The Research Of Power Information Collection Terminal Based On DSP

With extensive input from non-linear load and a variety of fluctuating and impactive device,power grid appears a lot of harmonics and seriously affect the normal electrical power quality and power users.Therefore,it is important to achieve the power information collection terminal with high precision harmonic detection.In this paper,the improved algorithm is applied to calculate the harmonic parameters in the power information collection terminal,improving the accuracy of harmonic detection.The parameters of detected harmonic and the rest of power quality need to be transmitted to the host computer interface displayed through communication methods.The monitored information data will be preserved and analyzed.It can also provide the basis for further improvement of power quality.First,in view of the steady-state harmonic under the non synchronous sampling,there will be a spectrum leakage and fence effect phenomenon which affects the accuracy of harmonic detection by the Fourier transform method.The traditional windows and interpolated FFT algorithm uses window function and interpolation operation to improve the accuracy of detection,but there are still the larger errors.This paper proposes the improved DFT algorithm based on frequency domain expansion in connection with fence effect.It needs appropriate scale in frequency spectrum to observe in right down line,reducing the fence effect and improving the detection accuracy.At the same time,it avoids the interpolation arithmetic computation.The improved DFT algorithm and traditional windows and interpolated FFT algorithm are analyzed in depth,and the calculation process of algorithm is derived in detail.Secondly,TMS320F2812 is selected as the core processor,completing the hardware and software design of collection terminal.The test is based on frequency domain simulation telescopic improved DFT algorithm and windows and interpolated FFT algorithm,analyzing on the calculative result error and comparing the merits and demerits of the two algorithms.The results confirm that the improved DFT algorithm is slightly better than windows and interpolated FFT algorithm.So the improved DFT algorithm is selected as the algorithm of harmonic detection on DSP.At the same time,the rest of power quality parameters are calculated,including the RMS,active power,reactive power,apparent power,power factor,and the content of harmonic,harmonic distortion rate,the three-phase imbalance degree,and the power information collection terminal based on DSP is completed.Finally,the user-side power information management platform is completed based on LabVIEW software.The harmonic parameters and the rest of power quality were calculated by the power information collection terminal,transmitted to the host computer through appropriate data communication methods based on LabVIEW.It need to design multiple interface on the PC interface that show all parameters of the power quality respectively,so as to realize the scientific management of the power quality parameters.It provided a good start to follow-up study in depth how to implement energy saving DSM platform.