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Homework Statement
Figure shows a 50 Hz, highvoltage, transmission line. The relationships between the sending and receiving end voltages and currents are given by the complex ABCD equations:
where 'S' stands for sendingend and 'R' stands for receivingend
(a) Given the parameter values in TABLE C and an opencircuit received voltage measured as 88.9 kV, calculate the values of
(b) If the line is modelled by the Tcircuit of FIGURE 3(b), see if you can estimate the primary line coefficients R, L, G and C. The line is 50 km long.
The Attempt at a Solution
I am currently doing part (b), if
[ A B ] = [ 1+Z1*Y2 Z1+Z3+Z1*Y2*Z3 ]
[ C D ] = [ Y2 1+Y2*Z3 ]
Then Y2 = C =j0.001349S
Also A=1+Z1*Y2
Z1= (A1)/Y2
Z1=(0.8698+j0.035421) / j0.001349
Z1= 26.268+j96.558 Ω
Z1=Z3
So as Z1 & Z3 in series:
R+jXL = Z1*2
R+jXL = 52.536+j193.116 Ω
R coefficient = R / 50 = 1.051Ω/km
L= XL / 2πf = 193.116 / 2π*50 = 0.614707H
L coefficient = 0.614707 / 50 = 12.294mH/km
G coefficient = 0 as Y2 branch is not resistive only 'imaginary'
XC = 1 / Y2 = j741.290 which is capacitive
C= 1/ XC*2πf = 1 / j741.290*2π*50 = 4.29μF
C coefficient = 4.29μF / 50 = 85.88pF/km
How does that look to you smarter people?
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