Research Of The Electric Power Harmonic Detection System Based On FPGA

Electric power harmonics influence the power quality, increase the loss of the power grid, and reduce the operation efficiency and reliability of power system because of its inherent characteristics. They seriously threaten the safe and stable operation of power system, and have become a great public hazard of power system. Now the harmonic treatment has been imperative.Accurate and rapid detection of harmonics is the basis of dealing with all the problems about harmonics. Up to now, the extensive research on electric power harmonic detection methods have been conducted, but on the whole, the effect is not ideal. Therefore, it is of very important practical significance to explore an effective method of harmonic and develop power harmonic detection system with real-time measurement and high precision.This thesis proposes a method for electric power harmonic detection, which breakthroughs the restrictions from the two aspects of the hardware architecture and software algorithm. A thorough research of it has been made. The main research work includes:1. A new thinking and method of harmonic detection is made from the two aspects of the hardware architecture for solving the problem of "the real-time harmonic detection" and the software algorithm for solving the problem of "harmonic detection accuracy" by deeply analyzing the principle and limitations of existing harmonic detection method. The basic idea is to complete a large number of FFT algorithm to raise the speed of operation by choosing high-performance FPGA, and to raise the accuracy of operation by means of improving FFT algorithm, namely, a FFT algorithm of triple-spectral-line interpolation with Rife-Vincent window.2. The system hardware design has been completed. The system hardware design mainly includes that of harmonic signal acquisition and preprocessing circuit and that of FPGA master control circuit and the corresponding configuration, etc. Among them, the signal acquisition and preprocessing circuit is mainly composed of voltage acquisition circuit, current sampling circuit, signal pretreatment circuit and AD sampling circuit, etc; The FPGA control and the corresponding configuration circuit includes master control chip of FPGA, storage circuit, configuration and display circuit, etc.3. The system software design and programming algorithm have been completed. Of which the AD sampling control, windowing, FFT algorithm and the interpolation arithmetic algorithm are included. In the Quartus II environment, the configuration of the parameters has been implemented by VHDL programming or by calling the built-in module in the platform, and on the basis of it, the correctness of the software modules has been verified by simulation.4. The harmonic detection experimental system based on this method and the architecture has been constructed, and the actual test has been made. Finally, a comparison and analysis of the experiment results and simulation results have performed performed. The results show that the developed electric power harmonic detection system can effectively detect the harmonic parameters in power grid, and it is characterized by high precision, good real-time performance and the strong anti-interference ability.