Statistical Distribution of Energization Overvoltages of EHV Cables

Statistical distributions of switching overvoltages have been used for decades for the determination of insulation levels of extremely high voltage (EHV) systems. Existing statistical distributions obtained in the 1970s are for overhead lines, and statistical distributions of switching overvoltages of EHV cables are not available to date. This paper derives the statistical distribution of energization overvoltages of EHV cables. Through the comparison of the statistical distributions of EHV cables and overhead lines, it has been found that line energization overvoltages on the cables are lower than those on the overhead lines with respect to maximum, 2%, and mean values. As the minimum value is almost at the same level, standard deviations are smaller for the cables. The obtained statistical distributions in this paper are of a great importance in considering insulation levels of cable systems.