A 400 km 500 kV 60 Hz uncompensated threephase line has a po

A 400 km, 500 kV, 60 Hz uncompensated three-phase line has a positive sequence series impedance i = 0.03 + j0.35 ohm/km and a positive sequence shunt admittance of v = j4.4 times 10^-6 S/km. For this line, calculate: the equivalent pi circuit.

Solution

Using the nominal model, the transmission line ABCD constants are determined.

The line impedance and shunt admittance are

Z = (0.03 + j0.35)(400) = 12 + j140

Y = (j4.4 × 10⁶ )(400) = j1.76 × 10³ siemens

The ABCD constants of the nominal model are;

A = D= (1 + ZY/2 ) = 1 + (12 + j140)(j1.76 × 10³ ) /2 = 0.8768+ j0.0105

B = Z = 12 + j140

C = Y (1 + ZY/4 ) = 0.9384+ j0.0052