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

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7.2. ANALYZATION OF THE DISTURBANCES 57 Figure 7.3: Distribution of energy in 10 wavelet coefficient levels 7.2.2 Identifying the disturbance In order to try to identify the type of disturbance of this voltage signal, the step 3 (which was explained in chapter 7.1 has to be work out. In this step, through equation 7.1, the energy concentrated in 10 wavelet coefficient levels is calculated and plotted. The results are in figure 7.3(a). The 7th level holds the biggest part of the signal energy. The 6th level keeps also an important parcel of it. The remaining levels practically do not add any important parcel to the signal energy. After this, in step 4, the fundamental component of figure ??(a) voltage is evaluated as well as the corresponding energy distribution. This is illustrated in figure 7.3(b). After this, if a visual comparison was made between figures 7.3(a) and (b), no important differences could be observed. However, these figures are not equal. In order to spot these differences, the equation 7.2 is used. This equation allows the calculation of the deviation between the energy distributions of the signal in study and its corresponding fundamental sinusoidal wave signal, at each wavelet decomposition level. The result of this is the deviation curve, illustrated in figure . This curve shows the deviations of the signal with disturbance from the corresponding pure sinusoidal one. The curve of figure 7.3(c) is within the "pattern" for capacitor bank switching.
7.2. ANALYZATION OF THE DISTURBANCES 58 Figure 7.4: Some voltage signals with power quality disturbances 7.2.3 Generalizing the classification pattern The analysis of the capacitor bank switching, shown in the previous section, can be expanded to other power quality disturbances. Figure 7.4(a) shows the perfect fundamental voltage waveform and is used as a reference for the other seven voltage waveforms. Figures 7.4(b) to (h) show seven voltage waveforms that represent typ- ical power quality disturbances: a short-circuit fault 7.4(b), a notching distortion 7.4(c), a harmonic distortion 7.4(d), a voltage sag 7.4(e), a voltage swell 7.4(f), a capacitor bank switching 7.4(g) and a inductive-resistive load switching 7.4(h). All this voltage waveforms leads to characteristic deviations of energy distribution pattern. So the five steps described above were used to get these pattern. The pattern for this seven voltage waveforms are shown in figure 7.5. Figure 7.5(a) does not show any deviation because it refers exactly to the pure sinusoidal and there is no deviation. This pattern can be calculated for each disturbance which can occur in power networks. Of course these pattern are not always exactly the same, but in a small range.
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Development of a wavelet-based algo
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Eidesstattliche Versicherung Ich ve
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2.5.2 Software modules . . . . . .
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Chapter 1 Introduction Electrical p
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Chapter 2 Power Quality Recorder Si
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2.2. FUNCTIONS 5 2.2.2 Power data r
Page 14 and 15: 2.3. INTERFACES 7 The binary inputs
Page 16 and 17: 2.4. OPERATION MODES 9 cessed. Figu
Page 18 and 19: 2.5. SOFTWARE (OSCOP P) 11 2.5.2 So
Page 20 and 21: 2.5. SOFTWARE (OSCOP P) 13 Figure 2
Page 22 and 23: 3.1. SIMEAS R CONFIGURATION 15 •
Page 24 and 25: 3.2. LABORATORY USE 17 Then the SIM
Page 26 and 27: 4.2. SOURCES OF TRANSIENT DATA 19 c
Page 28 and 29: 4.3. FILES FOR DATA EXCHANGE 21 4.3
Page 30 and 31: 4.3. FILES FOR DATA EXCHANGE 23 p=
Page 32 and 33: 4.3. FILES FOR DATA EXCHANGE 25 ft
Page 34 and 35: 4.4. DIFFERENCES BETWEEN THE 1991
Page 36 and 37: Figure 5.1: Structure chart of the
Page 38 and 39: 5.1. DATA STRUCTURE OF DATA STORAGE
Page 40 and 41: Chapter 6 Wavelets 6.1 Introduction
Page 42 and 43: 6.2. BASIC IDEAS OF THE WAVELET TRA
Page 60 and 61: Chapter 7 Algorithm to determine ce
Page 62 and 63: 7.2. ANALYZATION OF THE DISTURBANCE
Page 66 and 67: 7.2. ANALYZATION OF THE DISTURBANCE
Page 68 and 69: 7.3. MATLAB IMPLEMENTATION 61 7.3.2
Page 70 and 71: Chapter 8 Conclusion and Look-Out T
Page 72 and 73: LIST OF FIGURES 65 6.8 Scale level
Page 74 and 75: Bibliography [1] Ronald W. Schafer
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