Research Of The Power Quality Monitor System Based On DSP And Parameters Design

Power is gradually important in modern society. In a sense, the using degree and range of electricity represents the strength of a country's economy and the overall development level. With the increase of power generation methods and expand of power stations scale, electricity has completely guarantee the industrial production needs and people's living power demand in numbers.The injection of large of nonlinear loads made grid structure complicated and cause power quality declining and serious influence production process and life quality. The purpose of power quality monitoring system is to ensure real-time monitoring for whole power system, automatic transmission for data and statistic analysis. It has important guiding significance for improvement and guarantee of power quality.After understood research meaning and purpose for the power quality and studied some related national standards, the system design a Power Quality Monitor System uses the double CPU mode which takes the DSP TMS320F28335 C8051F340 as the data processing core and the SCM C8051F340 as the operation control center to realize real-time monitoring and parameter calculation.The article firstly researched some important power quality parameters, then gave the corresponding measuring principle and calculation equation; The research is mainly about Fast Fourier Transform and Wavelet Transform that constantly used in harmonic analysis. The combination FFT aiming at real data about voltage and current is put forward and computations of different transformation are compared. This article then studied obtain decomposition layers of multi-resolution analysis and application of wavelet packets in signal decomposition. Then Fourier Transform and Wavelet Transform are compared; Hardware design of the power quality tester., and then gives the main module:switching power supply circuit, A/D sampling circuit, automatic range selection circuit and parts DSP digital signal system circuit; Get voltage and current data to be analyzed from power system, calculate parameters with the corresponding formulas and algorithm and verify experiment result use Matlab7.0 and wavelet analysis toolbox. Results show that this three-phase power quality detector completely meets the national standards and has high application value.