POWER SYSTEM LAB
PRESENTATION
PRESENTED BY- PRESENTED TO-
Ghanendra Kumar Joshi Prof- Garima Chandrakar Mam
AIM
• To Study the Ferranti Effect of Transmission Lines/ Cable.
REQUIREMENT
NAME
Motor Generator
Transformer
Transmission Line
Ammeter
Voltmeter
Rheostat
THEORY
• FERRANTI EFFECT –
A Long Transmission line/cable draws a substantial
quantity of charging current. If such a line/cable is open-
circuited or very lightly loaded at the receiving end. The
voltage at the receiving end may become greater than
the voltage at the sending end due to capacitive
reactance. This is known as the Ferranti Effect.
THEORY
• Both capacitance and inductance are responsible for producing this
effect.
• The capacitance(which is responsible for charging current) is
negligible in short lines but significant in medium lines and
appreciable in long lines. Hence this phenomenon occurs in medium
and long lines.
CIRCUIT DIAGRAM
CIRCUIT DIAGRAM:-
The figure shown below is representing a transmission line by an equivalent
pi(π)-model. The voltage rise is proportional to the square of the line length.
In the phasor diagram shown above
OM = receiving end voltage Vr
OC = Charging current drawn by capacitance = Ic
MN = Resistive drop
NP = Inductive reactance drop
Therefore; OP = Sending end voltage at no load and is less than receiving end voltage
(Vr) Since, resistance is small compared to reactance.
Receiving end voltage is greater than sending end voltage and this effect is called
Ferranti Effect.
PROCEDURE
• Select the initial length of the line (say 30 km).
• Start the motor generator set.
• Note down the sending end voltage Vi, sending end current Ii,and
receiving end voltage.
• Disconnect the supply of the motor generator.
• Increase the length of the line.
• Repeat steps 2-5.
OBSERVATION VOLTAGE
How to reduce Ferranti Effect:-
To reduce Ferranti effect we use Shunt Reactor
• A shunt reactor is a piece of electrical eq
uipment used in high-voltage power tran
smission systems to stabilize the voltage
during load variations
.
•
It is used to increase the power and ener
gy system efficiency as it absorbs and c
ompensates the reactive power in cables
Fig: Shunt Reactor and long high voltage transmission lines
CONCLUSION
• The Study of the Ferranti Effect has been done.
PRECAUTIONS
• The supply must be turned off while wiring.
• Always wear dry rubber shoes while handling electrical wiring or equipment.
• Electrical connection should be clean and tight to avoid sparking.
• Old and Damaged wiring should be replaced regularly.
THANK YOU
