Consider a single-phase electric system shown in Figure 3.33. Transformers are rated as follows:

X-Y 15 MVA, 13.8/138 kV, leakage reactance 10\%

Y-Z 15 MVA, 138/69 kV, leakage reactance 8\%

With the base in circuit Y chosen as \(15 \mathrm{MVA}, 138 \mathrm{kV}\), determine the perunit impedance of the \(500 \Omega\) resistive load in circuit \(Z\), referred to circuits Z, Y, and X. Neglecting magnetizing currents, transformer resistances, and line impedances, draw the impedance diagram in per unit.

X 1:10 X-Y Y 2:1 Y-Z N 500