超高压电缆蛇形敷设方式选择

Selection of Snake Laying Methods for EHV Cables

对于大截面电缆,导体温度的变化引起热胀冷缩将产生很大的机械力,常用而有效的解决方法就是对电缆采取蛇形敷设释放其机械力。针对超高压电缆蛇形敷设方式,对电缆热伸缩量、蛇形节距等计算公式进行了推导分析以有助于理解热伸缩原理;并对蛇形弧幅、蛇形弧节距、占有幅、轴向力等参数的设计条件以及注意事项提出建议,对正确使用计算公式尤为重要;比较了水平蛇形与垂直蛇形敷设方式优缺点,有助于合理选择电缆蛇形敷设方式和参数。结合工程案例,对电缆蛇形敷设方式进行了计算分析与长期循环试验试验,进一步验证了敷设方式选择的正确性。

For cables of large sectional area, the thermal expansion and contraction produce very large mechanical forces because of changes of the conductor's temperature, and the effective method to address the mechanical force is to adopt the snake laying pattern to release the force. In this paper, the calculation formulas of the expansion and contraction and the snake pitch are analyzed and derived to help to understand the thermal expansion and contraction principles and suggestions on the design conditions and precautions for parameters such as the snake arc, pitch, the occupied arc width and axial force are made accordingly. The paper compares the advantages and disadvantages of both the horizontal and vertical snake laying patterns to make the reasonable choice of the cable laying pattern. The analysis and long-cycle testing of the snake cable laying pattern in a practical engineering case verify correctness of the choice.