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.