Research On Multi-Function Power Quality Monitoring Devices For Power Distribution Terminal In Smart Grid

The multi-function electric energy monitoring devices in the terminal ofsmart grid distribution system is a new pattern o f smart meter based on theoriginal design，which can also analysis the power quality. this smart grid canbe used in the factory and research institution where requires highly powerquality.The smart grid is terminal unit of smart grid, contact the us ers to powersector. By the use of new technology, the smart grid can monitor theconsumption,analysis the harmonic, and communicate ovonicly. With thedevelop of economy, there are many power electronic device used in powersystem and reduce the power quality, which become a hot spot. To improvethe power quality, the information about the power quality must be collected,and fault location. Feature extraction classification and recognition isnecessary. based on this, the paper research the detection and recognitionmethod about disturbance of the power quality.Firstly, the calculation method of power quality index and basic detectiontheory were introduced, and different analysis method about power qualitywas discussed, as well as the advancement. Sin ce the wavelet transform hasnice time-frequency localization characteristics, the signal’s singularity can becharacterizated by the wavelet transform modulus maxima,so the wavelettransform can be used in transient power quality disturbance.The Pronymethod has nice frequency resolution, can separate the each frequencyaccurately,because of this,it’s also be adopt.Secondly, the hardware and software design was discussed. Basic on therequirement of instantaneous and efficience,the double-CPU structure,that is,DSP and MCU iwas adopt.DSP was used for data operation,and MCU for datamanagement,that is, the function of preserve, display and transmit.Bymeans of simulation and test, the system basically meet the designrequirements.Lastly, the simulation test indicate that using the wavelet transform detectmutation signal can not only effectively discriminate the transient andsteady information of power quality,but also measure the start-stop momentof the transient disturbance accurately, when the disturbance occur. As to Prony, the simulation test indicate that in case of tiny noise, it can separateeach frequency accurately, and confirm the characteristic parameter of eachfrequency.