During live-line maintenance in case of high voltage transmission networks, the length of an occurring electric arc can reach several meters because of the high clearance between the electrodes and the hundreds of kilovolts, in addition due to the high performance of the power supply the current of the fault arc can be several kiloamperes. For this reason, the professionals in the vicinity of the arc may suffer extremely high levels of various harmful effects. When establishing arc protection, the first purpose is to prevent the initiation of arc and to decrease the emitted energy of the arc to the lowest possible level. In addition, assuming that arc initiation is still possible, the worker has to be protected against the harmful effects of the electric arc by the use of adequate personal protective equipment (PPE).
The main aim of this paper is to investigate the theoretical background of some methods – personal protective equipment and portable preventive air gap - of arc protection and present their application in case of high voltage live-line maintenance. The calculation model to determine the properties of PPE as well as the theoretical method and laboratory measurement and their evaluation are shown in this work.