SOPC Design Of Transient Power Quality Disturbances Detecting Based On Nios Ⅱ

With the rapid development of scientific technology and national economy, the factor thatcauses power quality problem unceasingly increases. So the power quality is put forward ahigher requirement. Power quality can be mainly classified into stable and transient powerquality. It is hard to acquire all kinds of information of the transient power quality disturbancesin time by the existing detection technology of power quality, because of variety and complexityof the disturbances. Therefore the detecting and analyzing of transient power qualitydisturbances is an important research subject about, and it has important realistic significance.Based on the research of both home and abroad, the detecting methods of a few familiartransient power quality disturbances is analyzed and studied in this paper. And a SOPC design oftransient Power quality disturbances detecting based on NIOS II is completed. add ADC,Wavelet, LCD, Keyboard, SPI etc Avalon peripheral interfacel to the SOPC. The simulationresults based on Modelsim show that the function of the designed SOPC meets the requirementsThe SOPC internal ADC sampling module acquires the accurate real-time grid data,Wavelet transform module detects the starting time and duration of the disturbance, alsoidentifying and analysis, LCD module displays transient parameters of the grid, Keyboard inputmodule performs parameter setting and display switching, SPI serial communication moduleextends the communication function with external system.The paper uses db4 wavelet transform to detect the transient power quality disturbances andthe obtained algorithm circuit can detect the voltage sags, swells, interruptions and oscillations.Verilog Hardware description language (Verilog) and FPGA are used to describe the circuit andrealize the above algorithm. The results show that the detecting algorithm circuit achievesexcellent detecting effect.Finally, this paper describes summarization and prospects of the research. What's more, theSOPC has been verified monitor systematic correctness by the series of testing experiment.