7/25/2019 Per-Unit and Base Impedance Calculation

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Change of Base Formula

Where:

ZBASE= Base Impedance

KVLL= Base Voltage (Kilo Volts Line-to-Line)

MVA3= Base Power

ABASE= Base Amps

ZPU= Per Unit Impedance

ZPU GIVEN= Given Per Unit Impedance

Z = Impedance of circuit element (i.e. Capacitor, Reactor,

Transformer, Cable, etc.)

XC= Capacitor Bank Impedance (ohms)

XC-PU= Capacitor Bank Per Unit Impedance

PER-UNIT AND BASE IMPEDANCE CALCULATOR

Calculator-1

Known variables:

Formulas and Variables

7/25/2019 Per-Unit and Base Impedance Calculation

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Capacitor Bank Per-Unit Calculations

Motor Per-Unit Calculations

MVAR3= Capacitor Bank 3-Phase Rating

X" = Motor Sub-Transient Reactance

LRM = Locked Rotor Multiplier

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