针对西藏110 kV当—那—安线故障频发现象，分析了线路故障跳闸的原因，得出了高海拔地区空气密度、大气压强的变化对架空输电线路安全可靠运行的影响。在满足线路安全运行及控制线路合理造价的基础上，推导了高海拔地区新建架空输电线路外绝缘及空气间隙计算方法，可有效解决高海拔地区新建架空输电线路外绝缘和塔头空气间隙的设计配置问题。

In allusion to the frequent accidents occurred in the 110 kV Dangxiong-Naqu-Anduo transmission line in Tibet, reasons for line trip were researched. It was analyzed that changes of atmosphere density and atmosphere pressure can affect the safety and stability of over-head power transmission lines’operation. On the basis of maintaining safe operation at a reasonable project cost, the algorithms for the external insulation design of newly-constructed over-head transmission lines, and the air gap of transmission towers in high altitude areas were deduced, which can effectively solve problems in this regard.