FERRANTI EFFECT

Ferranti Effect is an electrical engineering phenomenon, wherein there is a rise in voltage occurring at the end of a long transmission line when its load is disconnected. We usually observed that the sending voltage is greater than the receiving end voltage. From the equation:
Vs = Vr + (current x impedance), the receiving voltage is lower since it is the difference of the Voltage Sending and the voltage drop.

The operative words here are, long transmission lines and disconnected load. Under no load conditions, theoretically, Vs=Vr.  Furthermore, one classification of transmission lines is according to its length or circuit km. In long transmission lines, you are going to take into consideration the effect of capacitance and the charging current of the lines.

Due to the voltage drop across the line inductance (due to charging current) being in phase with the sending end voltages, capacitance and inductance is responsible to produce this phenomenon.

For more about the Ferranti Effect, you may click on these free links/pdf
LINK 1
LINK 2
Radiation effects on power transistors (Ferranti semiconductors ; 1)