Electromagnetic Compatibility in Railways – Electromagnetic Field Measurement

A modern railway system may be a very complex system, with a large extension in space and a deep impact on the territory and existing installations. Many subsystems interact with more or less evident EMC interfaces spanning various coupling means and configurations for sources and victims. Although analysis and simulation are nowadays extensively used since system design, for several reasons experimental assessment and verification still play a major role: complexity of phenomena does not lend easily to modeling and simulation, provisions and countermeasures need to be verified and compared, or, as it is commonly the case, applicable standards and regulations require so. The aim of this book is the definition of the correct procedures for the preparation and execution of tests and measurements on-site for the assessment of EMC interfaces or phenomena in railway transportation systems, addressing problems of theoretical and practical nature. The attention is focused on methods of measurement and characterization of electromagnetic field emissions, that involve subsystems and third parties at various extent: emissions to outside world for railway system certification, disturbance to radio communication systems and sensitive scientific and medical equipment, human exposure. Many elements characterize a test or measurement: adequate instrumentation must be selected, not only for performance, but also for suitability to real conditions; the test setup must be clearly described and as simple as possible; operating conditions shall be defined from different viewpoints of driver, test operator and site manager; the test procedure must be unambiguous and detailed enough for the different purposes; the means of verification of operations and conditions need to be identified and understood, as well as methods for processing and evaluation of results. A correct, unambiguous, exhaustive and complete test procedure requires the knowledge of many elements, requisites and exigencies: materials and equipment, measurement theory and uncertainty, personnel, impact on circulation and safety. It will sound strange, but even mature standards focusing on a well defined EMC interface or phenomenon may fail to give a complete description and characterization of the problem, leaving out important details.