Abstract
To maintenance power distribution equipment efficiently and to design electrical rooms of factories, office buildings appropriately, it is essential to clarify the complicated factors causing degradation of insulators, which are important in determining the service life of electric installations. We evaluated the effects of the installation environment, the type of insulators, the rated voltage, and the outer air flowed into the interior from the inlet for power distribution equipments on concentration and composition ratio of ions on polyester insulators, phenol insulators, and epoxy insulators. Concentration and composition ratio of ions on insulators had close relations with the exposure of exhaust gas to insulators, but the relation between concentration, composition ratio of ions and the rated voltage could not be identified. Concentration of ions on polyester insulators was the highest. There was a good correlation between the outer air flowed into the interior from the inlet and the degradation of insulators, and the degradation speed of insulators at the upwind in power distribution equipment was faster.
