A Novel Arc Detection Method for DC Railway Systems

Abstract

Electric arcing due to contact interruption between the pantograph and the overhead contact line in electrified railway networks is an important and unwanted phenomenon. Arcing events are short-term power quality disturbances that produce significant electromagnetic disturbances both conducted and radiated as well as increased degradation on contact wire and contact strip of the pantograph. Early-stage detection can prevent further deterioration of the current collection quality, reduce excessive wear in the pantograph-catenary system, and mitigate failure of the pantograph contact strip. This paper presents a novel arc detection method for DC railway networks. The method quantifies the rate-of-change of the instantaneous phase of the oscillating pantograph current signal during an arc occurrence through the Hilbert transform. Application of the method to practical pantograph current data measurements, demonstrates that phase derivative is a useful parameter for detecting and localizing significant power quality disturbances due to electric arcs during both coasting and regenerative braking phases of a running locomotive. The detected number of arcs may be used to calculate the distribution of the arcs per kilometre as an alternative estimation of the current collection quality index and consequently used to assess the pantograph-catenary system performance. The detected arc number may also contribute to lowering predictive maintenance costs of pantograph-catenary inspections works as these can be performed only at determined sections of the line extracted by using arcing time locations and speed profiles of the locomotive.

Modelling on the synergy of mechanical and electrical wear in a current line/catenary-pantograph system

“…Regarding the distillation of the wear parameter 𝑘 3 , usually image detection [12] or signal analysis from the measured current [13,14] is required to find the time fraction u of electrical arcing. Under all the parameters fixed experiment, the control of arcing fraction is difficult to perform.…”

“…The early detection of the emerging defect can prevent the catastrophic failure of the system [12]. From the measured current signal [13] or voltage signal [14] of the rolling stock in service, the identified arcing along the track can be employed to check the quality of the conducted current and the locations of abnormal wear. Moreover, the position deviation of the current line installation [2], installation quality of the wire junction of current line [15], environmental temperature [16] and moisture [1] are all factors needed to be monitored to ensure the reliability of the system.…”

Review of MVDC Applications, Technologies, and Future Prospects

“…Arcing in DC rail systems is intense, as the voltage is often lower compared to that of the equivalent AC systems, resulting in the current being higher [59]. Interruption between the pantographs and the overhead line can cause arcing and results in power quality issues, electromagnetic emissions, increased temperature at the contact point, and wear on the contact wire and strip on the pantograph [60]. Fast detection methods might be required to prevent the spread of negative electromagnetic phenomena throughout the rail network [61].…”

Modification of the Railway Traction Elements

“…The section insulator guides and the wires of the railway traction are made of copper (CW004A) Cu-ETP [2,3]. During operation, they are exposed to several tribological mechanisms, including corrosion (oxidation of copper), friction, abrasive wear, and arc erosion [4], the most destructive of which is an electric arc [5]. The generation of an electric arc causes disturbances in current flow, a rapid increase in temperature at the contact points [6], which leads to increased wear of the guides and the phenomenon of micro-welding [7].…”