What length of a 60 Hz transmission line is considered long?

What length of a 60 Hz transmission line is considered long?

• A. Less than approximately 100 mi (160 km)
• B. Between 100 mi (160 km) and 150 mi (240 km)
• C. Greater than approximately 150 mi (240 km)
• D. Approximately 150 mi (240 km)

Answer: (C)

In transmission line theory, the classification of transmission lines as short, medium, or long is primarily based on the relationship between the line's length and its electrical characteristics at a given frequency, such as 60 Hz for AC power systems. A long transmission line is one where the length is significant enough that the effects of the line's capacitance, inductance, and resistance cannot be ignored, and where the propagation delay becomes relevant for signal transmission. For a typical 60 Hz transmission system, a line is generally considered long if it exceeds approximately 150 miles (or 240 kilometers). This is because at longer distances, the line's parameters—specifically the distributed capacitance and inductance—play a critical role in determining the voltage and current at the receiving end. The behavior of the line can no longer be accurately represented by simple equivalent circuits commonly used for shorter lines. In practical terms, a long line will require more complex calculations involving transmission line theory such as calculating the transmission line parameters (A, B, C, D) using methods like the telegrapher’s equations, due to the significant effects of reactive components on power factor and voltage drop. This classification helps engineers design and implement more effective transmission solutions that can manage losses and stability

In transmission line theory, the classification of transmission lines as short, medium, or long is primarily based on the relationship between the line's length and its electrical characteristics at a given frequency, such as 60 Hz for AC power systems. A long transmission line is one where the length is significant enough that the effects of the line's capacitance, inductance, and resistance cannot be ignored, and where the propagation delay becomes relevant for signal transmission.

For a typical 60 Hz transmission system, a line is generally considered long if it exceeds approximately 150 miles (or 240 kilometers). This is because at longer distances, the line's parameters—specifically the distributed capacitance and inductance—play a critical role in determining the voltage and current at the receiving end. The behavior of the line can no longer be accurately represented by simple equivalent circuits commonly used for shorter lines.

In practical terms, a long line will require more complex calculations involving transmission line theory such as calculating the transmission line parameters (A, B, C, D) using methods like the telegrapher’s equations, due to the significant effects of reactive components on power factor and voltage drop. This classification helps engineers design and implement more effective transmission solutions that can manage losses and stability