accuracy. All the models presented low accuracy for the configuration with insulators considered (V-type string without shielding electrodes) thus underlining the necessity of further studies. However larger accuracy of the evaluation methods is expected for actual configurations, also in presence of insulators, in all the cases for which the discharge does not directly involve the insulators (e.g. V-type string or / string with shielding electrodes). Discussers: B. Hutzler, T. Shindo and T. Suzuki