EEE 471/591: Power System Analysis [Face-to-Face]

Homework #6

Problem 1 (25 Points)

A 200-km, 230-kV, 60-Hz, three-phase line has a positive-sequence series impedance z = 0.08 + j0.48 Ω/km and a positive-sequenceshunt admittance y = j3.33 × 10−6  S/km. At full load, the line delivers 250 MW at 0.99 p.f. lagging and at 220 kV. Using the π circuit for medium-length line, calculate: (a) the ABCD parameters, (b) the sending-end voltage and current, and (c) the percent voltage regulation.

Problem 2 (25 Points)

A 400-km, 500-kV, 60-Hz, uncompensated three-phase line has a positive-sequence series impedance z = 0.03 + j0.35Ω/km and a positive-sequenceshunt admittance y = j4.4 × 10−6  s/km. Calculate: (a) ZC, (b) (yl), and (c) the exact ABCD parameters for this line.

Problem 3 (25 Points)

A 500-kV, 300-km, 60-Hz three-phase overhead transmission line, assumed to be lossless, has a series inductance of 0.97 mH/km per phase and ashunt capacitance of 0.0115μF/km per phase. (a) Determine the phase constant β, the surge impedance  ZC, the velocity of propagation, and the wavelength λ of the line. (b) Determine the voltage, current, real and reactive power at the sending end, and the percent voltage regulation of the line if the receiving-end load is 800 MW at 0.8 power factor lagging and at 500kV.

Problem 4 (25 Points)

A 60-Hz, 230-km, three-phase overhead transmission line has a series impedance z = 0.8431∠79.04°Ω/km and ashunt admittance  y = 5. 105 × 10−6∠90° S/km. The load at the receiving end is 125 MW at unity power factor and at 215 kV. (a) Find the ABCD parameters of the line. (b) Determine the voltage, current, real and reactive power at the sending end. (c) Determine the parameters Z' and 2/Y' for the equivalent π circuit, and draw the equivalent π circuit. (d) Determine the theoretical maximum power at the receiving end (PR(max)) of the line. Assume|VS| = |VR| = 215 kV.