Three Winding Transformer - Harmonics Tab

Figure 1: Harmonics Tab

Use the Harmonics tab to indicate whether this equipment item is introducing harmonics into your power system.

Resistance Factor

EasyPower offers two methods for calculating RH:

  • Resistance varying with a power of the harmonic (R-EXP):

    • RH = RFund * H R-EXP

  • Resistance varying with a percent eddy current factor (%ECF):

    • RH = RFund * (1+ECF*H2)/(1+ECF)

EasyPower defaults all skin effect correction to R-EXP and a value of 0.5.

Typical Resistance Correction Factors

  R-EXP %ECF

Transformer

0.5-1.0

1.0-3.0

Utility

0.0-0.8

    -

Generator

0.3-0.6

    -

Line/Cable

0.5

    -

Reactor

0.5-1.0

0.8-3.0

Motor

0.2-0.4

    -

Fundamental Amps

Use to set the fundamental amps. The options are as follows:

  • Equipment Rating sets Fundm Amps to the equipment rating of the item described in the Specifications tab. 
  • User Specified activates the Fundm Amps field, enabling you to specify a value. 

To use fundamental current calculated by power flow, select Calculated from Power Flow in the Summation Fundamental Voltage area of the Harmonics Options > Control dialog box.

Option Description

Pri Fundm Amps

Calculated rated amps on the primary side.

Sec Fundm Amps

Calculated rated amps on the secondary side.

Ter Fundm Amps

Calculated rated amps on the tertiary side.

Rated eddy-current loss, Pec-r

Eddy-current loss under rated conditions expressed as a percentage of rated I2R loss.

More Information