# Which current is used for long distance transmission

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Most transmission lines are high-voltage three-phase alternating current (AC), although single phase AC is sometimes used in railway electrification systems. High-voltage direct-current (HVDC) technology is used for greater efficiency over very long distances (typically hundreds of miles).

## Is AC or DC better for long distance transmission?

Alternating current is cheaper to generate and has fewer energy losses than direct current when transmitting electricity over long distances. Although for very long distances (more than 1000 km), direct current can often be better.

## Why AC current is used for long distance transmission?

AC is still preferred for general distribution because it is much easier to transform the voltage up or down. High voltage is preferred for long distance transmission because there is less current at high voltage for the same power. There are lower loses in the transmission lines due to lower current.

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## Why DC current is not used for transmission?

Why DC is not used for transmission

When the voltage is stepped up the current will be reduced so the conductor size can be reduced and the cost is reduced. The voltage drop is reduced so long-distance transmission is possible.

## Which metal is used as long distance transmission of electricity?

An aluminium wire have a 1.5 times larger cross section to pass the same current as a copper wire, but two times lighter. Weight is one of the most important parameters for high-voltage power lines that transmit power over long distances. Therefore, only aluminium wires are used in main overhead power lines.

## Why is AC preferred over DC for long distance transmission?

Answer: Ac is more preferred than dc because it is easy to maintain and change the voltage of ac for transmission and distribution purpose. Plant cost of ac transmission is much lower compared to dc transimission. When fault occurs it is easy to interrupt ac supply.

## Which is more dangerous AC or DC?

Alternating current (A.C) is five times more dangerous than Direct current (D.C). The frequency of the alternating current is the main reason for this severe effect on the human body. … At this frequency, even a small voltage of 25 volts can kill a person.

## Does AC or DC travel further?

Alternating Current (AC) does not travel further than Direct Current (DC), in fact DC does a little better with less loss for the same voltage. The difference is that AC can be easily stepped up and down with transformers. This is harder to do, electronically, with DC but can now be done.

## Why AC is more dangerous than DC?

A.C. is said to be four to five times more dangerous than D.C. For one thing, A.C. causes more severe muscular contractions. For another, it stimulates sweating, which lowers the skin resistance. … The frequency of the AC has a lot to do with the effect on the human body.

## Why do we prefer AC over DC?

One of the biggest advantages of AC over DC is that it is relatively cheap to change the voltage of any current. It is also best suited for transporting electrical current over long distances when compared to DC, as energy losses are considerably reduced.

## Can DC power kill you?

The current may, if it is high enough and is delivered at sufficient voltage, cause tissue damage or fibrillation which can cause cardiac arrest; more than 30 mA of AC (rms, 60 Hz) or 300 – 500 mA of DC at high voltage can cause fibrillation.

## Are transmission lines AC or DC?

Most transmission lines are high-voltage three-phase alternating current (AC), although single phase AC is sometimes used in railway electrification systems. High-voltage direct-current (HVDC) technology is used for greater efficiency over very long distances (typically hundreds of miles).

## How far can DC power be transmitted?

The DC transmission line may be very short in a back-to-back link, or extend hundreds of miles (km) overhead, underground or underwater. One conductor of the DC line may be replaced by connections to earth ground.

## Why cables are not used for long distance transmission?

Long-distance, electric-power, transmission lines always operate at very high voltage, sometimes as much as 750 kV. … To deal with this, the insulation for the high voltage cable needs to be very specialized and is prone to breaking down due to the voltage tunneling its way through the insulation.

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## Why are copper and Aluminium usually used for electricity transmission?

The resistivity of copper and aluminium are very low, so electric current flows easily through them. Hence copper and aluminum wires are usually used for electricity transmission.

## Why are Galvanised steel conductors not suitable for transmitting large power over long distance?

The tensile strength of Steel is very high, therefore it can be used for power transmission for long distance where the chance of mechanical loading is quite high. But because of its poor conductivity and high resistance, Galvanized Steel is not used for power transmission over a long distance.