Electric Power Derivation From 25 kV AC Overhead Line Systems: A Solution for Electrified Railway Networks

Abstract

Decarbonizing rail transport in response to global warming is fundamental to achieving a net zero transportation system. Along with increased passenger mobility and network electrification initiatives, significant connectivity between the train and infrastructure is needed to underpin operational communications and safety, information exchange, and customer comfort. Track-to-train data connectivity solutions that are being proposed require a source of electrical power available at regular locations. This source of electricity is not always readily accessible along the railway track, even when the traction systems are powered by electricity. For low-power and low-voltage (LV) applications, deriving electric power from the overhead catenary system is costly, potentially bulky, complicated, or not even technically feasible with present conventional or innovative power derivation methods. This paper investigates the technical feasibility and applicability of the capacitive divider technology in electrified AC traction systems and proposes a power supply solution that could utilize the in situ 25 kV AC overhead line to supply low-power LV applications. A prototype has been developed, and the principles of deriving active power up to 47 W at 108 V have been demonstrated through laboratory experiments and simulations. The prototype has a relatively low complexity, does not require any auxiliary power supply circuitry, has relatively a lower cost compared to other solutions, and can be constructed rapidly due to the availability of off-the-shelf components. The proposed power supply solution has the potential to support data connectivity applications thus becoming an enabler of the information exchanged between train and infrastructure.