Chen Chunling

Power quality disturbances classification Based on multi-class classification SVM

this paper used the multi-class classification for support vector machine and combined with the good amplitude-frequency characteristic of fourier transform,the good time-frequency characteristics of wavelet transform and the excellent statistical learning ability of support vector machine to make the classification and recognition to the disturbances of power quality. Mathematical modeling for the 8 kinds of common power quality disturbances, namely voltage swell, voltage sag, voltage interruption, harmonic, voltage fluctuation, transient oscillation , transient pulse and frequency deviation, and then use fourier transform and wavelet transform to extract the characteristics of the waveform of the generated samples, and input the characteristic value to the osu_svm and do the quality disturbances Multi-class Classification. The example shows that this method has a high recognition accuracy, a few training samples and training time is short, a good real-time performance, and is not sensitive to noise, etc. It is an effective method for Power quality disturbances classification.

Analysis of power quality transient disturbance signal based on wavelet packet transform

Transient power quality problems is the salient problem in todays power quality problems. And its detection is the precondition of monitoring and restraining. Wavelet package transform with better time frequency resolution is developed on the wavelet transform. The signal is decomposed on the wavelet package plane and the characteristic weights of signal can be achieved using available information. Through to the transient signal of voltage sag, the voltage swell, voltage interrupt, transient oscillation for analysis results show that wavelet package transform is also useful in analyzing the transient power quality.

Application of virtual instrument techonoly in electric courses teaching

This paper analyzed the problems existed in practice teaching process of electric courses and put forward a new view which is to apply virtual instrument (VI) technology in theses courses. On the basis of a simple instruction for labVIEWs VI design function, an instance which designed by labVIEW to emulate and detect harmonic signals was described in detail. The instance has been used in the course of power quality and obtained a good result. More and more instances were designed based VI and used in electric courses, it can promote the combination between theory and practice and improve teaching level of these courses.