Research And Implementation On Grid Harmonic Detection Method

Currently, the problem of power grid harmonic has attracted much attention, due to theexistence of a large number of harmonic, which affects the power quality seriously. Therefore, inorder to reduce and eliminate the hazards caused by harmonic, the research and real-time detectionof the power grid harmonic has very important significance.Firstly, this paper introduces the relevant knowledge of harmonic and the national researchstatus of harmonic detection, and studies several common harmonic detection methods. On thisbasis, this paper studies the applications of the Discrete Fourier transform and Fast Fouriertransform in the harmonic detection, and analyzes the basic principles of Fast Fourier transform forharmonic detection.When used in a non-synchronized sample sequence, applying the Fast Fourier transform in theharmonic detection can cause spectrum leakage and fence effect easily, in order to solve theabove-mentioned problems, this paper studied an algorithm based on Blackman-Harris’s windowinterpolation, and the simulation was carried out through the MATLAB, the simulation resultsshowed that window interpolation algorithm could effectively solve the problems of the spectrumleakage and fence effect.Due to the complexity of the grid environment, in order to understand the power grid ofreal-time harmonic components, this paper designed a harmonic detection system which regards theTMS320F2812as the main controller, the voltage current conditional circuit, the zero detectioncircuit and the DSP peripheral circuits were designed and implemented. And the circuit board forthe designed circuit was manufactured and debugged. The results showed the mentioned circuitsatisfied the requirements of the harmonic detection.On the basis of the hardware design, this paper designed the software modules of the system,writed the programs including the data collection, the data processing and the data transmission.And the corresponding experiments were verified. The experimental results demonstrated that thedesigned circuit can realize the function of harmonic detection.