A 1000/1 A, 5 VA, unity-power-factor current transformer has 1000 secondary turns. At primary current 1000 A, ratio error is −0.1% and phase error is 3.438 minutes. Find its magnetization-current magnitude in A, to two decimal places.
For a unity-power-factor burden, the small phase displacement is primarily due to the quadrature magnetizing component of excitation current. Convert $\delta=3.438$ arcminutes to radians: $\delta=3.438\pi/(180\times60)=0.0010001$. Referred to the primary, $I_m\simeq I_p\delta=1000(0.0010001)=1.00$ A. The ratio error describes the in-phase excitation component; it is not added directly to this magnetizing component.
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