多种覆冰形状导线风荷载增大系数研究

Study on Wind Load Increase Coefficient of Conductors with Various Ice Coating Shapes

根据导线风阻力的计算原理推导了覆冰导线风荷载增大系数。基于覆冰导线的气动力系数风洞试验结果,分别计算了不同覆冰厚度、不同覆冰种类的圆截面覆冰导线、新月形覆冰导线和D形覆冰导线的风荷载增大系数,给出了便于工程设计和校核使用的覆冰导线风荷载增大系数的取值用表。结果表明,3种覆冰形状导线的风荷载增大系数均受实际覆冰厚度与覆冰种类的影响,其值随覆冰厚度的增大而增大、随覆冰密度的增大而减小。理想圆截面覆冰导线的风荷载增大系数在覆冰密度较小时的部分工况大于规范取值,在覆冰密度较大时均小于规范取值。新月形和D形覆冰导线的风荷载增大系数还与对应风攻角下的阻力系数有关,两者的风荷载增大系数取值在多数风攻角下小于规范取值。

The wind load increase coefficient is derived in accordance with the calculation principle of wind resistance of the ice-coated conductor. Based on the results of aerodynamic coefficient wind tunnel test of ice coated conductor,the wind load increase coefficient of circular section ice-coated conductor,crescent ice-coated conductor and D shape ice-coated conductor with different ice coating thicknesses are calculated respectively and recommended value tables of wind load increase coefficient for the convenience of engineering design and check work are given.The results show that the wind load increase coefficient of three kinds of ice-coated conductors are influenced by actual ice coating thickness and type and their values increase with the increase of ice coating thickness and decrease with the increase of ice coating density.The wind load increase coefficient of ideal circular section ice-coated conductor,in case of partial condition when the ice coating density is small,is higher than the specification value and,in case of larger ice coating density,is less than the specification value. The wind load increase coefficients of both crescent and D shape ice-coated conductors are also related to the resistance coefficient under corresponding wind attack angle and the value of the wind load increase coefficient of them are less than the specification values under most wind attack angles.