Prediction of magnetic fields in multiconductor systems with significant harmonic currents

摘要

Electric and magnetic fields produced by transmission systems have received strong interest both for biological effects and for interference with electrical and electronic devices, measuring sets, computers, control systems, etc. A deeper attention has been more recently devoted to magnetic fields which are difficult to screen and which can be significant when produced by transmission, but also by distribution and utilization systems. This paper proposes a simplified approach which seems to be useful in the case of lines set up by cables and, in particular, when more cables are connected in parallel, considering currents affected by significant harmonics content. Complete simulation results for several selected cases to analyze the electromagnetic field under quasi-stationary conditions in a multiconductor system are reported and discussed in detail, and the main results are summarized. It was found that the parallel connection of conductors can amplify or reduce magnetic field amplitude with respect to the single conductor case and that this effect depends on the harmonics order.