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Zigzag Transformer Data

This dialog box includes the following areas and tabs:

Figure 1: Zigzag Data Dialog Box

Connection Information

Option Description
ID Name Uniquely identifies the transformer. This ID name is sometimes referred to as the transformer name, and can be up to 12 characters long. The names default to TZ-1, TZ-2, TZ-3, and so on as you enter new transformers on the one-line diagram, but you can change those names later if needed.
From Bus The bus from which the transformer connects, which must already exist on the one-line. For reference, the From Bus base kV is displayed next to the bus name.

Specifications

Option Description
Voltage Rating (kV) Transformer nameplate rated kV.
Impedance (Ohms) Transformer nameplate impedance in ohms. This is the impedance between each line terminal and neutral.
R Transformer neutral ground resistance in ohms.
jX Transformer neutral ground reactance in ohms.

Harmonics

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

Figure 2: Harmonics Tab

Option Description
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.

Location

See Location for more information.

Imported Data

This tab is read-only and appears only if you have imported data from an SKM Data Format file. See Importing an SKM Format File for more information.

Comments

See Comments for information.

Hyperlinks

See Hyperlinks for information.

More Information

Database Technical Reference  
     

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EasyPower Version 9.7

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Help was last updated on 2/8/2016