Innovative magnetic field calculation from multiple-circuit twisted three-phase lines

Multiple-circuit twisted three-phase cable lines are typically used for connecting renewable resources (e.g. photovoltaic and wind power) to the power grid. The magnetic field generated by such lines should be evaluated carefully whenever connecting such renewables to the network. This paper examines for the first time the calculation of the magnetic field generated by such lines. In the framework of a worst-case approach, the paper extends to multiple-circuit twisted three-phase cables both the exact treatment derived from the literature about singlecircuits and a simple innovative formula developed for single and double circuits by the authors, that resulted a good approximation of the rigorous analytical treatment and much more accurate than an approximated formula found in literature. The paper shows that the "worst case" approach yields an approximate yet conservative expression for the total magnetic field generated by multiple twisted three-phase power cables, whose effectiveness is further enhanced by the use of the simple innovative formula, as proved by case-studies examined here for triple-circuit twisted three-phase cables in various configurations. © 2013 Praise Worthy Prize S.r.l. - All rights reserved.