Development Of Network Based Power Quality Monitoring System

In recent years, with the expansion of the power grid and the rapid developmentof power electronics technology, a large number of loads appear in the modern powergrid, for example, non-linear, impulse and rectifier. These loads will pollute the powergrid and reduce the reliability of power supply. At the same time, some sensitive loadsrequest the power grid to improve power quality. It’s as a commodity that power isdirectly related to interests between the suppliers of power and the consumers.Establishing power quality monitoring system and monitoring real-time status ofpower quality can offer the basis for the power quality improvement and management.Combining theory and practice, a network power quality monitoring system isdesigned and developed in this paper. The layered and distributed architecture hasbeen used in the system, which has included the data acquisition devices, Datatransmission unit, Database sever, Web server and Web application server. The voltageand current signal are collected in real time by data acquisition devices installed inpower plants and substations. These data are processed and analyzed by themonitoring software and then the information of power grid is achieved, which arefrequency deviation, voltage deviation, voltage fluctuation and flicker, harmonic,three-phase unbalance and disturbance waveform data. The information is transmittedto the database server and Web server by the data transmission unit. The power qualityinformation is stored and released by the database server and Web server, whichprovides data support for power quality comprehensive evaluation, failure analysis,voltage disturbance classification and so on.The monitoring stations are integrated in the power grid by database technology,web technology and communication technology, in order to achieve networkmonitoring of power quality. Web services have features of cross-boundary,cross-platform, fast and convenient transmission of information. It allows usersanywhere to access the PQMS by Web browser, inquire PQ information in Web siteand share the information.