Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
Ferranti effect on long overhead lines is experienced when it is
Lightly loaded
On full load at unity power factor
On full load at 0.8 (lag) power factor
In all these cases
Lightly loaded
The Ferranti effect is a phenomenon in long transmission lines where the receiving-end voltage (VRтАЛ) becomes higher than the sending-end voltage (VSтАЛ). This occurs primarily when the line is lightly loaded or operating under no-load conditions.
The Ferranti effect is a phenomenon in long transmission lines where the receiving-end voltage (VRтАЛ) becomes higher than the sending-end voltage (VSтАЛ). This occurs primarily when the line is lightly loaded or operating under no-load conditions.
VRтАЛ>VSтАЛ тАФ Condition at the receiving end for the Ferranti effect
ICтАЛ=j╧ЙCV тАФ Charging current responsible for the capacitive effect
In long overhead lines, the shunt capacitance is significant. Under light-load conditions, the charging current flowing through the line's series inductance creates a voltage drop that is in phase opposition to the load current. This results in a voltage rise at the receiving end, as the capacitive reactance (XCтАЛ) dominates the inductive reactance (XLтАЛ).
Most prevalent in lines longer than 200 km.
Driven by the shunt capacitance of the transmission line.
The effect is negligible in short and medium transmission lines due to lower shunt capacitance.
Managed using shunt reactors at the receiving end to compensate for capacitive current.
Not applicable as this is a parasitic phenomenon
Potential damage to insulation due to overvoltage
Stress on connected equipment at the receiving end
Requires additional reactive power compensation
Design of shunt compensation equipment
Insulation coordination for EHV/UHV lines
The effect is mathematically represented using the ABCD parameters where VRтАЛ=AVSтАЛтАЛ and A=cos(╬▓l). As the line length l increases, A<1, leading to VRтАЛ>VSтАЛ.
Option B and C are incorrect because as load increases, the lagging power factor current creates a voltage drop across the series impedance (R+jX), which significantly reduces the receiving-end voltage.
A is correct тАФ The Ferranti effect leads to an increase in receiving-end voltage over sending-end voltage specifically during light-load or no-load conditions.
In competitive exams, always remember that Ferranti effect is synonymous with 'No load/Light load' and 'Long lines'. If the question asks for the cause, look for 'Line Capacitance'.