Research On Power Quality Monitoring System For Ship Power Grid

Nowadays,with the development of electronic technology,a large number of powerelectronic device and nonlinear load applied to the ship power system.To improve theperformance of the ship at the same time,also cause serious pollution to the shippower,produce adverse influence to the electrical equipment and threat the economicproperty safety seriously.Therefore,to monitor and analyse the power quality real-time,ens-ure the safe operation of the power system,has become the focus of attention at the homeand abroad.This paper introduces a ship power quality monitor device based on DSP(digital signalprocessor) that is the core,can realize real-time data display.Because of DSP with strong dataprocessing ability,can be used to complete all electric power data index collection andcalculation.At the same time,with large capacity storage space can provides a strongfoundation for the following data analysis.First,review the reason that the ship power quality produce,discuse the presentdevelopment in domestic and foreign and the existing monitor problem in powerquality;Second,tells more detaily the power quality index and related standards;On thisbasis,research the related power quality detection algorithm and make the simulationanalysis;Then introduces the monitoring system hardware and software structure designdetaily.Finally,overall debugging in the related experiment and error analysis of the system.The device adopts TMS320F2812as the core of the system chip,and can realize themultiple power quality on-line measurement.In order to guarantee the system performance,this theory made the related technology research:in order to track the frequency automaticl-y,the hardware phase locked loop technique has been used in the hardware,prevent themonitoring indicators from system frequency change,prevent the spectrum leakage.In thesignal conditioning circuit,we use the linear light coupling to realize the isolation of analogand digital circuit.In software,we use the methods of combing FIR digital filter and harwarefilter to prevent spectrum aliasing in the process of sampling,and improve the accuracy ofthe singal sampling effectively.The method based on Mallat algorithm of the waveletanalysis to the harmonic detection,which overcome the Fourier analysis localized in thefrequency domain and time domain in no local defects,which is suitable for analyzing stationary signal,it is also suitable for non-stationary signal analysis and improve theaccuracy of the calculation.In order to adapt to the ship environment communicationrequirements better,the device offers a variety of communication interface methods to reali-ze the real-time monitoring data transmission and timing extraction storage records,realizeinteractive data with remote electric energy quality management center.The experimental results show that the monitoring system has high precision and acc-uracy,the power quality monitoring indexs conform to the national standard,communicatio-n, good stability and strong application prospect.