Development of a wavelet-based algorithm to detect and determine ...
Development of a wavelet-based algorithm to detect and determine ...
Development of a wavelet-based algorithm to detect and determine ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
7.3. MATLAB IMPLEMENTATION 60<br />
Figure 7.6: Structure chart <strong>of</strong> the program module<br />
which calculates the reference energy<br />
7.3 MATLAB implementation<br />
7.3.1 Program modules<br />
The theory in the section above is now implemented in a Matlab program. This pro-<br />
gram is splitted in<strong>to</strong> three small modules. The first module, which imports the distur-<br />
bance recordings in<strong>to</strong> Matlab was already described in chapter 5. Two versions <strong>of</strong> this<br />
module are able <strong>to</strong> import disturbances recorded in Comtrade format (see chapter 4)<br />
as well as disturbances s<strong>to</strong>red in MATLAB [10].<br />
The second module has <strong>to</strong> be run after the import <strong>of</strong> the disturbance data <strong>and</strong> calculates<br />
the reference signal, the multiple <strong>wavelet</strong> decomposition <strong>and</strong> the energy distribution<br />
over ten <strong>wavelet</strong> decomposition levels. This energy distribution is used as the reference<br />
energy distribution for the second module <strong>to</strong> identify the disturbance. Figure 7.6 shows<br />
the structure chart <strong>of</strong> this module.<br />
The third small program calculates the disturbed energy distribution <strong>of</strong> the signal in<br />
study <strong>and</strong> the deviation from the reference energy distribution. The result is the devi-<br />
ation <strong>of</strong> energy distribution pattern. The function <strong>of</strong> this program is illustrated in the<br />
structure chart in figure 7.7. The shadowed part <strong>of</strong> the program module is finished but<br />
not tested. It can be tested if the pattern are calculated for 50Hz <strong>and</strong> the corresponding<br />
sampling frequency.