What does Line Loading mean?
Line loading is the process of adding load to power transmission lines by installing the necessary equipment, such as the loading coils, in series. The loading coils are typically 88 millihenry coils and are installed at intervals of 6000 feet. Line loading can also refer to the actual load on the transmission line, and the loading is measured in real power (MW), apparent power (MVA) or amps (A).
Techopedia explains Line Loading
A transmission line in a power transmission system consists of various components like the conductor, ground wire, insulator and connectors as well as many other components which must be carefully designed depending upon factors like climatic data and reliability levels to allow for maximum efficiency. Electric power is transmitted through these lines from generating stations to different load centers. The design of transmission lines involves calculating the necessary climatic loading, loads corresponding to security requirements and safety.
The load flow in the lines depends upon the associated system, voltage magnitudes, angles and the active and reactive power. For a line with lagging load, the received voltage is lower and for leading loads, the received load is higher.
Hence, to decrease the voltage at the end of the transmission line, lagging (inductive) loads are added at the end of a line and to increase the voltage at the end of the line, leading (capacitive) loads are added at the end of the line.