Pultrusion made materials for outdoor insulation and their HV tests

Abstract

The aim of the article is to present the results and applied procedures of high-voltage (HV) tests used to evaluate tested insulating material in terms of electrical resistance. The HV voltage tests on the materials were based on the requirements for testing insulators at similar voltage levels. Samples of material in the form of bars were exposed to alternate voltage stress (AC) and lightning impulse stress (LI). The aim of the tests was to select an insulation material with optimal properties. The monitored parameter was the flashover voltage over the surface of the material. At the first stage tested insulation materials were exposed to LI stress. The results obtained by applying the LI voltage over the entire length of the insulating bar show no differences between the materials. Subsequently, the LI up-down test method was used. The results obtained by this method allowed us to make the first selection of materials. In the next step, the AC and LI stress tests of the selected and progressively improved insulation materials continued. The designed procedure of performing high-voltage tests on samples of insulation proved that, based on the obtained results, it is possible to classify individual insulating materials in terms of voltage resistance.