Study On The Voltage Disturbance Identification And Detection Of Distribution Network Based On Wavelet Transform

According to the large scale application of sensitive devices such as digital system, power electronics devices, adjustable speed drivers, programmable logic controller, and the increasing improvement of industrial automation and complexity of power network, the economic loss caused by voltage sag problem is seriously increasing. Short-circuit fault occur in high frequency on distribution feeder and the affected area is broad. Voltage sag is now a stability factor of power supplies and has been noticed by power supplier, customer, and equipment manufacturer. It is therefore extremely meaningful and practically useful to pay much attention to analysis, identification and monitoring of voltage sag. The article analyzes distribution network voltage disturbance, Based on wavelet transform, including the following:Firstly, the paper discusses the principle of wavelet multi-resolution signal decomposition and its implementation using the filter, puts forward power quality transient disturbance detection method based on the fast algorithm of wavelet power, transient oscillation, transient pulse analysis of power quality disturbance detection and time-frequency simulation results are given, the wavelet transform into electrical energy provided a new effective method for quality inspection.Secondly, According to the characteristics of voltage sag events will interference source is divided into fault classes, such as switching of transformer.Using jump point location, size, and direction of the effective value voltage waveform of base wave and the graded information to describe the voltage sag events, characteristic index can be obtained by B spline dyadic wavelet transform. how to use wavelet transform to accurately distinguish voltage sag interference source and its direction are analyzed in detail.results show that:voltage sag waveforms and event characteristics which caused by different disturbance sources are different, these features are particularly evident on the valid value of fundamental-wave, therefore, the description, identification and evaluation of voltage sag events can be achieved by using these features.Thirdly, proposed in this paper based on the wavelet transform of the voltage flicker signal detecting method, and has good localization characteristic in both time domain and frequency domain, not only in time domain or in the frequency domain but only in wavelet transform domain for signal detection, and can detect the voltage fluctuation and flicker signal in time, frequency and amplitude of mutation, very suitable for transient voltage fluctuation and flicker signal detection.Fourthly, Based on analysis of the characteristics of wavelet transform to detection of the harmonic, a control algorithm is proposed for active power filter based on wavelet transform. This paper use MATLAB software to establish the simulation model and Simulation of the proposed compensation algorithm.