The standard per-unit impedance Z_pu of a system component on new base quantities is calculated using:

AZ_pu(new) = Z_pu(old) * (MVA_old / MVA_new)^2

BZ_pu(new) = Z_pu(old) * (kV_old / kV_new)^2 * (MVA_new / MVA_old)

CZ_pu(new) = Z_pu(old) * (kV_new / kV_old)^2 * (MVA_new / MVA_old)

DZ_pu(new) = Z_pu(old) * (kV_new / kV_old) * (MVA_old / MVA_new)

Explanation

Per-unit impedance change of base formula is Z_pu_new = Z_pu_old * (V_base_old / V_base_new)^2 * (S_base_new / S_base_old).

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