Long arc in free air: laboratory testing, modelling, simulation and model-parameters estimation

The results of an investigation into the long arc in free air is presented. The long arc in free air is initiated under laboratory conditions in the FGH-Mannheim high-power test laboratory (Germany). Based on the arc voltage and the arc current data records obtained in the laboratory, the main features of the arc are derived. In the second stage of the research, a new arc model is developed. The arc is modelled as a current dependent voltage source with the characteristic distorted rectangular waveform. Examples of computer simulations of the arc using new models are given. The main features of the simulated arc are also described. Features of the real and modelled arc are given in the time and the spectral domains. The interaction between the arc and the network is analysed. Through computer simulation, a typical example of an arcing fault on an overhead transmission line is given. Finally, the least squares error estimation method for arc model parameter estimation is presented. The unknown model parameters are successfully estimated from the computer-simulated and laboratory-obtained data