Monitoring And Analyzing Of Transient Power Quality Based On Virtual Instruments

With the widely using of large power electronics, and the rapid increasing of devices sensitive to power quality, transient power quality problems such as voltage sag, voltage swell and short-time interruption have been paid more and more attention to by power utility and customers. In this paper, improved recursive wavelet transformation is used to detect transient disturbance, determine the moment the disturbance happened and the endure time of disturbance; wavelet's energy distribution curve is used to identify transient PQ of different type; the change rule of RMS is used to determine the disturbing source of voltage sag; the method to determine the direction of disturbing source is proposed. By using virtual instrument developing software LabVIEW, a detection and analysis system of transient PQ is set up on PC, through which the detection, identification of transient PQ, finding out the corresponding cause and source are realized.