Abstract:

Conducted a number of analyses on the statistical data from the Transmission Departments of China Southern Power Grid in 2006-2010 years, to verify the environmental distinction in which some transmission lines could be tripped by the wildfires,for example, landform, combustible, fire spread, so that we can make a better control and prevention. In this study, taking Guangxi province as an object, the effect on wildfires from climates was demonstrated by the monthly conventional meteorological data in the areas, where average temperature, precipitation, minimum relative humidity and forest fires between 1999 and 2004 would be covered. The results showed that the forest fires in Guangxi Province mainly occurred in winter and spring,which accounted for 37.4% and 37.0%, respectively. Few firesoccurred in summer; The proporion of burned area was the highest,accounting for 46.8%, followed by spring, accounting for 33.7% . More fires were recorded in Baise, Liuzhou and Wuzhou,where the transmission line trips caused by wildfires were 9.2%, 12.5% and 4.7%, respectively, and where the vegetation type mostly occurring in the weeds, pine and fir trees with DBH of 0.02~0.45 m (mostly were over 0.1m) and height of 2.0~23.0 m (mostly were 5.0~10.0 m), that were ranged from 3 years to 21 years old. The power trips places were on sunny slopes with a gradient of 16°~80°, of which in the mild slope of <30° and in the steep slope bewteen 30°~60° occurred 56% and 36%, respectively.The fire styles causing trips were those surface fires and crown fires, with spread speed of over 2.1 m/min, flame height of over 1.5 m, and fire intensity of over 750 W/m2. As the results indicate, it is suggested that the areas prone to fire should be early warned, monitored and managed to prevent power cuts and people security from the wildfires. It can provide scientific and theoretical criteria and practical assessment method for establishing relevant exploitation scheme and efficient fire prevention measures.

Key words: wildfire, transmission line trip, environmental distinction, control efforts