Development of a wavelet-based algorithm to detect and determine ...

7.3. MATLAB IMPLEMENTATION 60
Figure 7.6: Structure chart of the program module
which calculates the reference energy
7.3 MATLAB implementation
7.3.1 Program modules
The theory in the section above is now implemented in a Matlab program. This pro-
gram is splitted into three small modules. The first module, which imports the distur-
bance recordings into Matlab was already described in chapter 5. Two versions of this
module are able to import disturbances recorded in Comtrade format (see chapter 4)
as well as disturbances stored in MATLAB [10].
The second module has to be run after the import of the disturbance data and calculates
the reference signal, the multiple wavelet decomposition and the energy distribution
over ten wavelet decomposition levels. This energy distribution is used as the reference
energy distribution for the second module to identify the disturbance. Figure 7.6 shows
the structure chart of this module.
The third small program calculates the disturbed energy distribution of the signal in
study and the deviation from the reference energy distribution. The result is the devi-
ation of energy distribution pattern. The function of this program is illustrated in the
structure chart in figure 7.7. The shadowed part of the program module is finished but
not tested. It can be tested if the pattern are calculated for 50Hz and the corresponding
sampling frequency.