How to calculate right parameters for 3-phase two winding transformer Simscape Block?

Hi. I have issues with understanding and using parameters for a 3-phase two winding power transformer Simscape Block.

Three-phase linear nonideal wye- and delta-configurable two-winding transformer with saturation capability - MATLAB (mathworks.com)

I need to simulate the voltage drop and transformer power losses in a system with a 3-phase two winding transformer. I have transformer parameters from it's datasheet, such as rated power, rated primary and secondary voltages, rated currents. For estimation of impedances I have a short-circuit voltage, short-circuit power, no-load losses. From these I can calcualte winding impedances R1, R2, L1,L2. shunt magnetizing impedances Rm, Lm.

The problem is that I don't know where and how to provide these parameter in Simscape block. The impedances in the block are in power and not clear which applies to what. Does enyone have more clear description of block parameters and their relativity to phisical parameters?

[Umar]

Dear Artem,To input the transformer parameters into the Simscape block correctly, you need to understand how the block interprets these values. In Simscape, impedances are represented in per-unit values, which can be derived from the physical parameters you have. The rated power, voltages, currents, short-circuit data, and losses can be used to calculate the per-unit impedances (R1, R2, L1, L2, Rm, Lm) required by the Simscape block. Ensure that you convert these physical parameters into per-unit values before inputting them into the block. By aligning the calculated impedances with the block's requirements, you can accurately model the transformer behavior in your simulation. Hope that answers your question.

[Artem]

Hi Umar,

thanks for comment. The problem for me is that some block parameter descriptions are confusing: For example:

Primary winding resistance (pu) — Primary winding power loss

Per-unit power loss in the primary winding.

So is this parameter in resistance (pu) or power (pu)?

[Artem]

Also I would like to ask what is the recommended method to split the parameters into primary and secondary windings, if I have only total value. By transformer ratio?

[Umar]

Hi Artem,

Never mind, I was going to answer your questions but sounds like Milan apparently wanted to share his knowledge. Hope,he can provide a simulation example that he can shared with us.

Answer 1

[Milan Bansal]

Hi Artem

I understand that you are trying to configure a 3-phase two-winding power transformer in Simscape and are confused about the parameter descriptions and their application.

The reason behind the confusion is the use of per-unit (pu) values for parameters. Here are the steps to clarify and properly set up your transformer parameters:

1. Primary and Secondary Winding Resistances: Convert the given resistances to per-unit values based on the rated power and voltage.
2. Short-Circuit Parameters: Use the short-circuit voltage and power to estimate the winding impedances.
3. No-Load Losses: Use the no-load losses to determine the shunt magnetizing impedances.

Calculate Per-Unit Values:

• 
• 

Calculate the values for (R1, R2, L1, L2, Rm, Lm) using the given specification from the data sheet. Convert these values into per-unit (pu) using the above formulas.

In the Block Parameter, the fields in the "Main" section cab be entered from the datasheet.

For fields in the "Impedences" section, following values can be entered:

• Primary Winding Resistance (pu):
• Secondary Winding Resistance (pu):
• Select "include" for Leakage Reactance and enter the following values.
• Primary Leakage Reactance (pu):
• Secondary Leakage Reactance (pu):
• Select "include" for Magnetizing Resistance and enter the following value.
• Shunt Magnetizing Resistance (pu):
• Select "include" for Magnetizing Reactance and enter the following value.
• Shunt Magnetizing Inductance (pu):

Please refer to the documentation link to learn more about Two-Winding Transformer (Three-Phase)

https://www.mathworks.com/help/sps/ref/twowindingtransformerthreephase.html

Hope this helps!

[Umar]

Hi Milan,

Thanks for your contribution. I really appreciate it.

[Artem]

Thanks Milan

It is very useful.