Research And Application Of Power Quality Monitoring System In Full Index

With the continuous development and rapid change of national economy and technology,the characteristics of power grid,load structure and regulation technology is undergoing tremendous changes in China's power system in the 21st century,and all kinds of power quality problems keep emerging,from which the National smart grid strategy comes into being.However,in the smart grid system,the collection of home user information and power quality data is the most basic link.The traditional power quality analysis instrument application does not involve the family user with the shortcomings of high price,low precision,not portable,etc.,and most of the measuring instruments can't detect the transient disturbance phenomenon or the detection effect is low.Therefore,it is of great significance to develop a portable,low cost,full index,high intelligent power quality monitoring system on the basis of ensuring the measurement accuracy.Based on the above background,this thesis introduces measurement structure and analysis method of power quality parameters,improves the measurement of power grid frequency,makes a brief introduction on the change phenomenon of fast voltage change(new word appeared in IEC 61000-4-30:2015 but not defined in National standard)and its measurement method,and details Class A?S and B measurement set(cumulative time interval synchronization method)and harmonic aggregation algorithm.Then,the HHT algorithm and its improved methods are introduced in the detection and analysis of the transient power quality disturbance phenomenon to avoid the end effects as well as to ensure the accuracy of the measurement.It also builds a model of typical disturbance phenomenon and verifies its effectiveness by simulation.In the next part,the software and hardware design schemes based on DSP28335 are proposed,and their implementation processes are determined.The hardware design includes power supply module,signal acquisition module,main control module,memory module,and circuit design combining anti-interference design.At the same time,the anti aliasing filter is designed for variable sampling rate.The software design includes DSP main program,frequency measurement,A/D sampling and DMA transmission,complex sequence FFT data processing procedure and power computation procedure,locating and recording the transient disturbance phenomenon.At the same time,the embedded Bluetooth module communicates with mobile phone through the communication program,so as to realize the remote power quality of electrical equipment.Finally,through the analysis of an inverter output voltage instrument performance test data,found practical applications exist in the process of sampling rate and the matching problem of anti aliasing filter.Based on another arc furnace test case data analysis,the monitoring system has achieved the initial formulation of the portable,low cost,full index,high requirements of the intelligent monitoring system.But there are still some room for improvement.