Characteristics of leakage current, electrical field and surface resistivity of artificially polluted high voltage composite insulators for different composite materials in their structure, equivalent salt deposit density, electrolyte flow-rate and hydrophobicity are discussed, analyzed and presented in this paper. All these parameters are compared with conventional non composite insulators, too. Relativity of leakage current, applied electric field, electrolyte flow-rate and electrolyte conductivity to the environmental conditions are presented by the results of artificial pollution tests. Waveform, frequency spectrum and magnitude-phase diagram of leakage current of polluted insulators with different pollution densities and durations and applied voltages are presented. Surface resistivity of different insulators is compared regarding different kinds and densities of pollution. Electrical field causing flashover for polluted insulators as a function of the insulators' surface hydrophobicity and salt deposit density is also presented. Through the study, investigating the life time of being used insulators is achieved by measuring their leakage current, salt deposit density and surface resistivity and comparing with the test results
