Per-Unit Conversion for Machine Parameters

Impedance Conversion Equations

For machine impedance parameters (resistance, inductance, and reactance), the relationships between SI and per-unit values are defined by these equations:

$R=\frac{R_{(SI)}}{R_{base}}$

$$L=X=\frac{X_{(SI)}}{X_{base}}$$

where:

• R_(SI) is the resistance, expressed in Ω.

• R_base is the per-unit base resistance, expressed in Ω.

• R is the per-unit resistance.

• X_(SI) is the reactance, expressed in Ω.

• X_base is the per-unit base reactance, expressed in Ω.

• X is the per-unit reactance.

• L is the per-unit inductance.

Magnetic Flux Linkage Conversion Equations

For machine magnetic flux linkage parameters, the relationship between SI and per-unit values is defined by

$\psi =\frac{{\psi }_{(SI)}}{{\psi }_{base}}$

where:

• ψ_(SI) is the magnetic flux linkage, expressed in Wb.

• ψ_base is the per-unit base magnetic flux linkage, expressed in Wb.

• ψ is the per-unit magnetic flux linkage.

Related Topics

• Per-Unit System of Units