Phototube sensor for monitoring the quality of current collection on overhead electrified railways

A new measurement system able to detect the occurrence of arcing between th e pantograph and the overhead contact line was studied and set up. The syst em uses photomultiplier tubes to measure the duration of the ultraviolet em ission due to electric arcing. The major advantages of the system proposed are its non-invasivity with respect to the pantograph equipment, its reliab ility and its low cost. Correlation with data acquired during high-speed te st runs from different sensors (e.g. currents measured in an equipotential wire between the front and the rear pantographs, images acquired from a TV camera), provided the opportunity to perform an efficient calibration and a n analysis of selectivity of the phototube sensor. Data from the phototabe sensor along with various other information lead to the definition of a reliable index for evaluating the quality of the curre nt collection. The determination of such an index has primary relevance for maintenance activities, for computing the minimal thrusts to be applied to the pantograph at different speeds and for testing new materials for overh ead contact wires and collector strips.