Methodology for the Accurate Measurement of the Power Dissipated by Braking Rheostats

Sensors

Martin Sira¹  Davide Signorino²  Domenico Giordano²  Daniele Gallo³  HelkoE. van den Brom⁴ 

[1] CMI, Okružní 31, 63800 Brno, Czech Republic;Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy;Università della Campania “Luigi Vanvitelli”, 81031 Aversa (CE), Italy;VSL B.V., Thijsseweg 11, 2629 JA Delft, The Netherlands;

关键词: power measurement;    braking rheostat;    regenerative braking;    current transducer;    frequency characterization;    chopped current;   

DOI  :  10.3390/s20236935

来源: DOAJ

【 摘 要 】

The energy efficiency of transportation is a crucial point for the rail and metro system today. The optimized recovery of the energy provided by the electrical braking can lead to savings of about 10% to 30%. Such figures can be reached by infrastructure measures which allow the recovery of the breaking energy that is not directly consumed by the rail system and dissipated in rheostat resistors. A methodology for the accurate estimate of such energy is valuable for a reliable evaluation of the cost–benefit ratio associated with the infrastructural investment. The energy can be estimated by measuring a braking current flowing in the rheostats. The varying duty-cycle associated with the high dynamic variation, from zero to thousands of amperes, makes the current measurement very challenging. Moreover, the digitization of such waveforms introduces systematic errors that affect the energy estimation. To overcome these issues, this paper proposes a technique to measure the power and energy dissipated by the rheostat of a DC operated train with high accuracy. By means of an accurate model of the electrical braking circuit (chopper and rheostat) and the frequency characterization of the current transducer, a correction coefficient as a function of the duty-cycle is estimated. The method is then applied to data recorded during a measurement campaign performed on-board a 1.5 kV train of Metro de Madrid during normal operation. Using the proposed technique, the estimation of the dissipated braking energy is improved by 20%.

【 授权许可】

Unknown