Power factor correction of transformer
Power factor correction of a linear inductive load is exactly the same as tuning a parallel circuit of a capacitor and inductor. You pick a capacitor that works with the value of the transformer's magnetizing inductance to satisfy this: -

60Hz = \$\dfrac{1}{2\Pi\sqrt{L_M.C}}\$ 

Where \$L_M\$ is the transformer's magnetizing inductance and C is the capacitor chosen to "neutralize" the current taken by the coil.

For a pure lossless inductance and capacitance, the resultant current taken from the supply is zero.

If your transformer primary indicates an inductive reactance at 60Hz of 300 ohms, the magnetizing inductance value is this divided by \$2\Pi\times 60\$ = 0.8 henries.

The capacitive reactance required is 300 ohms and this is 8.8 uF. As a sanity check: -

F = \$\dfrac{1}{2\Pi\sqrt{0.8\times 8.8\times 10^{-6}}}\$ = 59.98Hz