A Method for Estimating the Magnetic Fields Generated by the Overhead Power Lines

In this paper we propose a new measurement method to estimate the spatial and temporal variability, namely to realize maps with magnetic induction B anywhere and anytime around overhead power line, using only two measurement instruments and a minimum number of measurements. Based on the obtained results of spot measurements and the results of an automatic survey of magnetic induction B, we estimate the profiles and the maps of magnetic fields anywhere near the line, i.e. spatial variability and anytime, i.e. temporal variability. These two sets of synchronous measurements where made with two independent instruments each of them having a measurement uncertainty below 5%. Firstly, the field profiles were determined by means of on spot measurement made at different time moments using a simple commercial instrument. Then, we adjusted these profiles, based on simultaneous and continuous determination of the time variability of B, obtained with our measurement system for automatic survey of the magnetic field. In order to make a complete characterization of the generated magnetic field, we also present, the time and frequency representations of B, a statistical processing of the results, and the profiles and maps of field when B is maximum/minimum. This is made in accordance to the field time variability (of about 8%), obtained during an hour of automatic survey of magnetic field in a single point.