Overvoltage protection of the new 100-kV cables in HPP Senj
Abstract
The paper deals in detail with the issue of optimal overvoltage protection of new 110 kV cables in the Senj HPP, which connect the block transformer to the external switchgear. The expected: (a) temporary overvoltages (due to the occurrence of ground faults and their elimination, due to sudden generator load shedding and sudden load shedding in the plant) were analyzed: (b) switching overvoltages and (c) atmospheric overvoltages. The selection procedure for metal-oxide surge arresters was carried out, as well as numerical simulation of their operation due to the occurrence of expected unfavorable overvoltage situations. All numerical simulations were carried out in the EMTP-ATP software package with detailed models of all components of the observed system. Insulation coordination with the selected surge arresters was also carried out. Finally, a recommendation was given for the optimal treatment of the screen of the new 110 kV cable line, especially considering that it is a cable located in the tunnel through which the block transformer is connected to the external switchgear.
