What iare the main advantages of Dc power supply transmission over AC transmission?

Question

In High voltage power transmission what are the special feature and advantages of DC over Ac ?.What is the maximum kv dc can be transmitted ?what is % of power loss reduced in DC ?.Brief me how high voltage Dc inverted to AC with power thyristers? or other power electronics? & its relaiability , I need brief details

Answer 1

From what I could glimpse of the answers so far, nobody (edit: except ernie) really has hit on the major advantage of DC transmission, and it appears that some believe that DC is never used (on the contrary, the Pacific Intertie that connects the Pacific Northwest with south California is but one of a few examples worldwide).

While you probably already know the various advantages of 3phase AC transmission (usable by transformers, naturally created by generators, etc), the one primary advantage that DC has over AC is the number of conductors (and hence cost to implement).

There is a point where the length of a set of AC transmission lines dictates that it would be cheaper to implement under DC using AC/DC conversion and the fewer lines. Other advantages include very little line reactance or skin effect, which both reduce the line impedance. Obviously, the length where DC is more economical than AC is pretty long, otherwise you would see it more often.

Max voltage at which DC can be transmitted? That I am not too sure. It could be the limit in the rectifier/inverter technology or it could be the limit in the insulator technology, or it could even be the corona losses become too high at some point. I do know that DC transmission operates pretty much exclusively as a bulk transmission connection between two distant points at high voltages.

% power loss reduced in DC? I couldn't really give you an estimate, but I know it will probably depend on quite a few factors.

How high DC voltage inverted to AC & reliability? This I am not sure of the specifics, but I would assume it is reliable enough since large interties between remote places depend on that long range DC link to function.

I hope that is brief enough. Maybe a web search will pull up some examples of voltages at which these operate.

Answer 2

The advantages of DC over AC is it can carry more power per conductor. Also during long distances where there is an enormous amount of capacitance in the line. As we well know, DC tends to ignore capacitance other than to charge it up where as AC will pass through a capacitor or act as if it does, resulting in power loss.
DC voltage does not have a corona discharge as does AC. That is to say AC is leaking out everywhere. 800,000 volts seems to be the top end for DC,and is about the breakdown voltage for the semiconductors used to convert it to AC. Although you can place these components in series so that each semiconductor has a share of the total amount of voltage.
Now the percentage question. 80% more power could be transmitted using DC, and is inverted to AC using a static inverter.

Answer 3

The only good thing in power transmission about DC is that it can be stored.
It cannot be converted to AC with inverters over a few thousand volts without being very costly. It could probably be transmitted at the same voltage as AC but there is no cheap way such as a transformer to get it back down to a usable voltage. Solid state inverters cannot operate at transmission voltages (yet).
High voltage rotating motor generators would be the only way to shift voltage levels but they are limited to below necessary transmission levels (this is a step backwards).
The power loss will be the same as AC for any given voltage and current.

Answer 4

If you transmit in DC you will have I*I*R losses (resistive losses) that are pretty significant. If you chance upon the brilliant idea of transmitting high-voltage DC (for the same given power, thus lesser current transmitted), you need to generate DC at a very high voltage (remember - voltage-transformers are for AC). That is exceedingly expensive compared with a similar sized AC generator. AC on the other hand can ge generated at any voltage level, stepped up thru transformers appropriately (hv transmission minimizes the line losses), and transmitted effectvely. There are a few DC transmission links that exist (notably in the US, between Chief Joseph and California). Here AC is rectified using power devices and transmitted over high-voltage DC links, and inverted at the receiving end.

One of the main advantages of DC links is stability of power transmission. They isolate two areas from inter-area power oscillations which is all too frequent in large interconnected ac systems.

Answer 5

Mike's answer gives you the technical info. There is, however, an even more important advantage/disadvantage priority. Cost. The mains supply is created using simple mechanisms to convert natural (usually) forces into electrical power. The cheapest is using an AC generator as they have a simpler construction and are cheaper to make. The work horse used by the public and industry is the motor. The different types are various but in comparison to the DC equivalent are, on the whole, simpler mechanically. As Mike says: DC motors have a more reliable operation and are easier to control. With a dirt cheap AC motor you can also emulate the DC operational equivalent using an inverter, which is now relatively cheap. The main disadvantage with AC, though, is having the ability to store it. DC can be topped up into batteries. What the AC equivalent is, I am unsure. Industrially everything comes down to economics.

Answer 6

IR loss is the key. It's minmized with AC by starting out at the source with a very high voltage and minimum current - it is easily converted to 240/120 at the pole transformers for household use. DC, on the other hand, suffers the same IR loss without the benefit of cranking out a huge voltage and then easily converting it to a usable amount for consumer use. DC at the plug would sure simplify the power supplies in today's modern electronic devices. And any benefits would be lost with DC if you intend to convert it to AC when it gets to the end user. (FYI: Edison was a firm believer in DC transmission - only to find AC transmission winning out due simply to economics.)

Answer 7

Advantages Of Power Supply

Answer 8

DC current doesn't travel as well as AC.
That's why you have AC power in your home and DC power for your car. Nothing is very far from the battery.
All high voltage lines are AC.
AC is converted to DC in radios, TVs and other plug in electronics.

Answer 9

There is none.You will incur a lot of losses if you transmit in DC and will heat up your cables and very expensive too.That is the reason why AC transmission is preferred over DC transmission.

Answer 10

For the best answers, search on this site https://shorturl.im/axsIm

Constant speed: AC Variable speed: DC .