The reason we use AC is that the AC voltage is easily changed using a transformer. To change DC voltage requires complex and inefficient circuitry. So if we increase the supply voltage V we decrease the power lost. This is why the electricity transmission lines use very high voltages.
Why are transmission lines AC instead of DC?
Advantages of AC Transmission System
AC Circuit breakers are cheaper than DC Circuit breakers. The repairing and maintenance of the AC sub station is easier and inexpensive than DC Substation. The Level of AC voltage may be increased or decreased by using step up and Step down transformers.
Why is AC preferred 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.
Are transmission lines DC or AC?
Transmission lines mostly use high-voltage AC (alternating current), but an important class of transmission line uses high voltage direct current. The voltage level is changed with transformers, stepping up the voltage for transmission, then reducing voltage for local distribution and then use by customers.
Why DC is not used in transmission?
DC(Direct Current) is not used over AC(Alternating Current) in transmission because DC goes heavy attenuation while transmission over long distance as we do not transform it from Low Voltage (at which it is being generated) to High voltage (for transmission over long distance(I will explain…)) by some direct mean …
Is corona more in DC lines or AC lines?
Detailed Solution. The corona losses in transmission line Pc is proportional frequency, i.e. Hence, P c a c > P c d c or corona losses for standard AC transmission are greater than DC transmission. We can also say that corona losses in DC transmission are minimum.
Why power loss is less in AC?
The main advantage of AC for power distribution is the ability to step up to high voltages which does reduce power losses (I=P/V) (P= I^2 R). rcgldr said: The main advantage of AC for power distribution is the ability to step up to high voltages which does reduce power losses (P= I^2 R).
Why is AC safer than 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. The frequency of 60 cycles is in an extremely harmful range. At this frequency, even a small voltage of 25 volts can kill a person.
Why can’t DC travel long distances?
The main reason is that the Skin effect in AC systems increase the conductor size. However, in DC, the conductor requirement is lower as there is no skin effect. This reduces the conductor cost.
What is the disadvantage of air conditioner?
Spending increased amount of time in an air-conditioned room can make your skin lose its moisture, thereby becoming sensitive and dry. It can also cause irritation and dryness of the mucous membrane. A sudden change in temperature has shown to exacerbate the symptoms of various respiratory diseases.
What is AC transmission line?
The AC transmission line is used for transmitting the bulk of the power generation end to the consumer end. The power is generated in the generating station. The transmission line transmits the power from generation to the consumer end.
Why AC has less loss than DC?
DC is more efficient than AC power and has lower line losses than AC lines. With AC, the current travels on the skin of the conductor while with DC, the current flows throughout the entire conductor and not just the conductor skin. DC therefore has lower skin losses in the line.
Why are submarine cables DC?
The advantage of AC over DC is that in AC transformers can be used to step up or down the voltage level. DC current is however more suitable for bulk transmission over long distances than AC where the losses are higher.
What is corona loss in transmission line?
Corona appears in the transmission line when the surface voltage gradient at the line conductor reaches the breakdown stress. Due to corona, heat and bluish light produce. There is a loss of power and energy dissipation. This loss is known as the corona loss.
Why is DC underwater?
The early undersea cables used high voltage DC because you can use thinner insulation for DC than for AC and the cables were already very thick, heavy and unwieldy to lay from a ship. Not sure what today’s technology brings to that problem.