EVALUATION OF SNOW ACCRETION PROPERTIES OF INSULATORS BY FIELD OBSERVATION AND ARTIFICIAL TEST-FOCUSING ON PACKED AND WET SNOW CONDITION-

摘要

Snow accretion properties of insulators were evaluated by field observation and artificial test. In the field observation, we carried out remote observations of snow accretion on insulators over the two sequential winters at Niigata, Japan. During eleven events of snow accretion, gaps between the sheds of insulators were bridged with relatively large amounts of snow. Most accretion events occurred during periods of low wind velocity, with only one case occurring during a period of strong winds. During this remarkable event, the gaps between the sheds of long rod insulator were covered with the packed snow to some extent, but they did not bridge completely between the sheds as a result of insufficient precipitation. During artificial snow accretion tests, a wind tunnel was used to deposit snow particles onto the insulators using snow taken from outside of the facility. Snow accretion properties of the insulators were evaluated by observation of the accreted snow shape and the amount of snow usage untill snow bridged between the sheds. Wind velocity was varied from 5 to 15 m/s In the case of 5 m/s, snow accreted readily on the sheds. In the case of higher wind velocity, snow accreted to the part of rod and caps with packed and wet conditions. At the higher wind velocities, larger amounts of snow was needed for bridging between the insulator sheds.