Development Of Coal Mining Power Quality Analysis System

Electricity is the main power source of coal mine. With introduction oflarge power electronic devices, the coal power quality problem become moreand more serious. However, because automation level of the coal mine isincreasing constantly, various automatic detection systems are introduced,which are sensitive to power quality problems. Thus, the higher power quality isrequired. Nowadays, coal mine accidents caused by power quality areincreasing, so comprehensive monitoring of coal power quality is very urgentand necessary.In this paper, the segmented FFT and wavelet packet transform wereapplied to detect fluctuation harmonics. The segmented FFT detection modeland wavelet packet transform program were developmented, which wereapplied to the analysis of fluctuation harmonics. Simuliation results showed thatthe proposed methods can give the trends of harmonic amplitude with time anddetermine occurrence time of harmonic. In addition, simulation model of twomethods were developed in MATLAB, and simulation results showed thatpresented methods were viable. The relationship between the flux fluctuationand flicker was established, which used to discuss the defect that IECflickermeter monitored flicker caused by interharmonics. Based on this, themethod based on resampling and peak detection was proposed, which used todectect flicker caused between detection. The simulation model of new methodwas established in MATLAB, and this method is effective by simulation results.In the paper, the coal mine power quality system was achieved based onLabVIEW platform. The acquisition circuit was designed, and the selection andconfiguration of data acquisition card was completed; the software of analysissystem was completed, subroutines of data acquisition, basic electrical parameters, voltage deviation, frequency deviation, three phase unbalance,harmonic analysis, inter-harmonic analysis, voltage fluctuations and flicker,voltage sag, data storage were programmed. On the basis, the coal mine powerquality system was designed by calling each subroutine. In addition, a goodinteractive interface was designed.Finally, the effectiveness and accuracy of power quality analysis systemwere validated. A virtual signal generator was developed on LabVIEW platform,which was as the input signal of power analysis system. Compare measurementresult of analysis system with theory result, and the rerults showed that thedetection accuracy of the system designed to meet performance indicators.