Question

For distant transmission of electric power, an alternating current (ac) is considered to be advantageous over direct current (dc). Why?

Answer 1

Step 1: Rationale for AC's superiority in power transmission
Alternating current (AC) is preferred over direct current (DC) for long-distance power transmission due to advantages in efficiency, cost, and ease of voltage transformation.

Step 2: Advantages of AC
1. Effortless Voltage Level Adjustment:
AC's primary advantage is its facile voltage modification via transformers. Stepping up voltage for long-distance transmission reduces current, thereby minimizing resistive losses. Upon arrival, voltage is stepped down for safe usage. DC transformation is significantly more complex.

2. Reduced Energy Losses:
Transmitting power over extended distances with high-voltage AC significantly cuts energy losses caused by wire resistance. Since power loss (\( P = I^2 R \)) is proportional to the square of the current, increasing voltage to decrease current substantially lowers power dissipation, enhancing AC's efficiency for long-haul transmission.

3. Economic Feasibility:
AC power generation and transmission equipment, including transformers and generators, are less expensive and simpler than their DC counterparts, especially for long distances. AC transmission systems are thus more economical and globally prevalent.

4. Simpler Technology:
AC generation, distribution, and application in electrical devices are simpler. AC technology is more mature and widespread for large-scale power distribution compared to DC.

Step 3: Summary
AC is advantageous for long-distance power transmission over DC due to its simple voltage transformation, reduced energy losses, economic benefits, and less complex technology.