| In recent years, the power grid and its load structure has undergone great changes. In particular, the interference of a huge amount of impact, non-linear electric load has brought voltage waveform distortion, voltage fluctuations and a series of power quality problems. Along with the propulsion of electric power reformation and release the purchase and sale of electricity business, power sector not only need to meet user’s growing demand for power capacity, but also ensure high power quality. Therefore, to develop an online power quality monitoring system(PQMS) which is high precision, low cost, easy to use and can synthesize the characteristics of the distribution which has nodes in large quantity and area is of great significance to ensure the power grid and electrical equipment operation safe and economical.Through a large number of scientific literature at home and abroad, the article talks on research background、significance and the development situation of power quality monitoring device, research and analysis the new calculation methods of power quality parameters. The article compares the existing architecture form of such monitoring systems, analyzes the advantages and disadvantages of each, a PQMS is designed by using DSP, MCU, GPRS and Lab VIEW. This monitoring system has the advantages of low cost, high precision, strong ability in operation, suitable for online and offline monitoring, is not subject to regional and broadband network conditions, etc.In the aspect of hardware design, the article has designed a DSP system based on TMS320F28335 and an MCU system based on C8051F340 as the core of operation and control of the system. And on this basis, it has designed the sensor unit, sampling trigger unit, analog-to-digital conversion unit, GPRS unit, SD card unit, etc. All PCBs of these units were designed and realized.In software, the program of DSP and MCU for control, operation, communications is developed using C language in the development environment of CCS v4.12 and Keil v4. And a humanized human-computer interface and anlysis software is developed based on the Lab VIEW platform. It has realized the functions of real-time analysis, display, storage, the event log, remote network publishing, etc.Experimental results proved that the design project was effective and rational, and shown that system functions and indicators have achieved the relevant national standards and design goals proposed in this paper. |
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