The Research On Long-Distance Power Quality Monitoring And Active Power Filter

Electric Power is the most important energy in modern society. Electric power plays important roles in industry production and our lives. The stability of the power system and the quality of electric power affect the development of national economy. More and more power electronic equipments are used in the power system. They are making a lot of power quality problem when they improve productivity. These problems not only harm the electric equipments, but also threaten stability of the power system. It is very significant to research on improving power quality. In order to improve power quality, this paper focuses on long-distant detecting of power system and active power filter technology. It consists of following work.A long-distant power quality detecting system based on Internet is designed in this paper in order to have a thorough grasp of power quality. This detecting system transports sampling data of power system node to center server by FTP protocol. This system can synthetically analyze power quality of the power system, and it is a powerful tool for improving power quality.A broad bandwidth is needed for transporting a mass of sampling data directly, and that restricts the application of the long-distant power quality detecting system. A data compress method based on DCT transform has been proposed in order to used the detecting system in a narrow bandwidth network. This method can improve the data communication efficiency, and deduce the memory room.The active power filter is novel equipment for improving power quality. It can compensate the harmonics, reactive power, three-phase asymmetry simultaneously. It is important for active power filter to detect the distorting current accurately. A precision detection method has been proposed in this paper. This method can detect harmonics, fundamental active current and reactive current in the case of unsymmetrical three-phase voltage...