live-line working in electrical engineering, also known as hotline maintenance, is the maintenance of electrical equipment, often operating at high voltage, while the equipment is energized.
The first techniques for live-line working were developed in the early years of the 20th century, and both equipment and work methods were later refined to deal with increasingly higher voltages. In the 1960s, methods were developed in the laboratory to enable field workers to come into direct contact with high voltage lines. In this report, we will introduce such methods of working which will include bare hand, hot stick and rubber gloves methods. However, to have an efficient insulating equipment that lets the workers work on live lines, we need to illustrate the electric arc model and the protection thermal from it.
Usually when having a fault in the electric power system, a high current fault arc occurs at the faulted point. Since the temperature of the high current fault arc is very high, it sometimes causes damages not only at the fault point, but also in the surrounding apparatus. Therefore, it is very important to investigate the fault arc phenomena to be able to recover quickly from the fault, define its causes and act to prevent faults in the apparatus.
Electric arcs can simply be modeled by a circuit that have mainly two parameters, voltage of the arc and resistance. Both voltage and resistance of the arc are function of distance as they vary with varying it. In this report I will introduce the electric arc circuit model and its parameters alongside with live line maintenance working techniques in electric power systems. Later, we will introduce different common live-line jobs, assess the risks of arcing in case of selected live-line activities.