A single-phase line consists of two long solid conductors, each having a radius of r metre separated by a distance of D metre. What will be capacitance between the conductors?
A single-phase line consists of two long solid conductors, each having a radius of r metre separated by a distance of D metre. What will be capacitance between the conductors?
Right Answer is:
0.0121/[ log (D/r)] µF/km
SOLUTION
The capacitance between the conductors of a 1-ϕ, 2- long solid conductors transmission line is
= π ϵr ϵ∘ / ln(D / r)
where
D = distance of separation between two long solid conductors
r = radius of each long solid conductor
Calculations:
ϵ∘ = 8.85 × 10-12
ϵr = 1 (for air)
π = 3.14
ln (D / r) = 2.303 log (D / r)
From equation ( i )
CAB = (3.14 × 8.85 × 10-12 × 1) / (2.303 log (D / r))
CAB = 0.0121/[ log (D/r)] µF/km