As an electrical engineering expert, I can provide you with a comprehensive explanation of why we use alternating current (AC) instead of direct current (DC) for power transmission and distribution.

Firstly, alternating current is more suitable for long-distance transmission than direct current. The reason for this lies in the properties of AC and the use of transformers.
Transformers are devices that can increase or decrease the voltage of an AC supply without changing its frequency. This is crucial for power transmission because high voltages reduce the amount of current required to transmit a given amount of power, which in turn reduces the energy lost as heat in the transmission lines. The formula that governs this relationship is known as Ohm's Law and the power equation, which states that the power (P) transmitted is equal to the voltage (V) times the current (I), or \( P = VI \). By increasing the voltage, the current—and consequently the energy lost—can be decreased.

Secondly, AC systems are more flexible in terms of generation and distribution. Multiple AC generators can be connected in parallel to supply a common load, which is not as easily achievable with DC. This parallel operation allows for better load sharing and redundancy in power systems. Moreover, AC power can be generated by a variety of sources including fossil fuels, nuclear power, and renewable sources like wind and solar, which all can be synchronized to produce a stable AC supply.

Thirdly, **the infrastructure for AC is well-established**. Most of the electrical grid around the world is designed to handle AC. This includes not only the power plants and transmission lines but also the distribution systems and the electrical devices in homes and businesses. Changing over to a DC system would require a massive overhaul of this infrastructure, which is not economically feasible.

Fourthly, **AC power is safer for certain applications**. For example, in high-voltage transmission lines, AC can create a corona discharge that helps to keep the lines clean by ionizing the air and preventing the buildup of contaminants. This is less of an issue with DC, which can lead to a buildup of contaminants over time, requiring more maintenance.

Fifthly, **AC has advantages in terms of motor drives**. Most electric motors are designed to run on AC because AC motors are simpler, more reliable, and require less maintenance than their DC counterparts. AC induction motors, for instance, do not have brushes or commutators that can wear out over time.

Lastly, **the conversion between AC and DC is relatively straightforward**. Many electronic devices and appliances that require DC can easily be powered from an AC supply using a simple rectifier circuit. This allows for the use of AC for transmission and distribution while still providing the benefits of DC for end-use applications.

In summary, the use of alternating current for power transmission and distribution is primarily due to its efficiency over long distances, the ease of voltage transformation, the flexibility in generation and distribution, the established infrastructure, safety considerations, advantages in motor drives, and the ease of conversion to DC for end-use devices.

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Since high voltages are more efficient for sending electricity great distances, AC electricity has an advantage over DC. This is because the high voltages from the power station can be easily reduced to a safer voltage for use in the house. Changing voltages is done by the use of a transformer.Feb 13, 2016read more >>