Physical modeling of arcing ground fault in cable insulation and statistical analysis of experimental results

Existing models on arcing ground faults do not represent exactly parameters of transient processes at single-phase faults in power cables. This paper presents the results of analysis of amplitude, velocity and time parameters for currents and voltages at arcing ground fault in power cable. The analysis is based on random samples obtained from real oscillograms. These oscillograms are recorded during experimental investigations in the 6 kV network. Hypotheses of distribution laws, outliers detection and correlational relationship are tested. Regression statistics is obtained for main parameters of arcing ground fault in impregnated cable insulation. Obtained statistical characteristics for arcing breakdown parameters can be used for further development of mathematical models of arcing ground faults in power cable insulation and for checking of relay protection efficiency using physical models. Statistical characteristics of arc power and arc resistance obtained at intermittent ground faults are considered as integral arc parameters.