DocumentCode :
1428871
Title :
Thyristor chopper control and the introduction of harmonic current into track circuits
Author :
Lowe, T.J. ; Mellitt, B.
Author_Institution :
London Transport, Acton Works, London, UK
Volume :
121
Issue :
4
fYear :
1974
fDate :
4/1/1974 12:00:00 AM
Firstpage :
269
Lastpage :
275
Abstract :
Alternating currents will generally be present in a d.c. traction supply owing to the action of synchronously switched power-control equipment and also to the presence of mains-frequency-harmonic voltage ripple. This paper describes the factors that determine the magnitude and frequency of such current in the power rails, for various conditions of d.c.-chopper operation. Models that describe the introduction of harmonic current into track circuits are developed from power-circuit considerations, and theoretical predictions are compared with practical results obtained from measurements undertaken by London Transport. The use of multiphase chopper equipments to reduce the size of the input filter is considered, and it is shown that, when normal-load unbalance conditions are considered, no advantage is gained by using more than two phases.
Keywords :
harmonics; railways; thyristor applications; traction; DC power railway; DC traction; harmonic current; railways; signalling; thyristor applications; thyristor chopper control; track circuits;
fLanguage :
English
Journal_Title :
Electrical Engineers, Proceedings of the Institution of
Publisher :
iet
ISSN :
0020-3270
Type :
jour
DOI :
10.1049/piee.1974.0052
Filename :
5250839
Link To Document :
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