设置SG-RUBT装置110kV输电铁塔的受力分析及设计方法

Force analysis and design method of 110kV transmission tower with SG-RUBT device

输电线路设置SG-RUBT装置后可在纵向不平衡张力超过设定限值时通过悬垂串在装置内自行前后滑动释放不平衡张力.然而,随着悬垂串滑离中心位置,横担及铁塔塔身将受到一定偏心荷载.选取110kV双回1F3-SZ2型输电塔,建立输电塔模型并对结构进行受力分析,对设置SG-RUBT装置后不均冰工况荷载大小和受力位置进行讨论,考察输电塔主材、横担、横隔、斜材的内力和铁塔的侧向位移变化特点及变化率.分析结果表明,设置SG-RUBT装置后输电塔主材受力仅在横担附近内力增大,铁塔横担以下主材内力均减小;横担部位受力状态产生较大变化,横担下平面主材需要进行重点设计,以满足铁塔稳定要求;采用装置后铁塔的塔顶位移和横担位移均有所减小.因此,设置SG-RUBT装置并适当提高横担附近主材规格以及对横担下侧杆件合理分段后,可提高铁塔抵抗不平衡张力的能力.

After the SG-RUBT device is installed on transmission tower, the unbalanced tension can be released by the sliding of the suspension string in the device automatically when the unbalanced tension exceeds the design limit. However, as the suspension string slides to the end of the device, the tower is subjected to eccentric loads. The 110 kV transmission tower is selected and the analysis model is established to study the stress variation in the members. The load and the force position of the unbalanced ice condition are studied, and the forces of main members, the cross arm and the tabula along with the lateral displacement are compared between the tower with and without SG-RUBT. The results show that the force of the main members are increased only in the vicinity of the cross arm after setting the SG-RUBT and the rest member forces decrease. The force characteristics of the cross arm have a great change and the lower side of the cross arm need to be designed carefully. On the other hand, both the top displacement and the cross arm displacement are reduced. Above all, it is possible to improve the capacity of the transmission tower against the unbalanced tension by subdividing the lower side of the cross arm properly and re-designing the size of main members around the cross arm appropriately after setting the SG-RUBT.