This thesis deals with the issue of electromagnetic fields generated around the conductors of the overhead power lines. The aim of the dissertation thesis is to provide a deep insight into the electromagnetic field calculations and their properties and to analyze their technical potential. Electromagnetic fields have significant impacts in the power line design and surrounding objects and infrastructure. The work presents a model with software implementation, which has been expanded with the possibility of calculating in real conditions. All calculations are verified using analytical solutions, finite element methods, laboratory measurements, and real measurements. Borderline work deals with public debate on the harmfulness of electromagnetic fields on human health. A very detailed legislative framework is being analyzed in the thesis. This legislative framework is compared within the whole of the European union. The work analyzes selected factors like meteorological factors, environmental influences, design factors and influence of power system operation, affecting electromagnetic fields. The thesis analyzes the technical possibilities of the electromagnetic fields. Several options are analyzed in the work including the use for localization of faults or measurement of current asymmetry. A prototype of a magnetic flux density measuring device was constructed as a tool for the research of this technical potential. Furthermore, the values of electromagnetic fields of power equipment, transformer stations, trains, household appliances, were obtained from real measurements and compared.