高压架空输电线路覆冰情况下风险评估研究

摘要

This paper analyzes the reliability risk evaluation method for the high voltage overhead transmission line under heavy icing condition. The finite element calculation model which considers non-linear material and coupled character of the tower-line system is built. The stress distribution and deformation of the tower-line system are analyzed considering the ice thickness and wind speed parameters. Based on iterative correction method, a new form-finding method is applied to determine the initial state of the sag, and then both the initial strain range and the shape of the grounding line are determined. Furthermore, tower safety margin evaluation method is proposed. On the basis of finite element calculated results of tower-line system under various ice thickness and wind speed condition, regression analysis is adopted to obtain the safety margin curve of the tower. The safety margin curve intuitively describes the relationship between ice thickness, wind speed and the tower failure rate level. The safety margin curve of the tower of a 500 kV icing transmission line is calculated and the vulnerable area of the tower is obtained. Comparative curve of safety margin demonstrates the validity of the improved corrective recommendations.%对覆冰情况下的高压输电线路进行了风险评估研究，建立了有限元计算模型。该模型考虑材料非线性以及塔-线系统耦合特性，分析了不同覆冰厚度和风速情况下塔-线系统的失效情况。采用基于迭代修正的找形方法，准确地对导线弧垂进行了初始化设置，得到了导地线的初始形状和应力。提出杆塔受力安全裕度风险评估方法，采用回归分析方法得到杆塔的安全裕度曲线，该曲线直观地描述了杆塔力学失效度与覆冰厚度及风速的关系。计算得到某实际线路单塔失效安全裕度曲线，获取各基杆塔薄弱点位置，提出了杆塔的具体改进措施。通过安全裕度曲线对比证明所提出改进措施的正确性和有效性。