中美两国现行输电线路设计规范风荷载计算参数对比分析

Comparative Analysis of Wind Load Calculation Parameters in Current Transmission Line Design Specifications between China and the United States

摘要:

中国输电线路设计规范与美国存在一定的差异，为较好地适应国外电网工程设计，选取美国ASCE 74—2009《输电线路结构荷载导则》与中国GB 50545—2010《110 kV~750 kV架空输电线路设计规范》，针对两者风荷载计算公式中的风压高度变化系数、体型系数、风荷载调整系数及地形影响因子等参数进行了对比分析。结果表明：ASCE 74—2009中的风压高度变化系数小于GB 50545—2010设计值；GB 50545—2010的导、地线体型系数比ASCE导则值大10%～20%；ASCE 74—2009的阵风响应因子与GB 50545—2010中的塔身风荷载调整系数大致相同；当设计风速超过27 m/s时，两者的线条风荷调整系数差距较小；对特殊地形，ASCE 74—2009考虑了地形影响因子，但在实际工程中的应用范围较小；GB 50545—2010与ASCE 74—2009中对杆塔构件和导、地线覆冰时的风荷载计算存在较大差异，ASCE 74—2009通常不考虑覆冰引起的结构挡风面积增加的影响。

Abstract:

There are certain differences between design specifications of transmission lines in China and the United States. In order to better adapt to the design of foreign power grid engineering, ASCE 74—2009 "Guidelines for Structural Load of Transmission Lines" in the United States and GB 50545—2010 "Design Specification for 110 kV~750 kV Overhead Transmission Lines" in China are selected to compare and analyze the parameters such as wind pressure height variation coefficient, shape coefficient, wind load adjustment coefficient and terrain influence factor in wind load calculation formulas. The results show that the coefficient of wind pressure height variation in ASCE 74—2009 is smaller than that of GB 50545—2010. The shape coefficient of conductor and ground wire in GB 50545—2010 is 10% to 20% higher than ASCE guideline value. The gust response factor of ASCE 74—2009 is roughly the same as the tower body wind load adjustment factor in GB 50545-2010.When the design wind speed exceeds 27 m/s, the difference in line wind load adjustment coefficients between these two is small. For special terrains, ASCE 74—2009 considers terrain influence factors, but its application scope in practical engineering is relatively small. There are significant differences in the calculation of wind loads on tower components and conductors and ground wires when they are covered with ice between GB 50545—2010 and ASCE 74—2009, ASCE 74—2009 typically does not consider the impact of increased structural windbreak area caused by icing.