Analysis on Wires Icing and Its Weather Conditions in Guizhou Province
Using observation data of wires icing from meteorological stations and field investigation to power line ice coating from local electricity sections, this study comprehensively analyzes the properties, classifications and distributions of wires icing in Guizhou Province as well as its weather conditions. Emphasis is placed on discussing the mechanisms of wires icing and its weather causes of formation. The results show that (1) there are multiple types of wires icing in Guizhou Region. In addition to glaze, rime, and wet snow, mixed freezing types of freezing rain and fog, freezing rain and wet snow are common. Glaze dominates and mixed freezing prevails in mountainous areas, leading to severe wires icing disasters. (2) The freezing weather of continual low temperature and rainy days are the weather conditions of the formation of wires icing, which includes freezing rain, freezing drizzle, sleet, wet snow and freezing fog. (3) Wires icing in Guizhou is generally controlled by moist physical processes with temperature below or near 0℃ and slow wind speed (<6 m·s-1). In most cases wires icing starts and grows under weathers of freezing rains when the temperature falls below 0℃. Therefore, air temperature below 0℃ and occurrence of freezing rain, freezing drizzle, freezing fog or sleet are important indicators to judge wires icing.