10 Advantages of Alternating Current over Direct Current

This article describes the advantages of AC over DC. The alternating current is known as AC and the direct current is known as DC.

Alternating current(AC) is widely used for domestic and industrial applications. AC is used in many applications, including power transmission, motors, heating & cooling, welding, and lighting. Direct current (DC) is used for applications like battery chargers, DC motors, electroplating, welding, and electronics. Thus, both AC and DC are important for specific applications.

Both AC and DC have advantages and disadvantages when compared to each other. In this article, we will confine our discussion to the advantages of AC over DC. Let us first know what are the Alternating Current(AC) and direct current(DC).

Alternating current – Basic Definition

The alter means ” to change something”. Alternating current means the current that reverses its polarity after a certain time. If the change in the polarity is after a specific time, it is called periodic AC, and if the polarity changes arbitrarily after any time period, an AC waveform is called a non-periodic waveform. The periodic AC waveform is shown in the below picture.

Advantages of AC over DC

You may see that the AC changes its polarity after every 10 milliseconds if the frequency of AC is 50 Hz. If the frequency is 60 Hz, the AC changes its polarity after 8.33 milliseconds. The symbol of AC is shown in the below picture.

symbol of AC

Thus we can say, an AC (alternating current) is a type of electrical current that reverses its direction periodically with constantly changing its magnitude and polarity.

Direct current – Basic Definition

Contrary to AC, DC (direct current) does not change its direction and magnitude. Thus, DC is a type of electrical current of constant magnitude and polarity that flows in one direction only. The DC waveform is shown in the below picture.

advantages of ac over dc

Thus we can say, DC (direct current) is a type of electrical current that has constant magnitude and it does not change the polarity and flows in one direction only. The symbol of DC is given in the below picture.

DC-direct current symbol

Now, we will discuss the advantages of AC over DC.

Advantages of AC over DC

The followings are the advantages of AC over DC.

  1. Easy Voltage Transformation: AC can be easily changed to different voltage levels using transformers. The transformers can efficiently do the stepping up or stepping down voltage for transmission, distribution, and utilization. On the other hand, DC requires a converter and inverter circuit to achieve voltage transformation. The converter and inverter make the voltage transformation system very intricate. Thus, voltage transformation is one of the major advantages of AC over DC.
  2. Easy Power Generation: Ac alternators or synchronous AC generators (alternators) are used to generate AC. The advantage of AC is that alternators are simple in construction, more reliable in operation, and less expensive compared to DC generators. Alternators can be directly connected to the power grid, on the other hand, DC generators need additional equipment like inverters and converters for power conversion. Also, the power conversion cause harmonics in the electrical network.
  3. More Suitable Power Distribution: Most of the electrical equipment operates on AC. The advantage of AC over DC is that it can be easily distributed for AC-operated equipment across a grid using an overhead transmission line and underground cables. Whereas, DC power distribution requires complex and expensive conversion systems.
  4. Easy Conversion of AC into DC: One more advantage of AC over DC is that the AC voltage can be easily converted into DC using rectifiers. On the other hand, DC to AC conversion is a complicated process and it needs a complex inverter circuit.
  5. Voltage Control: The voltage variation of AC can be easily done using a transformer by stepping up or stepping down the voltage with an online tap changer. On the other hand, In the case of DC voltage variation mechanism is very complex and it needs complicated circuitry.
  6. Voltage variation without loss of energy: The voltage drop can be done through the inductor coil without loss of energy for AC. While DC uses resistors for a voltage drop which consumes energy.
  7. Higher efficiency of AC generator: AC generators are more efficient because of their simpler design, lower electrical losses, reduced friction and wear, and efficient voltage regulation.
  8. Economic Generation: AC generation is more economical than DC generation because the AC system has an established transmission and distribution system. The existing infrastructure reduces the cost of generation. Thus, economic generation is one of the advantages of AC over DC.
  9. Low Transmission losses: AC has lower transmission losses as compared to DC transmission. The reasons for lower transmission losses in AC are Lower current(High voltage transmission), reactive power compensation, and voltage transformation.
  10. Safety: It is safer to interrupt the AC circuit using a circuit breaker because AC does not sustain an arc at the natural zero-crossing of the AC waveform. DC does not have natural zero-crossing and it is more difficult to interrupt DC.

These are the 10 advantages of AC over DC. 

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