Research On Power Quality Algorithm And Power Quality Monitoring And Management System

Power quality has become a major concern of the electric power industryproblems, quality of the electric energy directly affects the power user operationstability and continuity, and further more affects the personal and property safety.Power quality problems mainly refer to the abnormal phenomena of electricenergy due to various causes in the process of transmission, including thewaveform distortion of the voltage and current and the frequency fluctuation ofthe alternating current and so on. Several power quality algorithms are discussedin this paper and the advantages and disadvantages of these algorithms arecompared, then PRONY algorithm and S transform algorithm are selected astools to analyze data collected from phasor measurement unit, and build a powerquality monitoring platform based on the B/S mode to visualize the collecteddata and analyzed power quality indices. The main research contents of thispaper are as follows:(1) This paper firstly introduces the research background and status ofpower quality, illustrates the principle of the phasor measurement unit and thefunction of the global positioning system, and then describes the power qualityindices briefly; the advantages and disadvantages of several common power quality algorithms are compared and analyzed, then determining using thePRONY algorithm and S transform algorithm to analyze the power qualityindices.(2) A lot of materials about data communication are researched and theserial communication technology and general packet radio service (GPRS)technology are studied in depth, then the multi-thread technology is used towrite the data receiving and storage program based on serial communication andGPRS Technology on the host computer to collect and restore the data uploadedby PMU.(3) Power quality wide-area measurement system is designed based onBrowser/Server mode and visual studio2010. The database and its accessmethod are chosen firstly before the system design, data analysis have becomerealized through C Sharp and Matlab hybrid programming, that is the dot m file,namely solving power quality parameters by Matlab function, theimplementation of data management and real-time monitoring have been solvedby SQL2005database and threading. The data image display have beenachieved by Zedgraph widget, the information of sub station and historical datahave been obtained from Web data server by structure query language, the curvedisplay of historical data analysis have been shown by ZedgraphWeb control,the real-time data have been obtained by socket network programmingtechnology and the real-time display of grid frequency have been achieved byAjax technology. Thus it realizes data acquisition, data analysis, data management, and data real-time monitoring function in the host computer.This paper have provided a theoretical research on power quality algorithmand power quality wide-area measurement system, and further application havebeen made in the research combined with practice, it has a certain practicalsignificance influence on the development of power quality wide-areameasurement system. The database operation and data acquisition on the hostcomputer is realized by utilizing ADO technology and socket networkprogramming technology respectively.