Power System Based On Detection And Analysis Of Power Quality

Power quality problems have become increasingly prominent for the rapid growth of non-linear load capacity of the transformer, rectifier and other devices; the other hand, with the development of modern science and technology, more and more sensitive load to power quality has a higher demand. Therefore, the power quality is increasingly attracted attention. To improve the power quality is important for the power grid, electrical equipment safety, economic operation, and to protect the normal production and people's lives. The monitoring indicators of power quality is the basis and premise to further improve the power quality.Paper first discussed the research background, and then the basic concepts of power quality and standard was introduced, the research status of the power quality measuring technology and development trend was analysed, and the research scope of this paper and the main work was introduced.In the second part of the paper, the detection of harmonics and flicker common approach was described for the power quality detection methods. The basic principles of wavelet and the instantaneous reactive power was highlight, based on their respectiveperformance characteristics, the application scope, the advantages and disadvantages of several power quality detection method was analyzed. The third part of the paper focused on steady-state harmonic detection methods. The instantaneous reactive power theory based on the improved algorithm of harmonics detection was studied, which took the the power system simulation platform of Harbin Engineering University Power Systems Laboratory as platform. According to the instantaneous reactive power theory, through the positive sequence component extraction, presented an improved detection method for power grid voltage is symmetrical but the aberration is asymmetric and distorted power grid voltage, grid current is symmetrical but the aberration, grid current does not symmetry and distortion, grid voltage and current any state such as five kinds of situations harmonic detection. Simulation results show that the harmonic detection method to improve the effectiveness.The fourth part focused on the transient voltage flicker and harmonic detection method. Because voltage flicker has a short-term characteristics, so a thesis based on the voltage flicker detection algorithm of continuous wavelet transform (CWT) was studied. In addition, for the transient harmonic problems, an improved detection algorithm - "db harmonic wavelet packet detection algorithm based on wavelet filter anti-aliasing" was proposed.Finally this paper gave the experimental and simulation results which proved the correctness and validity of the theoretical research, they also have a certain breakthrough and improvement with the comparison of some common algorithms. At the same time the hardware circuit was built to further verify the correctness of the algorithm.