Handling of magnetic field-related risks during live-line maintenance

Protection of live-line personnel against the possibly harmful effects of non-ionizing radiation - such as extra-low frequency electric and magnetic fields - is one of the keys of safe working. Limits of these fields are defined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Exposures above limits may endanger the safety of the workers, so are not acceptable during any kind of live-line activity. Although magnetic fields have similar - even more dangerous - health-related risks than electric fields, these are usually not taken into account at all during the preparation and the execution of any live-line work. In the High Voltage Laboratory of Budapest University of Technology and Economics calculations, simulations and measurements were executed to inspect the critical exposures. Results have shown that in some cases induced current density in the human body may reach the limits, so protective actions are required to increase the safety of this method. Based on the results, an expert system can be developed to handle magnetic field-related risks before - even continuously during - any live-line activity. By the application of these improvements, exposures can always be kept under the limits during any kind of work. This paper not only focuses on the theoretical background of the analysis - the possible practical implementation is also introduced.