An improvement for the selection of surge arresters based on the evaluation of the failure probability

An improvement on the typical selection procedure of arresters is presented. The analysis shows that the risk of failure of an arrester depends on several parameters (the striking point, the lightning current waveform, the arrester itself and the system configuration). Therefore, the selection of the optimal arrester depends on how well its stresses can be estimated. After the application of the typical selection procedure, the power system simulations are carried out using the Electromagnetic Transients Program (EMTP) for each suitable arrester. From these results the failure probability of each arrester is calculated, which permits the optimal selection from several valid arresters by the comparison of their risk of failure.