Electromagnetic fields characteristics from overhead lines, underground cables and transformers determined using finite element method

Abstract

Electromagnetic fields (EMF) are combinations of invisible electric and magnetic fields of force collectively where electric fields are proportional to electric charges, and magnetic fields are proportional to electric currents. Those fields may have detrimental potential health effects and can be in our homes or workplaces. There are many uncertainties about those emissions. This research is to clarify and answer those questions. This study focuses on magnetics fields only as it can vary. therefore, this project is to simulate and analyse magnetic fields radiations in the vicinity of 132 kV overhead power lines for two cases; with straight conductors and with conductors sags, 11 kV triangular straight underground cable for two cases; as 185 mm2, and 120 mm2 cross sectional area at 0.9 m in depth, and for 1000, 1600, and 2000 kVA transformers determined using finite element method via ANSYS Maxwell. Also, to compare the results with the safety limits as defined in recent international standards. The results for 132 kV double circuit overhead power transmission straight lines show a highest magnetic field magnitude of 38 µT while with conductors sags a highest magnetic field of 51.2738 µT. For underground cables, the results show 185 mm2 bigger cross-section area cable has higher magnetic fields compared to the smaller cross section cable with the highest magnetic fields of 97.6598 µT and 44.89 µT respectively. For transformers, the highest magnetic field was obtained by applying peak load current to the upper and lower windings in each phase for each geometry models and examined both far and near fields in two directions. The highest magnetic field obtained for far fields of 2000 kVA transformer is 110.50 µT. Those fields data are collected at one meter high. The allowable limits are set in ranges (200-1000 µT) and (0.9-3mT) for ICNIRP 2010 and IEEE 2019 respectively based on 50 Hz. The results are showing safe exposure level of magnetic fields as long as the distance is respected. It is advisable that safety precautions should be taken to prevent prolong exposure of EMF radiation to human body.