Ferranti effect

English

Etymology

First observed during the installation of underground cables in Sebastian Ziani de Ferranti's 10,000 volt distribution system in 1887.

Noun

Ferranti effect (plural Ferranti effects)

1. An increase in voltage occurring at the receiving end of a long transmission line, above the voltage at the sending end. This occurs when the line is energized, but there is a very light load or the load is disconnected. The capacitive line charging current produces a voltage drop across the line inductance that is in-phase with the sending end voltages considering the line resistance as negligible.

   The Ferranti effect is much more pronounced in underground cables, even in short lengths, because of their high capacitance.