Currents and potentials in earth-return circuits exposed to alternating current electric railways

Abstract

This paper presents a method of calculation of currents and potentials, excited by the electromagnetic effects of an AC-electrified railway system, along two infinitely long earth-return circuits buried in parallel in the vicinity of the tracks. Inductive and conductive coupling, exists within the railway system, and the earth-return circuit is taken into account, as well as interaction between currents flowing in both underground conductors, whereas the reaction of the conductors' currents on the track current is disregarded. The analysis given is applicable to any railway system in which the tracks may be represented by a single conductor with earth return. The technical applications of the method are illustrated by examples.