导线覆冰过程中水滴尺寸参数影响的碰撞率分析

Collision efficiency considering water droplet size parameter during icing of transmission lines

导线覆冰增长预测中,碰撞率是一项不可忽视的重要参数,该参数的合理获取与实时环境参数如风速、水滴直径、温湿度、气压及导线直径等密切相关。水滴中值直径(MVD)常用来近似整个滴谱,但计算表明,对于不同体积百分比的水滴分布,基于MVD的碰撞率与实际滴谱碰撞率相差较大。论文提出了新的体积权重直径(VWD)来近似滴谱,分析三种水滴尺寸参数的碰撞率,基于VWD的碰撞率更接近实际滴谱的碰撞率,相对误差较小。解析了基于VWD的碰撞率精度更高的数学原理,讨论了该方法的适用范围。同时,通过试验的对比分析,计算碰撞率和实测碰撞率相对误差较小,覆冰质量接近,验证了该方法进行覆冰预测的可靠性,进一步将其应用于实际输电线路的覆冰厚度预测。

Collision rate is an important parameter that cannot be ignored in the prediction of icing growth of wires.The reasonable acquisition of this parameter is closely related to real-time environmental parameters such as wind speed,droplet diameter,temperature and humidity,atmospheric pressure and conductor diameter.The median diameter of droplet(MVD)is often used to approximate the whole droplet spectrum,but the calculation shows that the collision rate based on MVD differs greatly from the actual droplet spectrum collision rate for droplet distributions with different volume percentages.In this paper,a new volume weighted diameter(VWD)is proposed to approximate the droplet spectra.The collision rates of three droplet size parameters are analyzed.The collision rates based on VWD are closer to the actual droplet spectra,and the relative errors are smaller.The mathematical principle of higher accuracy of collision rate based on VWD is analyzed,and the application scope of this method is discussed.At the same time,through the comparative analysis of the test,the relative error between the calculated and measured collision rates is small,and the ice quality is close to each other,which verifies the reliability of the method for ice prediction,and further applies it to the ice thickness prediction of actual transmission lines.