AC Biased

Discussion in 'Feedback and Suggestions' started by Unregistered, Aug 5, 2009.

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In "Volume 2 AC-Basic AC Theory-What is alternating current (AC)?" it is stated, "...AC an advantage unmatched by DC in the realm of power distribution...". Are the authors aware that high voltage DC is commonly used for long range power transmission? Furthermore, it is stated in the text "When transmitting electical power over long distances, it is far more efficient to do so with stepped-up voltages...". Is there any way confusion may be minimized by removing the pollution of mystical fabricated terms like "stepped-up voltage" for this explanation? Could the words "stepped-up voltage" simply be replaced with the words "high voltage"? I believe emphasis should be placed on the fact that, high voltage is what makes long range power transmission possible. Please continue the fight of ingorance you have demonstrated with the very publication of this text by not creating an illusion that leads students to believe that somehow losses can be elimated by the periodical reversal of current.

2. t_n_k AAC Fanatic!

Mar 6, 2009
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It's a pity 'guest' didn't join the forum and explore a more satisfactory discussion of this interesting topic. It would be enlightening for me and (presumably) many others as to the trade-offs and technology advantages / limitations that dictate a practical (economic, etc.) choice between HVDC and HVAC transmission systems.

3. KL7AJ AAC Fanatic!

Nov 4, 2008
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High voltage DC power transmission has some advantages, but its current status in the U.S., at least, is "not ready for prime time".

1)For a given effective voltage, DC has lower insulation requirements...you only have to withstand the DC voltage, not the peak voltage. Corona effects are SLIGHTLY reduced.

2)Radiation losses over long distances are reduced

Disadvantages: Any step up or step down process required re-inversion to AC, with its attendant losses

Inverting devices (triacs, SCR's etc.) for the extreme high voltages used in HVDC are still VERY exotic and expensive devices. This technology must still be considered somewhat experimental at this time.

Hope this helps.

Eric