Design And Implementation Of Power Quality Monitoring System Based On DSP

With the widespread application of high-power electronic equipments,all kinds of power quality problems caused by those have attracted high attention from researchers devoted in power field,and new technology which can improve power quality has recently become new hot spot in the research of power system.It can provide essential evidence for improving power quality,making out control measures and making appropriate technical parameters of control equipments by real-time monitoring,recording and analysis for power quality. So it is very significant to dosome research in power quality monitoing technology.This system combined DSP and CPLD chip to design a multi-function power quality monitoring instrument.It can measure three phase voltage,current and their harmonics,frequency,three disequilibrium,active power,reactive power,power factor etc.Except that it can record power off time and power on time.the data are saved every one minute.In addition, the system extends RS232/485 serial communication interface and GPRS,these interfaces can be convenient to develop database with upper computer and achieve remote monitor.Emphasis of the paper are laid on following:the principle and methods of power parameter measurement which bat around the FFT algorithm of harmonic analysis.Design of hardware,including least system of DSP,signal conditioning circuit,Frequency capture circuit,A/D transfer circuit,data saving circuit,the logic circuit in CPLD and communication interface circuit;DSP software design,including the programming of A/D transfer,the programming of FFT,the programming of keyboard and display service,the programming of data saving,the programming of communication interface ect;Finally, the paper shows hardware tests and software tests, analyses the result of the test.Research indicates the system has powerful function,its good performance such as accurate measurement,high measuring speed and good stability has got testified in many field application.So it has a wide prospect and practical values.