Variables
Description
What is this formula?
This formula calculates the percentage voltage rise caused by the Ferranti Effect, a phenomenon that occurs in long AC transmission lines under light-load or no-load conditions.
When to use it
Use this formula when studying long transmission lines, reactive power effects, voltage regulation, and high-voltage power system behavior.
Example
A transmission line operates with:
Sending-end voltage = 220 kV
Receiving-end voltage = 228 kV
Formula:
ΔV = ((Vr − Vs)/Vs) × 100
Substitution:
ΔV = ((228 − 220)/220) × 100
Result:
ΔV = 3.64%
Applications
Long transmission line studies
Reactive power analysis
Voltage regulation evaluation
Power system planning
High-voltage network design
Note
The Ferranti Effect is most significant in long high-voltage AC transmission lines operating under light load. The effect is caused by line capacitance generating reactive power, which can cause the receiving-end voltage to exceed the sending-end voltage. More detailed transmission-line models are required for accurate engineering studies.