Power System With Noise Harmonic Detection And Treatment Research

In modern society, electric energy has always been such an indispensable resource that plays an extraordinary role in human life. With constant development of industry and economy, quality requirements have become increasingly higher for electric energy. However, the electric energy quality has been greatly reduced owing to harmonic. To gain more ideal electric energy, it seems very urgent and has momentous significance to detect and govern the harmonic. As a result, one of the hot issues in the electricity field is how to detect the harmonic rapidly and accurately and how to manage it in real time.In the procedure of harmonic detecting and governing, the former is more important. At present, harmonic is detected generally by fast Fourier algorithm for harmonic detector in market. In general, non-stable signal limitation from Fourier analysis and noise existed in power system signal make it unpractical for harmonic detecting only by fast Fourier algorithm. For wavelet transform, signals of different bands can be decomposed into diverse scales due to the characteristics of multi-scale and multi-resolution ratio. So the signal characteristic point can be inspected exactly for non-stable power system signals.In the research, the de-noising problem for harmonic signals is first studied while traditional wavelet threshold de-noising is improved, with a new way proposed. It is greater than traditional wavelet threshold and Fourier transform de-noising. Then, aiming at characteristics of harmonic, Fourier transform and wavelet transform, a harmonic detecting method is put forward by combining fast Fourier transform with MALLAT algorithm. And specific advantage is also researched for algorithm, compared with harmonic catastrophe point detecting. At last, harmonic governing is studied, especially for AFP. The validity of harmonic governing is studied by constructing SIMULINK simulation model. Besides, data processing module of front-end harmonic and FPGA minimum system are also designed. In FPGA minimum system, the simulation is analyzed for FFT core, which verifies that FFT core may be well used for harmonic detecting algorithm.