A three-phase underground distribution line is operated at 23 kV. The three conductors are insulated with 0.5-cm solid black polyethylene insulation and lie flat, side by side, directly next to each other in a dirt trench. The conductor is circular in cross section and has 33 strands of aluminum. The diameter of the conductor is 1 .46 cm. The manufacturer gives the GMR as 0.561 cm and the cross section of the conductor as 1 .267 cm 2. The thermal rating of the line buried in normal soil whose maximum temperature is 30°C is 350 A. Find the dc and ac resistance at 50°C and the inductive reactance in ohms per kilometer. To decide whether to consider skin effect in calculating resistance, determine the percent skin effect at 50°C in the ACSR conductor of the size nearest that of the underground conductor. Note that the series impedance of the distribution line is dominated by R rather than XL because of the very low inductance due to the close spacing of the conductors.