表面构型对输电导线覆冰碰撞特性的影响分析

Analysis of the Effect of Surface Configuration on the Collision Characteristics of Transmission Conductor Icing

导线结冰严重影响着电网运行安全,局部碰撞系数是表征输电导线覆冰增长速率的关键指标,以往对传统钢芯铝绞线或其简化圆柱模型的覆冰增长特性进行了分析,碳纤维复合芯导线(Aluminum Conductor Composite Core,ACCC)作为一种发展迅速的新型导线,其局部碰撞系数和覆冰增长过程鲜有研究。首先基于商用有限元软件Fluent实现了对覆冰增长数值模拟,并通过与模拟试验结果对比,验证了仿真方法的有效性。随后,利用经过验证的数值模拟方法,对ACCC模型和简化的圆导线模型的覆冰增长特性进行了对比研究,模拟得到了二者表面的液滴碰撞系数分布,讨论了不同的雨滴中值直径和风速变化对碰撞系数的影响,获取了ACCC模型的结冰冰形。结果表明:风速低时ACCC模型的局部碰撞系数显著小于圆模型,覆冰初期,冰形受导线表面构型影响十分显著;当导线表面被覆冰完全包裹后,圆模型冰形比ACCC模型冰形阻力系数整体低15.3%,且在多个风攻角下呈现驰骋不稳定性。研究结果对于获取ACCC覆冰增长特性,了解不同表面构型导线覆冰致灾机理具有重要价值。

Conductor icing seriously affects the safety of power grid operation,the local collision coefficient is a key indicator to characterize the growth rate of transmission conductor ice cover,the traditional steel core aluminum stranded wire or its simplified cylindrical model of the growth of the ice cover characteristics of the previous analysis,the aluminum conductor composite core(ACCC),as a new type of conductor that is developing rapidly,the local collision coefficient and the growth process of the ice cover has rarely been studied.First realized the numerical simulation of ice cover growth based on the commercial finite element software Fluent,and verified the validity of the simulation method by comparing with the simulated test results.Subsequently,using the validated numerical simulation method,a comparative study of the ice cover growth characteristics of the ACCC refined model and the simplified circular conductor model was carried out to simulate the distribution of droplet collision coefficients on the surfaces of the two,and the effects of different median diameters of the raindrops and the change of the wind speed on the collision coefficients were discussed,and the icing ice shapes of the ACCC model were obtained.The results show that:the local collision coefficient of ACCC model is significantly smaller than that of round model when the wind speed is low,at the early stage of ice-covering,the ice shape is very significantly affected by the surface configuration of conductor,when the surface of conductor is completely wrapped by the ice-covering,the resistance coefficient of the round model is 15.3%lower than that of the ice shape of ACCC model as a whole,and it shows galloping instability under each wind attack angles.The results of the study are valuable for obtaining the growth characteristics of ACCC ice cover and understanding the disaster mechanism of ice cover on conductors with different surface configurations.