Find the line current if a three-phase star-connected system is c
| Find the line current if a three-phase star-connected system is connected to a 400 V, 50 Hz AC supply. Assume Zph = (9.8 + j10) Ω
A. 28.57 A
B. 16.5 A
C. 10 A
D. 11.44 A
Please scroll down to see the correct answer and solution guide.
Right Answer is: B
SOLUTION
Concept:
In a star-connected three-phase system,
VL = √3 × Vph
And IL = Iph
In a delta connected three-phase system,
VL = Vph
IL = √3 × Iph
Where,
VL is line voltage
Vph is phase voltage
IL is line current
Iph is phase current
Calculation:
Given VL = 400 V
Z = 9.8 + j10 = 14∠45.58
Phase angle \(\phi = {\tan ^{ - 1}}\left( {\frac{{10}}{{9.8}}} \right) = 45.58\)
In a star connected system,
VL = 400 volt =√3 × Vph
Phase current \({I_L} = {I_P} = \frac{{400}}{{14 \times \sqrt 3 }} = 16.5\;A\)