The Development Of The New Real Time Monitoring System Of Power Quality

According to the problem of electricity quality monitoring, this article has developed aset of monitoring system of the electricity quality, which is based on the technique ofembedded ARM and virtual instrument platform. It has realized the real time monitoring andthe analysis of Grid three phase, voltage/current, active power, reactive power, power factor,harmonic, three phase imbalance, flickering and other parameters. It can also help theComprehensive evaluation of power quality and the fault diagnosis. The followings are the mainresearch contents:1) The research of the method of how to calculate the power quality. It has analysed thecalculate principle of Power quality parameters in theory, and aim at the analysis of Powerharmonic, it has adopted the method of Least squares which is based on FFT, overcome thebarrier effect and spectral leakage, improve the calculation accuracy. What is more, it hasbeen examined in the environment of MATLAB, aim at the calculation of Flicker parameters,it has used the detection method of Flicker meter square which is recommended by the IEC,truthfully and accurately measure the short term flicker value.2) Hardware circuit design. It uses ARM7LPC2132as the Core processing chip, whichmakes full use of embedded function module. It has designed the power module,voltage/current transform module, signal acquisition/regulate module and communicationmodule. And in order to improve precision, it has made up the phase difference involtage/current transform module. For the convenience of remote monitoring, communicationmodule has adopted RS485.3) The software design and programming. Software module is made up by lower levelcomputer software and PC software. The lower lever computer software is based on theoperating system of C/OS. It is used for the collection of three phase voltage andcurrency and the calculation of the power quality. It means the analysis of power grid of theharmonic, the calculation of the unbalanced three phase, and the calculation of flicker parameters and so on. The PC soft ware has developed the man machine interactive softwareplatform which is based on the virtual instrument Lab Windows/CVI. It is used to completeall the power quality parameters of the display and storage, etc.In the end, the power quality monitoring system based on this scheme is compared withthe electricity parameter measurement modules of PDM800ACM, and the result shows thatthe testing precision of this system has reached what we want. What is more, the data isstable.