The Application Of Wavelets To The Monitoring System Of Power Quality

Power quality monitoring is a key part for the control of power quality. It is also a necessary condition to ensure good power supply. The establishing of power quality monitoring system can not only get the targets of power quality during the running of the system in detail and supervise polluted object, but also provide evidence for improving and renovating the power quality. Static power quality and dynamic power quality are also concerned today. The idea to develop a comprehensive monitoring system of power quality based on wavelet is brought forward. It monitors not only static power quality but also dynamic power such as voltage sag, swell and momentary interrupt.The problem of power quality has been researched from three aspects in this paper.1. With the capability of wavelet to detect disturbed points, wavelet is used to analyze the dynamic power quality. In this paper the signals of swell, sage, momentary interrupt are simulated with the methods of wavelet, and the simulations show the method of wavelet can fix on the positions of the voltage break.2. In addition, wavelet packet method is used to analyze static power quality. In this paper the voltage signal with harmonies is simulated with the methods of wavelet packet. And as a result, the wavelet packet method has a good performance in high-frequency. It's proved that all of the harmonies signal can be picked up by using the wavelet packet method. And it has a good performance on analyzing the harmonies signal.3. With the technology of GPRS and J2EE, the monitoring system of power quality is developed. It's used to monitor and analyze the power quality data in real time and in long distance. Compared with other systems, the developed system has the advantage of long-distance monitoring, easy maintenance and easy operation etc. This system has been accepted by state grid. And it has been running in shanghai power.