Research And Implementation Of Power Quality Monitoring System Based On AHL NB-IoT

The power quality monitoring system for measuring voltage,power,voltage deviation and other parameters is very important for the operation of power supply system.Narrowband Internet of things NB-IoT is a new generation of Internet of things communication system whose basic layout is completed in 2020.The application of NB-IoT in power quality monitoring system is of great significance.The problems of power quality data acquisition accuracy and system communication stability involved in the system are worthy of in-depth study,the design method of the system is also worthy of discussion and practice.From the perspective of technology and science,this thesis presents a power quality monitoring system studies.The studies base on NB-IoT architecture among webpage,server,terminal,involve the accuracy assurance of electricity meter and the stability of system communication,and carry out effective practice.The main innovations and practical work are as follows.(1)For the problem of ensuring the measurement accuracy of electric meter,a low-cost and efficient passive calibration method without three-phase calibration source is proposed,and improved data measurement algorithms are designed.Passive calibration uses common single-phase AC voltage regulator,commercial electricity meter and other cheap equipment,combined with the specified power factor load and software algorithm to complete the electricity meter calibration,which overcomes active calibration’s shortcomings,such as expensive equipment,large volume and low application flexibility.The improved data measurement algorithms includes anti pulse interference average filtering algorithm based on threshold and fast Fourier transform algorithm based on metering chip,which improves the anti pulse interference performance of data acquisition process and enhances the response ability to spectrum leakage and fence effect.(2)For the possible communication instability in the multi-level communication process among terminal,cloud listening software,web page,an integrated communication stability guarantee measure with cloud listening software as the core,based on the data request of electricity meter terminal and web page as the observation point is proposed,which improves the overall stability of the system.(3)The thesis proposes a scheme of power quality monitoring system based on NB-IoT architecture after the above research.The sheme is designed according to the AHL NB-IoT architecture proposed by embedded system and Internet of things laboratory of Soochow University.The terminal software and hardware design,cloud listening software and web page software are designed and implemented.After laboratory test,repeated modification and continuous optimization,it has entered the small-scale test stage of the factory.The system has stable operation and good effect and has been highly recognized by the cooperative units.