Aerodynamic drag of new-design electric power wire in a heavy rainfall and wind

The authors have studied out grooved round transmission wires, developing Model LP-810 wire with lesser drag. Aerodynamic characteristic of grooved round transmission wires were studied in wind-tunnel experiments. But being located outdoors, electric power transmission facilities are subject to the design limit loading in a strong wind, which, in most cases, is based on typhoon-weather conditions. Consequently, the wind-tunnel experimentation needs to attach a factor of rainfall to the simulated wind conditions (usual wind conditions). In this laboratory test, the authors set up a watering grid upwind in the wind-tunnelʹs test section, which simulated a number of rainfall: 0, 2, 4, 8, 10, 16, 25 and 40 mm per 10 min. Those rainfalls were rationalized, based on the domestic weather observation data: 10 min cumulative amounts of rain and 10 min mean wind speeds of time frame. Thus, LP-810 was tested under simulated, rational wind and rainfall conditions, and its design drag coefficients were figured out.