Arc protection during live-line maintenance on high voltage systems

Live-line maintenance (LLM) has special requirements for the equipment, which protects the LLM personnel from different kinds of hazards - especially in high voltage transmission systems. Conductive clothing provide protection for the primary effects of the high electric field acting as a Faraday cage. However, this kind of protection cannot guarantee the proper safety against all other possible threats. One of the potential hazards is the emitted energy of the power electric arc. Basically the extent of the emitted incident energy shall be calculated to estimate the risks related to the electric arc affecting the worker. The calculation needs a special method, which takes the consequences of the dimensional characteristic and other properties of the high-voltage network beside the characteristics of the high-current arc into account. This paper explains a method for the estimation of the emitted energy of an electric arc and a calculation method in the high-voltage system in the case of LLM in order to find out whether the existing protective materials are capable of providing proper protection for LLM personnel against the incident energy.