Why would a distribution line be considered overloaded?

A distribution line is considered overloaded when it exceeds its MVA (megavolt-ampere) rating. The MVA rating indicates the maximum capacity of the line to safely carry electrical power without overheating or experiencing voltage drops that could lead to failure or decreased efficiency. When the load on a distribution line surpasses this rating, it can cause excessive heating of the conductors, potential damage to the infrastructure, and decreased reliability of the power supply.

This concept is critical in the management of electrical grids, where maintaining power quality and ensuring the safe operation of equipment is paramount. High reactive power, changes in frequency, and lack of transfer capability are factors that can affect the performance of a distribution line, but they do not, by themselves, define an overload condition as clearly as exceeding the MVA rating does.