What length of a 60 Hz transmission line is classified as long?

In electrical engineering, the classification of transmission lines as short, medium, or long is primarily based on the length of the line relative to the wavelength of the signal being transmitted. For a frequency of 60 Hz, the wavelength is quite long, approximately 3,100 miles (or about 5,000 kilometers).

A long transmission line is typically defined as one that is more than one-tenth of the wavelength of the operating frequency. Given the relatively low frequency of 60 Hz, any transmission line exceeding approximately 150 miles (240 km) would be classified as long. This distinction is important because long transmission lines exhibit different electrical characteristics, such as significant inductance and capacitance, which must be considered in their design and operation.

Thus, the classification of greater than 150 miles (240 km) as long aligns with the common standards in electrical engineering and is critical for ensuring proper transmission line analysis and performance. This understanding helps engineers effectively design and manage long-distance power transmission systems.