Author(s)

E. Cinieri, S. Cosmi, A. Fumi, V. Salvatori & W. Torto

Abstract

New prospectives for digital protections of the 3 kV DC electric traction lines E. Cinieri*, S. Cosmf, A. Fumi^, V. Salvatori* & W. Torto* ' University ofL' Aquila, Italy. ^Ferrovie dello Stato S.p.A., Divisione Infrastruttura, Italy. Abstract The increase of currents through lines in normal operation, due to the increase of train traffic and of the power absorption of the trains, especially the new High Speed trains, has led to a condition such that the intensity of the currents in normal operation is approaching the same order of magnitude of that for faults located in positions far from the ends stations. It is therefore a difficult task to discriminate between a faulty situation and that of a temporary high load condition. The addition to the maximum current protection relays of devices sensitive to the derivative of the current has not solved this problem in many practical cases. This paper present the results of a study performed by experimental tests and numerical si

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