Three-Phase Transformer (Two Windings)
Three-phase transformer with variable connection of windings.
blockType: AcausalElectricPowerSystems.Passive.Transformers.ThreePhaseTwoWindingSPS
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Description
If the magnetic fluxes are not set, their initial values are automatically calculated so that the simulation starts in steady state.
The scattering inductance and resistance of each winding are set in OE based on the rated power of the transformer Pn and the rated voltage of the winding (V1 or V2).
The two windings of the transformer can be connected as follows:
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Star
-
A star with a neutral
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A star with a grounded neutral
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Star triangle (D1), a triangle 30 degrees behind the star
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Star triangle (D11), a triangle with a 30 degree advance of the star
When selecting a star with a neutral for the primary winding, an input port labeled N is added to the block. When selecting a star with a neutral, an additional output port marked n appears on the secondary winding.
The designations D1 and D11 refer to the conventional clock face, which assumes that the phase of the reference voltage of the star is at 12 o’clock. The reference voltages for junctions D1 and D11 are located respectively at 1 hour (the triangle is 30 degrees behind the star) and at 11 hours (the triangle is 30 degrees ahead of the star).
For more information about the operating modes of a three-phase system connected according to the Triangle scheme, see Recommendations for delta connection of transformer windings.
Standard designations of winding connections
The symbol for a two-winding three-phase transformer uses two letters followed by a number. The first letter (Y or D) indicates the connection of the high-voltage windings in the form of a star or triangle. The second letter (y or d) indicates the connection of the low-voltage windings in the form of a star or triangle. An integer from 0 to 12 indicates the position of the reference voltage of the positive sequence of the lowest voltage on the conventional clock face when the reference voltage of the positive sequence of the highest voltage is at 12 o’clock.
The following three figures show examples of standard winding connections. The dots indicate the polarity signs, and the arrows indicate the position of phase A on the primary (VN) and secondary (NN) windings. The phases are assumed to rotate counterclockwise, so increasing numbers indicate an increase in phase shift.
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Yd1: The HH winding (D) is 30 degrees behind the HH winding (Y). The Winding 2 connection parameter is set to
D1.
-2.png)
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Dy11: The HH winding (Y) is ahead of the HH winding (D) by 30 degrees. The Winding 1 connection parameter is set to
D1.
-3.png)
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Dy1: The HH winding (Y) is 30 degrees behind the HH winding (D). The Winding 1 connection parameter is set to
D11.
-4.png)
You can imagine many other relationships with a phase shift from 0 to 360 degrees (in 30 degree increments) by combining the phase shift. +30 or -30 degrees, provided by the settings of the D1 and D11 block parameters, and in some cases, an additional phase shift. +/-120 degrees, obtained by connecting the output terminals of the triangular winding to the corresponding phases of the network.
The table explains how to configure the block. Three-Phase Transformer (Two Windings) to get shared connections.
| Position on the dial | Phase shift (degrees) | Connection | Connecting the primary winding | Connection of the winding 2 | Connecting the triangle winding to a three-phase network |
|---|---|---|---|---|---|
0 |
0 |
Yy0 |
Y |
Y |
− |
Dd0 |
D1 |
D1 |
abc |
||
1 |
−30 |
Yd1 |
Y |
D1 |
abc |
Dy1 |
D11 |
Y |
abc |
||
2 |
−50 |
Dd2 |
D11 |
D1 |
abc |
5 |
−150 |
Yd5 |
Y |
D1 |
bca |
Dy5 |
D11 |
Y |
cab |
||
7 |
+150 |
Yd7 |
Y |
D11 |
cab |
Dy7 |
D1 |
Y |
bca |
||
10 |
+50 |
Dd10 |
D1 |
D11 |
abc |
11 |
+30 |
Yd11 |
Y |
D11 |
abc |
Dy11 |
D1 |
Y |
abc |
For example, to get the Yd5 connection, set the Winding 1 connection parameter to Y, and Winding 2 connection — D1 and connect the mains phases to the secondary winding as follows:
-5.png)
Customization
Winding 1 connection (~1) — connection of the primary winding (terminals ABC)
Yg (default) | Y | Yn | Delta (D1) | Delta (D3)
Connection of the primary winding.
Winding 2 connection (~2) — connection of the secondary winding (terminals abc)
Yg (default) | Y | Yn | Delta (D1) | Delta (D3)
Connecting the secondary winding.
Parameters
Units — pass unit sy\$
\$ pu (default) | SI
Specify the units used to enter the parameters of this block. Choose pu to use the units of measurement. Choose SI to use SI units. Changing the Units parameter from pu in SI or from SI in pu automatically converts the parameters displayed in the block mask. The conversion to units is performed based on the rated transformer power Pn, the rated frequency fn and the rated voltage Vn in the Vrms windings.
Nominal power and frequency — nominal power and frequency
[250e6 , 50] (default)
The rated power and the rated frequency of the transformer.
Dependencies
The nominal parameters do not affect the transformer model if the Units parameter is set to SI.
Winding 1 parameters — the rate of change of current when measuring iRM
[735e3 , 0.002 , 0.08] (default) | [7.35e+05 4.3218 0.45856]
Rated phase voltage in RMS volts, resistance and dissipation inductance for the primary winding.
Dependencies
By default [735e3 , 0.002 , 0.08] if the Units parameter has the value pu, and [7.35e+05 4.3218 0.45856] if the Units parameter has the value SI.
Winding 2 parameters — parameterization of recovery time
[315e3 , 0.002 , 0.08] (default) | [3.15e+05 0.7938 0.084225]
Rated phase voltage in volts RMS, resistance and dissipation inductance for winding 2.
Dependencies
By default [315e3 , 0.002 , 0.08] if the Units parameter has the value pu, and [3.15e+05 0.7938 0.084225] if the Units parameter has the value SI.
Magnetization resistance Rm — magnetization resistance Rm
500 (by default) | 1,0805e+06
Magnetization resistance .
Dependencies
By default 500 if the Units parameter has the value pu, and 1,0805e+06 if the Units parameter has the value SI.
Magnetization induction Lm — magnetization inductance Lm
500 (by default) | 2866
Magnetization inductance for a core with an unstoppable resistance.
Dependencies
The Magnetization induction parameter not used if the Saturated core checkbox is selected.
By default 500 if the Units parameter has the value pu, and 2866 if the Units parameter has the value SI.