##### From Handbook of Electric Power Calculations, Third Edition

**Omar S.Mazzoni, Ph.D., P.E.**

*President*

*Systems Research International, Inc.*

**Marco W.Migliaro, P.E., Fellow IEEE**

*Chief Electrical and I&C Engineer*

*Florida Power & Light*

*Nuclear Division*

## * ***PER-UNIT BASE QUANTITIES**

**PER-UNIT BASE QUANTITIES**

Calculate the per-unit (p.u.) base quantities for a 150-MVA, 13.8-kV, 60-Hz, three-phase, two-pole synchronous, machine that has the following constants: *d*-axis mutual inductance between rotor and stator, *L* _{ad}=0.0056 H; *d*-axis mutual inductance between stator winding *a* and rotor, *L* _{afd}=0.0138 H; mutual inductance between stator winding *a* and *d*-axis amortisseur, *L* _{akd}=0.0054 H; q-axis mutual inductance between rotor and stator, *L* _{aq}=0.0058 H; and mutual inductance between stator winding *a* and *q*-axis amortisseur, amortisseur, *L* _{akq}=0.0063 H. The per-unit system used should be the reciprocal mutual per-unit system. This denotes a per-unit system where the per-unit mutual inductances between the rotor and stator circuits are reciprocal. This also implies that ( *Note:* The bar over symbol denotes a per-unit value.)

### Calculation Procedure

* 1. Select Base Values*

Select VA _{base}=150 MVA, V _{base}=13.8 kV, and * * _{base}=60 Hz. From these values, other base quantities may be derived.

2. Calculate rms Stator Phase Current Base,I_{ s(base)}

3. Calculate Peak Stator Phase Current Base,i_{ s(base)}

The current is

4. Calculate Stator Base Impedance,Z_{ s(base)}

5.Calculate Stator Base Inductance,L_{ s(base)}

*L* _{s(base)}= *Z* _{s(base)}/ ? _{base}=1.270/377=3.37 10 ^{?3} H.

6. Calculate Field Base Current,i_{ d(base)}_{ }

The current is

##### Products & Services

##### Topics of Interest

Hesham E.Shaalan Assistant Professor Georgia Southern University MAJOR PARAMETER DECISIONS The major parameter decisions that must be made for any new electric power-generating plant or unit include...

Abbreviations used in electronics for multiples and sub-multiples T tera 10 12 G giga 10 9 M mega or meg 10 6 k kilo 10 3 d deci 10 ?1 c centi 10 ?2 m milli 10 ?3 ? micro 10 ?6...

A area, attenuation B susceptance, phase function, a field ratio C capacitance, a field ratio D spacing between towers in electrical degrees E electromotive force, voltage E k kinetic energy F P...

CHAPTER 4: SOLUTIONS 4.2.3 Application Example 4.1: Steady-State Analysis of a Nonsalient-Pole (Round-Rotor) Synchronous Machine: Q: A three-phase ( m = 3), four-pole ( p = 4) nonsalientpole...

5.2 Pull-out torque/speed characteristics for the hybrid motor 5.2.1 Circuit representation of the motor The pull-out torque is calculated by establishing a suitable model for the phase circuits and...