Question

 In a long or medium transmission line, the phenomenon causing receiving end voltage to be greater than sending end voltage under no-load condition is called:

1. skin effect
2. Corona effect
3.  loading effect
4. Ferranti effect

Answer 1

Correct Answer - Option 4 : Ferranti effect

During the no-load condition, the current flowing is only charging current due to line capacitance. It increases the capacitive var in the system.

Since the line is under no load the line inductance will be less. Therefore, the capacitive var becomes greater than inductive var during no load or light load condition.

Due to this phenomenon, the receiving end voltage becomes greater than the sending end voltage. This effect is also called the Ferranti effect.