EPE Association: EPE 1997 â€“ 61: Dialogue Session DS5b-2: TRACTION

EPE 1997 â€“ 61: Dialogue Session DS5b-2: TRACTION - INTERFERENCE
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   Interference Currents at 3 kV DC Traction Application
By U. Ehrler; K.-H. Ketteler [View]
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Abstract: The electromagnetic compatibility to signalling systems was investigated for inverters directly connected to the 3 kV catenary. Following extensive measurements, the important sources of harmonics were identified and eliminated by appropriate control strategies.

   ANALYSIS METHODS OF LINE INTERFERENCES ON THE EXAMPLE OF A DC-LINE TRACTION DRIVE
By J.-T. Maass; R. Redmann; F. Unger-Weber; P. Terwiesch [View]
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Abstract: Frequency content of line currents due to electrical traction must meet predefmed limits. Generic criterias are signal frequency bands, amplitude and time limits. The most common analysis methods for demonstration of compliance are the Fast Fourier Transform (FFT) and bandpass filtering. While achieving good analysis results at steady. state conditions, both methods fail in the case of transient phenomena. Particularly on DC-lines, load or line voltage jumps that occur frequently require analysis methods v.hlch are better adapted to transients. Using synthetic data and real measurement data of a DC-line vehicle, the Berlin 8-Bahn, three different analysis approaches for line interference currents, FOURIER, BANDPASS and the new WAVELET analysis are compared. Gaining at least three different analysis results for the same measurement data a comparison and evaluation of the methods is performed. It is obvious that FFT is not suited for investigation of transients due to averaging and poor time or vice versa frequency information. Bandpass filtering shows better time and selective frequency information but reacts on every big transient with oscillations which could be misinterpreted as a disturbing current Wavelet analysis combines time and frequency information, but frequency resolution of the Morlet Wavelets used here is found to be poor. The comparison shows that further investigations in the field of combined methods and more advanced Wavelet methods is necessary.

   INTERACTION BETWEEN THE DRIVE AND THE LEVITATION SYSTEM OF THE SUPERCONDUCTING MAGNETICALLY LEVITATED SYSTEM
By Shunsuke Ohashi; N. Tanahashi; H. Ohsaki; E. Masada [View]
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Abstract: A superconducting (Se) magnetically levitated (Maglev) transportation system has been developed in Japan and a new test line has been constructed at Yamanashi prefecture. Although the superconducting electrodynamic suspension (EDS) system has the advantage of stable levitation without active control, various electromagnetic or mechanical disturbances can cause the change of gap length and the displacement or oscillation of the bogie. And the change of gap length causes the change of the thrust force of the drive system (LSM). Therefore in this system, interaction between the drive and the levitation system is very large. We developed three dimensional numerical simulation program for the Maglev train. This program includes the drive, the levitation and the secondary suspension system. Using this program, running simulation of the train for Yamanashi new test track was undertaken. To show the interaction between the drive and the levitation system, running characteristics of the train passing a curved section and in the case of the se coil quenching, were calculated.

   CONTROL OF LINE HARMONICS DUE TO FOUR-QUADRANT-CONVERTER IN AC TRACTIVE STOCK BY MEANS OF FILTER AND TRANSFORMER
By Wolfgang Runge [View]
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Abstract: To reduce the line current harmonics of traction vehicles fed from AC lines via Four-Quadrant-Converters (4QC), a filter connected to a special filter winding of the transformer is used. Structure and data of an equivalent circuit describing the transformer up to the kHz range are established by measurements. The filter layout of the loco series 10 l delivered by Adtranz to the Deutsche Bahn is treated. The calculated and measured results fully confirm the approach. Even in reduced operation mode with only two of four 4QC working, the psophometric current is kept at 1 A. For a precise calculation of harmonics the eddy current behaviour of the transformer needs to be considered.

EPE 1997 â€“ 61: Dialogue Session DS5b-2: TRACTION - INTERFERENCE
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 â€“ 61: Dialogue Session DS5b-2: TRACTION - INTERFERENCE
	[return to parent folder]

	Interference Currents at 3 kV DC Traction Application By U. Ehrler; K.-H. Ketteler	[View] [Download]
Abstract: The electromagnetic compatibility to signalling systems was investigated for inverters directly connected to the 3 kV catenary. Following extensive measurements, the important sources of harmonics were identified and eliminated by appropriate control strategies.

	ANALYSIS METHODS OF LINE INTERFERENCES ON THE EXAMPLE OF A DC-LINE TRACTION DRIVE By J.-T. Maass; R. Redmann; F. Unger-Weber; P. Terwiesch	[View] [Download]
Abstract: Frequency content of line currents due to electrical traction must meet predefmed limits. Generic criterias are signal frequency bands, amplitude and time limits. The most common analysis methods for demonstration of compliance are the Fast Fourier Transform (FFT) and bandpass filtering. While achieving good analysis results at steady. state conditions, both methods fail in the case of transient phenomena. Particularly on DC-lines, load or line voltage jumps that occur frequently require analysis methods v.hlch are better adapted to transients. Using synthetic data and real measurement data of a DC-line vehicle, the Berlin 8-Bahn, three different analysis approaches for line interference currents, FOURIER, BANDPASS and the new WAVELET analysis are compared. Gaining at least three different analysis results for the same measurement data a comparison and evaluation of the methods is performed. It is obvious that FFT is not suited for investigation of transients due to averaging and poor time or vice versa frequency information. Bandpass filtering shows better time and selective frequency information but reacts on every big transient with oscillations which could be misinterpreted as a disturbing current Wavelet analysis combines time and frequency information, but frequency resolution of the Morlet Wavelets used here is found to be poor. The comparison shows that further investigations in the field of combined methods and more advanced Wavelet methods is necessary.

	INTERACTION BETWEEN THE DRIVE AND THE LEVITATION SYSTEM OF THE SUPERCONDUCTING MAGNETICALLY LEVITATED SYSTEM By Shunsuke Ohashi; N. Tanahashi; H. Ohsaki; E. Masada	[View] [Download]
Abstract: A superconducting (Se) magnetically levitated (Maglev) transportation system has been developed in Japan and a new test line has been constructed at Yamanashi prefecture. Although the superconducting electrodynamic suspension (EDS) system has the advantage of stable levitation without active control, various electromagnetic or mechanical disturbances can cause the change of gap length and the displacement or oscillation of the bogie. And the change of gap length causes the change of the thrust force of the drive system (LSM). Therefore in this system, interaction between the drive and the levitation system is very large. We developed three dimensional numerical simulation program for the Maglev train. This program includes the drive, the levitation and the secondary suspension system. Using this program, running simulation of the train for Yamanashi new test track was undertaken. To show the interaction between the drive and the levitation system, running characteristics of the train passing a curved section and in the case of the se coil quenching, were calculated.

	CONTROL OF LINE HARMONICS DUE TO FOUR-QUADRANT-CONVERTER IN AC TRACTIVE STOCK BY MEANS OF FILTER AND TRANSFORMER By Wolfgang Runge	[View] [Download]
Abstract: To reduce the line current harmonics of traction vehicles fed from AC lines via Four-Quadrant-Converters (4QC), a filter connected to a special filter winding of the transformer is used. Structure and data of an equivalent circuit describing the transformer up to the kHz range are established by measurements. The filter layout of the loco series 10 l delivered by Adtranz to the Deutsche Bahn is treated. The calculated and measured results fully confirm the approach. Even in reduced operation mode with only two of four 4QC working, the psophometric current is kept at 1 A. For a precise calculation of harmonics the eddy current behaviour of the transformer needs to be considered.