The limitation of high transmission voltage in an AC system is __________.

Explanation:

High Transmission Voltage in AC Systems

Definition: High transmission voltage in alternating current (AC) systems refers to the practice of transmitting electrical power at high voltage levels, typically in the range of hundreds of kilovolts (kV) or more. This approach is widely used in power transmission networks to efficiently transport electricity over long distances.

Working Principle: The transmission of electrical power involves the generation, transmission, and distribution of electricity. High voltage transmission is employed to reduce the current flowing through the transmission lines. According to the power transmission formula, P = VI (where P is power, V is voltage, and I is current), increasing the voltage (V) allows for a reduction in current (I) for the same amount of power (P). This reduction in current minimizes energy losses due to the resistance of the transmission lines.

Advantages of High Transmission Voltage:

• Reduced Power Losses: By transmitting power at higher voltages, the current through the transmission lines is reduced, leading to lower resistive losses (I²R losses). This improves the overall efficiency of the power transmission system.
• Improved Transmission Efficiency: Higher voltage levels enable the transmission of larger amounts of electrical power over long distances with greater efficiency.
• Reduced Conductor Size: Lower current levels allow for the use of smaller conductor sizes, which can reduce the material and installation costs of transmission lines.
• Enhanced Load Capacity: High voltage transmission lines can carry more electrical power, allowing for the support of larger and more widespread electrical grids.

Disadvantages of High Transmission Voltage:

• Increased Cost of Insulation: The most significant limitation of high transmission voltage in AC systems is the increased cost associated with insulating the conductors. High voltage levels require better and more expensive insulation materials to prevent electrical breakdown and ensure the safety and reliability of the transmission system.
• Complexity in Design: High voltage transmission systems require careful design and engineering to manage issues such as corona discharge, electromagnetic interference, and insulation coordination.
• Higher Equipment Costs: Transformers, circuit breakers, and other high voltage equipment are more expensive and require specialized designs to handle the increased voltage levels.

Correct Option Analysis:

The correct option is:

Option 4: The cost of the insulating conductor.

This option correctly identifies the primary limitation of using high transmission voltage in AC systems. The cost of insulating conductors increases significantly with higher voltage levels. This is because the insulation must be capable of withstanding higher electrical stresses to prevent breakdown and ensure reliable operation. The need for advanced insulation materials and techniques drives up the overall cost of the transmission system.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: The increased efficiency.

While it is true that high transmission voltage can lead to increased efficiency by reducing resistive losses, this is not a limitation but rather a benefit of using high transmission voltage.

Option 2: The increased power.

High transmission voltage allows for the transmission of larger amounts of power over long distances, but this is also a benefit rather than a limitation. The ability to transmit more power is one of the reasons for using high voltage in transmission systems.

Option 3: The increased line conductor.

This option is incorrect because high transmission voltage actually allows for the use of smaller conductor sizes, as the current is reduced. Therefore, it does not represent a limitation of high transmission voltage.

Conclusion:

Understanding the advantages and limitations of high transmission voltage in AC systems is crucial for designing efficient and reliable power transmission networks. While high voltage transmission offers several benefits, including reduced power losses and improved efficiency, the increased cost of insulating conductors remains a significant challenge. Addressing this limitation requires careful consideration of insulation materials and techniques to ensure the safe and economical operation of high voltage transmission systems.