Study on Probability Distribution Model of Air Density for Transmission Lines Corridor in High-altitude Regions

Data analysis on air temperature, relative humidity and atmospheric pressure from a typical national meteorological station in 4200m high-altitude regions was carried out. Time duration of the meteorological data is more than 30 years. Statistical values of air density in this national meteorological station were calculated. Whether analyzing by year average meteorological data, month average meteorological data or day average meteorological data in the month with the highest wind velocity, the air density in high-altitude meteorological station conforms to the normal distribution. The year average air density is basically equal to the month average value. The day average air density is higher than the year or month average value by 6.1%. When the altitude height is close and the terrain is similar, the statistical air density based on the field observation data near the transmission lines corridor basically meets well with the values based on 30-year data from national meteorological stations. The relative variances between the field measured 10min average air density and the year average air density, the month average air density as well as the day average air density are 2.3%, 2.4% and7.9% respectively.