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

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2.2. FUNCTIONS 5 2.2.2 Power data recorder The power data recorder functionality stores the signals continuously. The averaging time is freely configurable. The mean values are determined from the calculated r.m.s. values (which are calculated every cycle). Different averaging times can be configured for the electrical values. The following electrical measurements are stored and determined by the evaluation program: • Voltage U1, U2, U3, U4 • Current I1, I2, I3, I4 Note: Depending on the type of power network and connec- tion, either the phase voltages or the phase-to-ground voltages are recorded. • Active power P1, P2, P3, P4 • Reactive power Q1, Q2, Q3, Q4 • Power factor cos phi 1, 2, 3 • Frequency f • Positive-sequence system • Negative-sequence system • Weighted and unweighted distortion factor • Harmonics (max. 5 selected for an averaging time up to 10s) • Harmonics (50 for averaging times of 10s upwards) • DC signals when the DDAU is used This function allows the feeders to be continously monitord and an analysis of the network quality can be performed.
2.2. FUNCTIONS 6 2.2.3 Power and frequency recorder This functionality is used to record the load conditions before, during and after a fault occurs. Power swinging within the power network is recorded over a long period of time. The length of the recording time depends on the configuration of the period for which a mean value is estimated. The principle of operation is similar to the fault recording mode, however, the signals are determined every cycle (e.g. every 20ms at 50Hz frequency) and stored depending on the configuration. The signals are stored at an interval between 1 and 250 cycles. If, e.g., 100 cycles is configured, the average of the values is determined over this period. The frequency channel has an accuracy of ± 1mHz. The recording can be initiated using the start selectors. The trigger is derived by comparing the current value with the previously determined value. The maximum pre-fault time is, e.g., 40 minutes for an averaging time of 250 cycles. The power and frequency progression is recorded for up to 2 hours, independent of the averaging. If the averaging time is set to one cycle, then 10s of pre-fault are available. The power and frequency recorder is used especially for recording the primary control in power stations and swinging turbines in electrical power systems. The frequency gradient ∆f/∆t reacts if a power station is disconnected from the network, or a large change in the network power occurs. Since all the inputs are recorded in parallel, the user can generate a power balance, for an infeed point in the switchgear. This function is automated in the OSCOP P program package. 2.2.4 Event recorder The binary inputs are sampled at 2kHz (0,5ms). State changes are written with a real time of 1ms into the storage. For each of the 16 binary inputs, 200 state changes can be stored within 1s. The entire storage can be freely configured. For 5 Mbytes of storage approximately 120.000 state changes can be stored.
Page 1 and 2: Development of a wavelet-based algo
Page 3 and 4: Eidesstattliche Versicherung Ich ve
Page 5 and 6: 2.5.2 Software modules . . . . . .
Page 8 and 9: Chapter 1 Introduction Electrical p
Page 10 and 11: Chapter 2 Power Quality Recorder Si
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
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Page 66 and 67:
Page 68 and 69:
7.3. MATLAB IMPLEMENTATION 61 7.3.2
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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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