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Per-Unit System Converter
Actual → Per-Unit
Per-Unit → Actual
Change Base
Base Values (3-Phase System)
Results
Derived Base Values
Base Current (I_base)
--A
Base Impedance (Z_base)
--Ω
Per-Unit Values
Show Formulas
Per-Unit System (3-Phase):
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Base Quantities:
S_base = Base apparent power (MVA)
V_base = Base line-to-line voltage (kV)
Derived Base Values:
I_base = S_base / (√3 × V_base) × 1000 [Amps]
Z_base = V_base² / S_base × 1000 [Ohms]
Conversion to Per-Unit:
V_pu = V_actual / V_base
I_pu = I_actual / I_base
Z_pu = Z_actual / Z_base
S_pu = S_actual / S_base
Changing Base:
Z_new = Z_old × (S_new/S_old) × (V_old/V_new)²
Note: Per-unit values are identical on either side
of an ideal transformer (the great advantage of p.u.)