Power Quality Analysis Of Traction Power Supply System Based On Mathematical Morphology

With the continuous development of world economy and technology, in China the demand of various related industries for commodities transportation speed and traffic volume are also growing. Because of its high speed, large load and low energy consumption, the position of electrified railway in the transportation industry in our country is more and more high, and the electrified railway has been an important infrastructure in transportation system. The electric traction engine made voltage and current distortion in the public grid, when it’s in the process of operation. This reduced the power quality of public power and traction power supply system, brought security hidden trouble to traction power supply system. A more efficient power quality analysis method is supposed to improve the power quality of traction power supply system in our country, so it has very important significance.Around the theme of power quality in traction power supply system, power quality analysis of research significance and status in traction power supply system were described in detail. Since there’re still some disadvantages in harmonic analysis methods, the mathematical morphology analysis tool is imported in this paper. Basic principles of mathematical morphology and law of morphological structure elements selection were introduced and the effect comparison of several common morphological filter had been done. As a result, the low pass filter of instantaneous reactive power algorithm may negatively affect the precision of harmonic detection. To solve the problem, mathematical morphology filter was proposed to replace the low pass filter to analyze the harmonic of current waveform in traction power supply system. And the concept of mathematical morphology harmonic content is defined to describe the harmonic content of a cycle for the first time. Experiments show that the combination of instantaneous reactive power algorithm and mathematical morphology filter can accurately detect the harmonic content in the traction power supply system. When the current amplitude fluctuation happened, the result of this scheme still can be real-time and precise.Secondly, different kinds of structure elements were used to eliminate the noise in traction power supply system. And the ability of noise removing was brought forward to evaluate morphological filter denoising effect. Then detected the disturbance signal in traction power supply system by morphological filter. Mathematical morphology filter can filter out the noise of the traction power supply system signals, and complete the disturbance signal detection and classification in the simulation. The result shows that mathematical morphology filter can well realize noise elimination and disturbance localization and classification in traction power supply system.Researches proves that the above methods are correct and effective. Experiments show that correct selection of structural elements of the length and shape and mathematical morphology filter may improve the analysis precision of local characteristics. Mathematical morphology theory can be used in harmonic analysis and disturbance detection in electrified railway traction power supply system with less amount of calculation and high speed of program running, etc.