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 ...
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7.2. ANALYZATION OF THE DISTURBANCES 58<br />
Figure 7.4: Some voltage signals with power quality<br />
disturbances<br />
7.2.3 Generalizing the classification pattern<br />
The analysis <strong>of</strong> the capaci<strong>to</strong>r bank switching, shown in the previous section, can be<br />
exp<strong>and</strong>ed <strong>to</strong> other power quality disturbances. Figure 7.4(a) shows the perfect fun-<br />
damental voltage waveform <strong>and</strong> is used as a reference for the other seven voltage<br />
waveforms. Figures 7.4(b) <strong>to</strong> (h) show seven voltage waveforms that represent typ-<br />
ical power quality disturbances: a short-circuit fault 7.4(b), a notching dis<strong>to</strong>rtion 7.4(c),<br />
a harmonic dis<strong>to</strong>rtion 7.4(d), a voltage sag 7.4(e), a voltage swell 7.4(f), a capaci<strong>to</strong>r bank<br />
switching 7.4(g) <strong>and</strong> a inductive-resistive load switching 7.4(h). All this voltage wave-<br />
forms leads <strong>to</strong> characteristic deviations <strong>of</strong> energy distribution pattern. So the five steps<br />
described above were used <strong>to</strong> get these pattern. The pattern for this seven voltage<br />
waveforms are shown in figure 7.5. Figure 7.5(a) does not show any deviation because<br />
it refers exactly <strong>to</strong> the pure sinusoidal <strong>and</strong> there is no deviation. This pattern can be<br />
calculated for each disturbance which can occur in power networks. Of course these<br />
pattern are not always exactly the same, but in a small range.