Keep in mind that the numerical solutions provided after each part have occasionally been known to be incorrect. Ignore part (b) if part (a) is too long. I am not familiar with this type of question, so I will let you judge based on the work required.
4)
0.8 P.F. lagging at B, 120 A at unity P.F. at C, and 70 A at 0.866 lagging at D, the load currents being referred to the supply voltage at A. The impedance of the various sections are:
Section AB = (1 + j0.6)
Section BC = (1.2 + j0.9)
Section CD = (0.8 + j0.5)
Section DA = (3 + j2)
Calculate the currents in various sections and station bus-bar voltages at B, C, and D. (LA = 139.7 - j42.8 A, Icp = -20.3 - j12.8 A, Ipa = -80.9 + j22.2) (Vs = 6185.62 + j41.02 V, Vc = 6054.46 + j115.39 V, Vp = 6064.3 + j95 V)
b) The three line leads of a 400/230 V, 3-phase, 4-wire supply are designated as R, Y, and B respectively. The fourth wire or neutral wire is designated as N. The phase sequence is RYB. Compute the currents in the four wires when the following loads are connected to this supply: From R to N: 20 kW, unity power factor From Y to N: 28.75 kVA, 0.866 lag From B to N: 28.75 kVA, 0.866 lead If the load from B to N is removed, what will be the value of currents in the four wires? Ig = 89.96 A, Iy = 125 A, I = 125 A, IN = 129.54 A, 66.03)
