Study On High-Order Harmonic Resonance And Countermeasures Of Electrified Railway

In recent years, the number of high-speed EMU and AC-DC-AC electric locomotives that our country put into operation is increasing dramaticly.Compared to traditional AC-DC electric locomotives, AC-DC-AC electric locomotives have many technical superiorities, such as the bigger traction power, the smaller integrated harmonic current distortion and the higher power factor. But the harmonic spectrum they injecting to traction power supply system is widened and the harmonic content is increased. If the high frequency harmonic current frequency overlap with the natural frequency of the traction power supply system, then it is easy to cause harmonic resonance of the traction power supply system. Dueing to the harmonic resonance, many cases occurs, such as the damage of power supply equipments for electrified railway, even affecting the normal and safe operation.On the basis of in reference to related literatures, this paper summarizes the higher harmonic problems in traction power supply system and its harm, and the mechanism of higher harmonic resonance and harmonic current amplification are expounded. Combining with several existing high-pass filters, a new type filter— the fundamental wave preventing high-pass filter technology solutions is put forward. The characteristics of these filters are analyzed and compared through the establishment of simulation model of traction power supply system. Then combining with the measured data from field tests, the actual effects of the new technology solutions are evaluated.Combining with the actual situations of the current traction power supply system, the harmonic simulation model is set up through Matlab/Simulink platform. On the basis of the model, filtering characteristics and harmonic suppression characteristics of the proposed filter are studied, and a comparison between the fundamental wave preventing high-pass filter and existing high-pass filters has been carried on. Moreover, studies and analysis on the switching on-off transient characteristics of the proposed filter are maked. And the influence of the resistor values to filtering effects and transient characteristics of the fundamental wave preventing high-pass filter are studied mainly.Finally, the testing schemes based on the fundamental wave preventing high-pass filter are given in the article.The filter’s practical application in the traction power supply system and in three-phase power system were respectively studied. Combining with the Beijing-shanghai Harmonic Governance Project, the designing scheme and technical conditions for hang straight AT traction network based on the fundamental wave preventing high-pass filter are put forward. AT the same time, the development, installation and operation of the 380V fundamental wave preventing high-pass filter are completed. Then combining with the measured data from field tests, the actual operations of the fundamental wave preventing high-pass filter are analyzed and evaluated.