC Industrial Power Generation
RE: AC vs DC Industrial Power Generation
The development of high voltage/high power semiconductor devices is making the difference.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: AC vs DC Industrial Power Generation
in particular the Insulated Gate Bipolar Transistor... Today's hybrid drive vehicles, super high efficiency UPS systems, mag-lev trains would not be possible without it..
http://www.ece.ncsu.edu/people/bjbaliga
http://people.engr.ncsu.edu/bjbaliga/IGBT_Applicat...
RE: AC vs DC Industrial Power Generation
I didn't know you had been in the business long enough to remember the transition from Edison to Westinghouse.
I can only add to this discussion that in my 30 years of wandering around industrial plants, I've only run into one DC system, which was at a giant chromium smelting plant.
Best to you,
Goober Dave
Haven't see the forum policies? Do so now: Forum Policies
RE: AC vs DC Industrial Power Generation
Third rail systems generally use 600 or 750V, however the BART system in The Bay Area of California uses third rail at 1000V. The Hamburg S-Bahn uses 1200V side-contact third rail.
All modern systems are supplied from Silicon rectifier substations. Gone are the mercury arc, synchronous converters, and MG sets of former decades. But some are still around, here and there.
rasevskii
RE: AC vs DC Industrial Power Generation