FFT for Harmonic Analysis

Hello everybody, If anyone can help me in the following it would be great. In the simulink window, I have a power system designed with wind turbines in it. I'm supposed to study the harmonic analysis on it using FFT from the powergui environment block. I measured the voltage and the current output of the wind turbine which is supposed to have a huge amount of harmonic contents. My problem is, whenever I change the start time of the FFT window, the THD (Total harmonic distortion factor) changes. So anyone has an idea what is the suitable time to obtain correct THD, or even how should I select this time??? Any ideas...?!!

Answer 1

[Madhu]

Hi

The same problem i faced in my experience and there i faced this problem because i havnt given any reference or base values to wind. When you directly connect a wind turbine to generator with out any reference value, at each and every simulation, level of harmonics may change. So you should give a reference value to the wind turbine and if you dont want to compare the results with the reference value, you can keep a constant block.

Try doing this and hope this helps you

[Ayman Esmat]

Thank you very much for your help.

But what do you mean by a reference value to wind? Do you mean the speed?

Because, I have a constant block for the wind speed.

[Abdurrahman]

PLS HELP ME MY FFT ANALYSIS IS SHOWING NO SAVED FILE UNDER STRUCTURE THAT IS 'EMPTY' EVERY THINGS HOW CAN I SAVE MY WORK SO THAT I SEE IT UNDER AVAILABLE SIGNAL