1-Phase 3-Winding Transformer

 Name for Identification

Text

Optional text parameter for identification of the component.

 Transformer MVA

REAL

Constant

The apparent power rating of the transformer [MVA].

Base Operation Frequency

REAL

Constant

The base frequency of the electrical system, in which the transformer resides [Hz].

Leakage Reactance (#-#)

REAL

Constant

Enter the individual leakage reactances between the specified transformer windings. This can be calculated based on short-circuit test results, and is based on the transformer base impedance [pu].

Eddy Current Losses

REAL

Constant

The eddy current portion of the no-load core losses, based on transformer rating. Hysteresis losses may also be added here if hysteresis is not modeled. Winding losses are not to be included in this value [pu].

Copper Losses (#-#)

REAL

Constant

Enter the copper losses between the specified transformer windings. These resistances are placed in series with the windings and are based on the transformer rating [pu].

Ideal Transformer Model

Choice

Select Yes or No. This input must be Yes when modeling core saturation

NOTE: 'Ideal' transformer should not be confused with an ideal ratio changer. 'Ideal' here simply means that the magnetizing branch has been eliminated (leakage reactance is still present as well).

Tap Changer on Winding

Choice

Select None, #1 or #2.

Select the winding number on which to place the on-line tap changer (or none).

See On-Line Tap Changer for more details.

Graphics Display

Choice

Select Windings or Circles.

 Winding # Voltage (RMS)

REAL

Constant

The RMS voltage rating of the corresponding winding # [kV].

 Saturation Enabled

Choice

Select Yes or No to enable or disable the core saturation routine.

NOTE: Always set the transformer to 'ideal' when enabling saturation. Otherwise, both the magnetizing branch and the saturation routine will both be used.

Place Saturation on Winding

Choice

Select Middle, Winding #1, #2 or #3.

Middle is the preferred option, whereas specifying the actual winding number is left in for legacy support. Selecting the winding number will place the saturation current injection directly on that winding. Note that this can cause ideal loop problems when performing certain types of studies (such as black start).

See Adjusting Saturation Properties for more details.

Hysteresis

Choice

Select None, Basic Model, or Jiles-Atherton.

The Basic Model models hysteresis based a translation on the transformer l-I characteristic, whereas the Jiles-Atherton model involves a conversion from an M-H loop to a B-H loop characteristic.

See Transformer Magnetic Hysteresis for more details.

Inrush Decay Time Constant

REAL

Constant

The decay time for the transformer inrush current [s].

This option is enabled only when Hysteresis | None is selected.

Time to Release Flux Clipping

REAL

Constant

Time interval from start-up in which the model will 'clip' (limit) the calculated flux linkage values. This is simply a modeling 'trick' to prevent instability at start-up [s].

This option is enabled only when Hysteresis | None is selected.

Air Core Reactance

REAL

Constant

Usually approximately twice the leakage reactance [pu].

Magnetizing Current

REAL

Constant

The percentage of primary winding current that flows through the transformer magnetizing susceptance. This value can be calculated based on the open-circuit test results. The magnetizing susceptance is calculated based on this value [%].

Knee Voltage

REAL

Constant

The knee point voltage corresponding to the knee point of the saturation curve [pu].

Remanent Flux

REAL

Constant

Loop Width

REAL

Constant

Nominal Flux Density (T)

REAL

Constant

Magnetic Material

Choice

 Domain Flexing Parameter

REAL

Constant

This parameter represents the contribution of reversible magnetization process.

Domain Pinning Parameter

REAL

Constant

This parameter has a direct impact on the width of the loop [A/m].

Parameter to Adjust K with M

REAL

Constant

This parameter adjusts the domain pinning parameter with magnetization for better representation of the shoulder area.

Inter-Domain Coupling

REAL

Constant

Saturated Anhysteretic Magnetization

REAL

Constant

[A/m].

Coefficient # of Anysteretic Curve

REAL

Constant

Name for Magnetizing Current [kA]

REAL

Output

Name for the magnetizing current [kA].

Name for Flux Linkage [kWb-N]

REAL

Output

Name for the calculated flux linkage [kWb-N].

Name for Magnetic Field Intensity

REAL

Output

Name for the magnetic field intensity.

This output is enabled only when Hysteresis | Jiles-Atherton and Saturation Enabled | Yes is selected.

Name for Flux Density [T]

REAL

Output

Name for the flux density [T].

Name for Winding # Current

REAL

Output

Name for the specified winding current [kA].