The AC and the DC losses can be equal in the best case but if the AC is degraded then the DC will have less losses than AC. as I said. The reason that AC is used is because of two factors: al generators have more loss than alternators. the commutator has some loss associated. Alternators have no commutator associated with the stator where the power is collected. and transformers are quite efficient in raising or lowering voltage levels. However DC must be level shifted via semiconductor switching components which are not as efficient as a simple transformer then the DC must be inverted to be rendered compatible with our load devices to perform our designated work. The long distance transmission lines must be operated at high voltages to keep current levels down and minimise resistive losses. with ac that is easy and efficiently done with transformers, and with DC we must use inverters and DC/DC voltage reducers which are less efficient and more expensive than the AC transformers. Excuse the lecture but I lectured on AC/DC basics and Industrial Electricity and worked with it for about 50 years...
*Dennis Lee Miles * *Director **E.V.T.I. Inc.* *E-Mail:* *[email protected]* <[email protected]> *Phone #* *(863) 944-9913* Dade City, Florida 33523 USA On Wed, Jun 25, 2014 at 10:32 PM, Robert Bruninga via EV <[email protected]> wrote: > >> "I thought I²R heating was greater for DC. > > > NO, if the power factor is perfect, the losses due to current > > squared times circuit resistance, are... the same for AC and DC, > > I can see that my original statement was confusing. What I meant was that > for the same conductor and same I^2R loss, DC can deliver nearly 40% more > power because the DC line can operate at the PEAK voltage rating of the > line, whereas the AC line only delivers that same current power at RMS > voltage, not peak. 40% increase is worth doing for long point-to-point > transmission (with no taps) > > > On Wed, Jun 25, 2014 at 3:11 PM, Robert Bruninga wrote: > > > > > > > > > [the main] reason we have AC transmission > > > > > is due the difficulties sending DC over long distances. > > > > > > > > But for very long distances, high voltage DC wins. At very long > > > > distances AC is inefficient due to capacitance (and much > > > > shorter when underground/underwater). AC also has additional > > > > Peak vs RMS IsquareR losses. > > > > > > On Wed, Jun 25, 2014 at 12:02 PM, Robert Bruninga wrote: > > > > > Somebody has to pay for road repairs. > > > > > Pipelines are a different issue. > > > > > > > > Rather than spending $billons of dollars on a pipeline monument to > the > > > > past, it is better to make that same investment into electrical > > > > transmission lines for now and the future instead. > > > > > > > > The only thing holding back a near infinite supply of FREE renewable > > > > energy is the lack of the long haul transmission lines to get the > solar > > > > and wind energy from where it is abundant (the plains) to where it is > > > > needed. Pipelines do the same thing for oil but are an ultimate > > > dead-end. > > > > > > > > Anyone want to invest in finding a way to send copper conductors > > through > > > > old pipelines to convert obsolete pipelines to underground DC > > > transmission > > > > lines? > > > > > > > > Bob, Wb4aPR > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140625/bdd13d3f/attachment.htm > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140626/5bec4bf7/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
