Conducted and radiated interference on the interconnections of renewable energy farms

Abstract

Electromagnetic disturbances are usually classified into conducted and radiated disturbances, which are rather loosely defined. That causes confusion among the people that work in the area, in different time scales. In this paper we put forward a formulation of the electromagnetic coupling, based on the potentials, that, when the matter is described by constitutive laws, is valid in any time scale, thus providing a common framework to study conducted and radiated interferences. We show that, for a transmission line, the electromagnetic field can be separated in two independent modes: a longitudinal TM mode and a transversal TE mode. We also show that the scattered field is a longitudinal TM mode and that, for usual transmission lines, the longitudinal mode can be described by Kirchhoffs laws. We show that the conducted disturbances are just a common longitudinal mode; while the radiated disturbances can conveniently be divided into a longitudinal mode and a transversal mode. For the longitudinal mode, its effect can be represented as a voltage or current source, and, the effect of the transversal mode is just to produce an induced voltage between the conductors. Finally, we present some application examples to illustrate the usefulness of this interpretation.