A Distributed Measurement System for Synchronized Energy Analysis in Railway Applications

Reducing transport emissions through electrification and improving energy efficiency is a widely studied and crucial topic. Although electric railways are inherently efficient, traditional DC systems often waste significant regenerated braking energy due to unidirectional power flow of supply substations. Solutions like reversible substations (RSS) offer a remedy by re-injecting this energy into the main AC grid. However, there is a lack of standard methodologies to evaluate their efficiency and experimental procedures to accurately quantify the energy savings associated with their use, for example by measuring improvements in 'line receptivity', in real systems. This paper presents the first-ever synchronized, distributed measurement campaign conducted underground across an entire Madrid metro line, which operates with a RSS. The paper provides some preliminary data on real-world energy flows, highlighting the importance of accurate and synchronized measurements to understand the role of energy-saving technologies such as RSS in the operation of real metropolitan systems.