Research On Web-based Power Quality Management System

With the rapid growth of economics, power quality issue has increasingly captured considerable attention from both utility companies and their customers. On one hand, with the increase of nonlinear loads, there are more and more factors that will bring challenge on the power quality, for instance the progress on power electronics appliance and its implementation in industry and transportation companies. On the other hand, people have higher request on the power quality and reliability of power system because more complex, rigid and power quality-sensitive appliance is widely used. At the same time, with the rapid development of electric power industry, stabile power quality issues, such as voltage fluctuation and flicker, frequency fluctuation, harmonics, have increasingly captured considerable attention from utility companies and their customers. Transient power quality issues have been becoming extrusive, such as voltage well, voltage sag and voltage interruption, and bring customers amount of loss. Because more and more customers are concerned about power quality issues, it is necessary to establish a power quality management network under the situation.As Internet is growing rapidly, it becomes a popular issue in computer world, especially because of its open architecture. Power quality management will be improved greatly if Internet is introduced. Due to the popularity of Web skill and the trend of network, communication, the application of Web technology in power quality management is studied in this paper.Under the network environment, the research of this thesis focuses on Web-based power quality management system. It takes advantages of both "Fat client" scheme and "Thin Client" scheme to get the best solution of composite power quality management system. Through assigning tasks to client and server rationally, the client and server can make the better use of their processing ability to achieve the goal that the system can have the best performance with the least resource occupied by data and application program. This paper explains architecture of each level with relevant technology and details of its implementation.This system applies Active Server Pages (ASP) technique and other related Web techniques to carry out composite data query based on the database with large data size and complicated data structure. Such techniques as data analysis, control and processing are integrated with the information query and distribution system using Web technique, taking the consideration of application's security and the system's performance.Design of this solution is implemented according to users' need directly. Users need download corresponding function components and save them in client workstation permanently when they want to use this system through Internet for the first time. This mechanism is so-called "download once, use permanently". It can help to reduce the occupation rate of network resource. The efficiency of the network use is fully represented. In the ASP files, the connection with database is realized by ADO. Based on the information about query object, time, and columns provided by users from the pages, self-contained SQL commands are created to operate on corresponding database tables and views. So that users can get all needed figures and statistics report forms exactly and rapidly with the guidance of friendly user interface.Finally, this paper narrates the setting-up procedures of the server in this system. Web server use ASP technology, set up an integrated server environment through IIS (Internet Information Serves) and MTS (Microsoft Transaction Server), use ADO to visit target's database. Programs (such as power quality monitoring data processing, electric grid relevant parameter management etc) are developed through VB inapplied server. The focal point of whole server system is visiting database and monitoring data processing, guarantee the integrality, dependability and security of data visiting.The power quality management system set up in this paper makes greater progress compared wit...