Symmetrical Components Extraction in Natural abc Frame

Question

Hello Everyone,

I have been trying to decompose symmetrical components in natural abc form into positive, negative and zero sequences using Fortescue's or Lyon's theory. Unfortunately, I am new to Plexim. Thus I could not achieve the objectives. Could anyone able to help me and make my simulation as attached work properly, please? Your input is greatly appreciated!

Regards

Noor

Answer 1

Hello Nur,

Signals in PLECS can only be real values. Symmetrical component decomposition is a phasor / complex number operation.  You can use the "Fourier Transform" block from the library to convert a sequence of real-values into the magnitude and phase of the specified harmonic.

Attached are two models that show different approaches to symmetrical component extraction.  The "sequence_cscript" example is more conventional in that it takes the Fourier Transform of the real-valued inputs and then performs the numerical decomposition using a C-Script block.  The "sequence_dq" example uses the forward and reverse synchronous reference frames to extract the sequence components and then uses a Fourier Transform as the last step to show the magnitude and angle of the components.  The reference frame approach is generally more robust in the presence of extreme background harmonics.

Regards,

Bryan

Comments

Hi Bryan,

Thank you so much for your brilliant answer and example! Its extremely useful not only for me but also other forum members.

Best regards,

Nur